Do you want to buy the powersupply kit ? - Page 1
Forum section: electronics / general

author: Blue
author_rank: Regular Contributor
timestamp: January 06, 2012, 05:54:21 pm
content: You will see the results after voting.And you may change your mind after voting.Please elaborate in this post.

author: IanB
author_rank: Super Contributor
timestamp: January 06, 2012, 06:44:20 pm
content: I am waiting to see the end of the story. So far it is still incomplete and there are some design decisions I don't yet understand. I am hoping the conclusion of the story will make things clear.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: January 06, 2012, 07:13:26 pm
content: Perhaps. I have some 8 power supplies sitteng around here, so I definitely dont need it,but if the result is nice enough I might get such kit for EEVblog's sake

author: Nick Gammon
author_rank: Contributor
timestamp: January 06, 2012, 08:07:59 pm
content: I would be interested, first to support Dave's attempts to educate people in the fun of electronics.Second, a precision supply with accurately adjustable voltage and current would be a plus. For me, around the 5V mark would be fine because I am generally testing microcontrollers.Third, the inbuilt current measurement would help overcome the almost impossibility of buying the uCurrent device, of which the last batch arrived, and sold out, between about midnight and 8 am local time, when I was asleep.Finally, if necessary, the circuit could be extended (eg. monitoring of the levels via I2C messages), to give data logging capability.

author: The_Penguin
author_rank: Regular Contributor
timestamp: January 06, 2012, 08:35:36 pm
content: I don't *need* another supply, but I may build it, just for it to look cool on my bench, and to support EEVBlog

author: Anders
author_rank: Contributor
timestamp: January 07, 2012, 09:34:14 am
content: Well, to be useful on my bench it would need 0 to 16.5V (or higher) and 1.5A output so I hope a kit will allow this.If not, there are other ways to support Dave and his well explained and very educational projects and other stuff.No matter what the outcome of this power supply I know I’m learning a lot from it, way to go Dave!

author: desowin
author_rank: Contributor
timestamp: January 07, 2012, 01:59:14 pm
content: Voted yes since I don't have any bench power supply yet (so far I have just used the ones available at university)I guess the integrated current measurement would be quite handy for measuring power consumption of microcontroller based projects (especially since I don't have µCurrent).I would especially like if the "essentially integrated µCurrent" output would be easily accessible by scope probes so the peak current bursts could be observed (by the way: is it right thing to measure current peak bursts this way?).

author: 8086
author_rank: Super Contributor
timestamp: January 07, 2012, 02:25:59 pm
content: Depending on the price, yes. At the moment I only have a college freebie coarse/fine psu with no current limit.

author: G7PSK
author_rank: Super Contributor
timestamp: January 07, 2012, 05:28:55 pm
content: Depending on costs and cost to get it to UK yes as I don't have a proper power supply at present. One that gave 90 volts at 1 amp would be nice to test larger avr's.

author: Unknown
author_rank: Unknown
timestamp: January 07, 2012, 06:20:35 pm
content: Quote from: G7PSK on January 07, 2012, 05:28:55 pmGood luck getting 90 V from a monolithic voltage regulator. 5 V/1 A from a 90 V/1 A linear supply requires an awful lot of cooling. Plus theAVRsI'm familiar with only go up to 5.5 V or so.

author: don.r
author_rank: Frequent Contributor
timestamp: January 07, 2012, 06:41:49 pm
content: Quote from: alm on January 07, 2012, 06:20:35 pmAudio/Video Receiver? I really do despise acronyms sometimes...

author: Greg J
author_rank: Regular Contributor
timestamp: January 07, 2012, 08:16:00 pm
content: I would probably buy one or two, just to support Dave (even tho I support him every month anyway). Providing they'll be more readily available then uCurrent thingie !But I am going to mod the design before I use it.One thing for instance is modularisation. Separate uC block from the rest of the power supply.Because if I want to have two power supplies in one (+ static 5V, 3V3 and 12V outputs - with no current cap) + two regulated one, what do you do ?To make it modular, it needs to be smaller too - so I need to make it at least partially SMD.To make at least one of them triggered by an external signal (a useful feature sometimes) - I need to add an relay or something (mosfet, etc).Perhaps I want to capture and read current output using the uC, I need USB connector. For that, having separate uC board makes a lot of sense, because you can then replace it as you go.Modular designs FTW !(and yes, I'm a software engineer).

author: JuKu
author_rank: Frequent Contributor
timestamp: January 07, 2012, 08:53:55 pm
content: Umm, what kit?(I'm sorry, but even though the subject is interesting, I don't have time right now to sit through six episodes about power supply designs, 3/4h each.)

author: don.r
author_rank: Frequent Contributor
timestamp: January 07, 2012, 08:59:17 pm
content: Quote from: JuKu on January 07, 2012, 08:53:55 pmDave's making the PSU project into a kit.

author: EEVblog
author_rank: Unknown
timestamp: January 07, 2012, 10:42:00 pm
content: Quote from: Greg J on January 07, 2012, 08:16:00 pmI can't possibly make it all things to all people and I'm not even going to try.I had a specific goal in mind for this supply when I started, and that's what it's going to be. Catering for everyone's wildest requirements in a power supply is just not possible.Dave.

author: Greg J
author_rank: Regular Contributor
timestamp: January 08, 2012, 12:18:40 am
content: And by making it an open design you do make it possible for us to at least attempt to tailor it to our needs. Thank you for that !

author: amspire
author_rank: Super Contributor
timestamp: January 08, 2012, 01:21:06 am
content: I was thinking I don't need another power supply right now, but it struck me how well this would work off a 12V SLA battery. The idea has probably been obvious, but it only just registered with me.It should be pretty conservative of power, the LT regulator is low dropout, and the current sense resistors could probably could be lowered at the expense of accuracy. So it may be able to output 0 to 10V with only 11V battery voltage.There is probably a good chance that some kind of 12V battery could be fitted into the case above the PCB. 3AH would probably be plenty, but even 1.2AH would be useable. It could be a pretty handy portable DC power supply, and also as a supply to run of a car cigarette lighter socket.Richard.

author: EEVblog
author_rank: Unknown
timestamp: January 08, 2012, 07:17:39 am
content: Quote from: amspire on January 08, 2012, 01:21:06 amDave.

author: Rerouter
author_rank: Super Contributor
timestamp: January 08, 2012, 07:22:01 am
content: only thing to worry about running off of a lighter socket is the op amps fry at 14V (alternator can float a battery around 15V in some cases)so just make sure you swap them out or protect them

author: benemorius
author_rank: Regular Contributor
timestamp: January 08, 2012, 08:19:15 am
content: Quote from: EEVblog on January 08, 2012, 07:17:39 amI knew it!Now I'mreallylooking forward to the remaining videos!

author: benemorius
author_rank: Regular Contributor
timestamp: January 08, 2012, 08:21:32 am
content: Quote from: Rerouter on January 08, 2012, 07:22:01 amIt's a given that good transient protection and regulation is needed in an automotive environment. Never mind a measly 15v - transients can be upwards of 60v.

author: G7PSK
author_rank: Super Contributor
timestamp: January 08, 2012, 09:18:12 pm
content: Sorry when I talk about AVR's I tend to mean the field regulators for power alternators what usualy happens is they get replaced and the old ones binned but as they can cost several hundreds of pounds I have wondered about trying to fix them or those that are not encapsulated in resin at least.

author: rr100
author_rank: Frequent Contributor
timestamp: January 09, 2012, 12:27:03 pm
content: I would buy one for sure if the price is right. And I don't mean to compete with all the cheap chinese stuff on ebay; but many of us leave on another continent and if it goes up to 200$ with shipping and customs and Dave barely makes it even out of this it's not worth considering.Maybe some cheap(ish) kit with only the board and the parts that might be hard to source locally (especially if they can be ordered in bulk) would be a good idea. If it's fitting in a cheap-to-ship padded envelope even better.

author: Short Circuit
author_rank: Frequent Contributor
timestamp: January 09, 2012, 02:18:28 pm
content: Quote from: benemorius on January 08, 2012, 08:21:32 amAnd then some, ISO7637-2;- pulse 1: -75 to -100V- pulse 2a: +37 to +50V- pulse 3a: -112 to -150V- pulse 3b: +75 to +100V- pulse 5a: +65 to +87V (40-400msec pulse! the infamous loaddump)that's only the values for 12V systems!

author: PStevenson
author_rank: Regular Contributor
timestamp: January 09, 2012, 07:23:40 pm
content: I really want to get one of these beauts, I also want to lay one out for an iTead board to see how shit I am at PCB design compared to Dave.

author: EEVblog
author_rank: Unknown
timestamp: January 09, 2012, 10:20:29 pm
content: Quote from: rr100 on January 09, 2012, 12:27:03 pmIt should be well under this. Although I have no idea how customs works in every country.No way anyone can compete with the 30V/3A supplies from China.Dave.

author: technobabble
author_rank: Newbie
timestamp: January 09, 2012, 10:36:06 pm
content: I am REALLY looking forward to having a decent lab supply. I'm using an old ATX supply in a cigar box right now, it's horrible. +5.41v while the -5.00 is spot on. The +12 is +11.37, etc...I do have a question: Is the kit going to come as a PCB plus parts, or do we buy the parts ourselves on mouser, digikey, etc? I'm sure if Dave bought the components 1000+ at a time it'd be cheaper, but some might want to just get the PCB itself with no parts.

author: EEVblog
author_rank: Unknown
timestamp: January 09, 2012, 10:52:09 pm
content: Quote from: technobabble on January 09, 2012, 10:36:06 pmThe idea is it's a complete kit.The problem with just the PCB itself is that it's not really worth my while to post it overseas, it's just too much hassle for a low priced product.Dave.

author: mobbarley
author_rank: Regular Contributor
timestamp: January 09, 2012, 11:42:51 pm
content: I'd only buy a kit if it supports Dave - otherwise I'd whip up my own PCB to my specs.

author: Blue
author_rank: Regular Contributor
timestamp: January 10, 2012, 02:25:01 am
content: I'll buy a whole kit.Customs in Europe are a pain in the ass: They charge over the complete package: Product (OEM is cheaper) plus shipment. Then you have to pay vat over the total. Argh.So the best way is to ship it as a gift!I'll support Dave (gift) and Dave sends a gift.Have fun

author: Unknown
author_rank: Unknown
timestamp: January 10, 2012, 05:49:20 am
content: Fraud is illegal in most countries, even in the former prison island Oz. Padded envelops tend to be much less likely to be picked up by customs than boxes, although depending on the case size this may not fit.

author: EEVblog
author_rank: Unknown
timestamp: January 10, 2012, 05:53:36 am
content: Quote from: Blue on January 10, 2012, 02:25:01 amI won't ship things marked as a "gift", sorry.Dave.

author: BravoV
author_rank: Super Contributor
timestamp: January 10, 2012, 05:58:26 am
content: Quote from: EEVblog on January 10, 2012, 05:53:36 amI think you should put these words somewhere at your shop as well, and save some of your energy in replying this kind of requests in the future.

author: don.r
author_rank: Frequent Contributor
timestamp: January 10, 2012, 03:03:48 pm
content: Quote from: EEVblog on January 10, 2012, 05:53:36 amSounds like another T-shirt!

author: Blue
author_rank: Regular Contributor
timestamp: January 10, 2012, 03:43:53 pm
content: I just checked it with the customs website:Below €150 no customs import tax but still vat over the total incuding shipment.And below €22 no tax or vat.

author: thilo
author_rank: Regular Contributor
timestamp: January 10, 2012, 04:39:29 pm
content: You'd pay vat for things you buy in your country as well. So is only fair to pay for imported things too

author: RJSC
author_rank: Regular Contributor
timestamp: January 10, 2012, 05:12:13 pm
content: Quote from: thilo on January 10, 2012, 04:39:29 pmExcept you pay VAT 2 times! On the origin country (VAT over product and shipping) and on your own country again!

author: IanB
author_rank: Super Contributor
timestamp: January 10, 2012, 05:22:31 pm
content: Quote from: RJSC on January 10, 2012, 05:12:13 pmTechnically you don't have to pay VAT on things that are being exported outside the EU. For instance if I buy things from Amazon UK for delivery to the USA they subtract the VAT at checkout. It's always worth checking with the seller to see if similar rules apply in each case.

author: thilo
author_rank: Regular Contributor
timestamp: January 10, 2012, 06:14:36 pm
content: Quote from: RJSC on January 10, 2012, 05:12:13 pmAre you sure? For example if you buy in the us you pay different taxes depending on the state your living in and hence websites list prices without including taxes. Now when I buy in the us as a European I never name a us state and just pay the price listed on the website+shipping. Have you made a different experience?

author: 8086
author_rank: Super Contributor
timestamp: January 10, 2012, 06:28:24 pm
content: When you buy components for something like this, you pay VAT on them. Then you put it together and mark it up a bit, ship it, and people have to pay whatever VAT their country says they have to. So you pay twice. Unless there's some place along the line that you can get some of the VAT back, in which case I would love to hear about it.

author: IanB
author_rank: Super Contributor
timestamp: January 10, 2012, 06:35:43 pm
content: Quote from: 8086 on January 10, 2012, 06:28:24 pmIf you are a business you can register for VAT (must if you are above a size threshold), and as a VAT registered business you can reclaim or deduct VAT on your business purchases (parts, services). So you buy stuff VAT free. But the other side of the coin is that you must then charge and collect VAT on your sales (products, services rendered).

author: ejeffrey
author_rank: Super Contributor
timestamp: January 10, 2012, 06:42:24 pm
content: Quote from: 8086 on January 10, 2012, 06:28:24 pmThat is not true at all, at least within the EU. You would only pay VAT on the 'value added' at each step, hence the name. Businesses don't pay VAT on goods they buy that go into finished products which the sell. The same is true within the US for sales tax. Likewise, when exporting, you can get the VAT refunded or don't have to pay sales tax. Actually dealing with all the bureaucratic nonsense when dealing internationally may be difficult or expensive for a small one man shop like dave's -- I don't know, I haven't tried, but it should be possible.

author: Spikee
author_rank: Frequent Contributor
timestamp: January 10, 2012, 08:11:29 pm
content: If the price is right i will buy one.Not looking for a bargain but as a student you have to watch your wallet.

author: 8086
author_rank: Super Contributor
timestamp: January 10, 2012, 08:13:21 pm
content: Quote from: ejeffrey on January 10, 2012, 06:42:24 pmTo do this you need to register a business i believe? Or can you do it as a sole trader?

author: Spikee
author_rank: Frequent Contributor
timestamp: January 10, 2012, 08:24:29 pm
content: In The Netherlands you can start a one person company by just filling in an form and it costs like 50 euro /year.A company HAS to pay VAT but they get it BACK at the end of the year.So its not true that you dont have to pay... you have to pay but get the VAT back later in the year.

author: Blue
author_rank: Regular Contributor
timestamp: January 10, 2012, 08:27:11 pm
content: Quote from: IanB on January 10, 2012, 05:22:31 pmSure, for you it is ok. You only pay vat in your own country. And that can be zero. In Europe the Vat =18-21 %. Customs dues are depending on the product. It can be as high as the sky. Take for example a €200 suit from Hong Kong. It will cost you more that €310 to get it! It's legalized theft (naked short selling is even worse).So I you live in the USA, you have it much cheaper than in the rest of the civilized (?) world.

author: Spikee
author_rank: Frequent Contributor
timestamp: January 10, 2012, 08:38:55 pm
content: 200 euro * 1.19 = 238 euro incl. VAT+ some extra shipping tax above 25 euro is 16,XX euro= 238+16=254 euro (In The Netherlands)If you try cheating and the find out (declaring lower value or ...) you get a fine of 50%so it is 254 euro + (254*0.5)= 381 euro and Ur screwedMy expirience in Europe is as long it is not bigger thand an bubble wrap envelope they wont check it and you dont have to pay anything extra like VAT.If you order an oscilloscope in a big box they will check and you get a fine if the proper value is not declared.

author: firewalker
author_rank: Super Contributor
timestamp: January 10, 2012, 08:46:41 pm
content: How do they calculate value on used items?Alexander.

author: ximox
author_rank: Contributor
timestamp: January 10, 2012, 09:17:45 pm
content: I'll most likely be building it, great to be able to follow along from design to construction. Having the kit is a plus since I'll have to order all the parts anyways.I'm perfectly happy with what Dave comes up with, no design change requests :-)

author: G7PSK
author_rank: Super Contributor
timestamp: January 10, 2012, 09:19:08 pm
content: VAT should only be charged once if the product is going to another eu country the vat should not be charged in the originating country but paid in destination unless there are arrangements in place by the member states such as the UK Germany France and some others where the vat is charged at source and not paid at destination If you are a business you declare it each month as vat paid from another eu member state in order to reclaim it then charge vat at the relevant rate when you resell. But what ever you do do not use UPS or fedex as they not only charge you vat on the import whether it is due or not they also levy a charge for doing so with a minimum charge of £11 for UPS and £10 for fedex get it sent regular mail as that way it will often miss charges even if they are due, over £15 in the UK.

author: Blue
author_rank: Regular Contributor
timestamp: January 10, 2012, 09:50:56 pm
content: Spikee,have a look here:http://www.douane.nl/particulier/internetaankopen/internetaankopen-03.html#P140_8194Not included is the extra you have to pay someone (commercial company) that is doing all the maths and sending you the invoice. After you paid, they will release the package. This hassle will cost you an additional two weeks for delivery.From the above mentioned website: Uiteindelijk kost dat maatpak u € 313,21 plus de eventuele inklarings- en afhandelingskosten van het post- of koeriersbedrijf.

author: rr100
author_rank: Frequent Contributor
timestamp: January 11, 2012, 03:36:06 pm
content: Quote from: Blue on January 10, 2012, 08:27:11 pmIt is in fact up to (and including)27%(and I'm talking EU only, don't know much about VAT in non-EU european countries).If you hit the customs (as in above the threshold around 100 euro or whatever it is) as mentioned the charges can be really painfull. And I think VAT/customs are applied to the whole value (including postage). I don't know if you pay VAT on the customs charges or vice-versa (I wouldn't be surprised).The postage itself is usually in the tens of dollars for anything other than padded envelopes, especially if you want any tracking or insurance (minimal one, 100-200$). And again as mentioned if you use the DHL and the like they might charge you again some tenners to do the customs for you.Add the 1-3% (or sometimes more) for the transaction itself (either straight credit card charges or paypal "biased" exchange rate) and it's not unusual for the 100$ item to leave you without 150 EUR. That is while staying under the threshold where real "customs" charges would be applied. Not funny.

author: Bloch
author_rank: Unknown
timestamp: January 11, 2012, 06:40:10 pm
content: For Denmark (EU) Text fromhttp://www.toldpriser.dk/toldreglerWhen you buy a product in a country outside the EU, which has a value above 80 kr, you must pay VAT, duty and customs of the goods.The rates at which a shipment must clear customs are as follows:Less than 80 kr: You need not pay customs duties, VAT or customs clearance fee80 to 1,150 kr: You must pay VAT and customs feeOver 1,150 kr: You must pay VAT, customs and clearance feesLet's say you buy some clothes in the U.S. at a price of 1,500 kr,You pay 50 kroner to get the product sent home to Denmark and the duty forexample. jeans and jeans is 12%.Calculation therefore looks like this:Duty is 12% of product value and postage ie. (1,500 kr + 50 kr) * 0.12 = 186krThe VAT is 25% of product value + postage + customs, ie. (1500 + 50 + 186) * 0.25 = 434 krAdd to that clearance fee of DKK 160You will then be charged 780 kr from Tax and Post Denmark to get it to Denmark.When the clothes are at home at your doorstep, you have therefore paid:Price of goods:1500krShipping: 50 krCustoms: 186 krVAT: 434 krFor customs: 160 krTotal:2325 kr

author: Stephen Hill
author_rank: Regular Contributor
timestamp: January 11, 2012, 09:48:58 pm
content: ... back to the original topic.I unfortunately won't be buying the kit because I'm designing my own microcontroller controlled power supply and incorporating some of the idea and techniques that Dave has presented in his design.My design will be using an LM317 instead of the LT3080 because no one seems to sell them in the UK. I've also kept the current limiting opamp instead of the custom current IC.I'm learning so much while following Dave's videos, so even though I won't be buying the kit, I'll be making sure a donation is sent his way.CheersStephenPS: @Dave: After reading a PDF on the web... What is the burden voltage of your Fluke 87? No looking it up!

author: EEVblog
author_rank: Unknown
timestamp: January 11, 2012, 10:07:44 pm
content: Quote from: Stephen Hill on January 11, 2012, 09:48:58 pmConsidering that would be likely written by me :->, I should be able to get this right from memory - 1.8mV/mA?Dave.

author: Stephen Hill
author_rank: Regular Contributor
timestamp: January 11, 2012, 10:29:15 pm
content: Quote from: EEVblog on January 11, 2012, 10:07:44 pmCorrectNow don't ask what mine is. I have no idea!CheersSte

author: Tooms
author_rank: Unknown
timestamp: January 11, 2012, 10:39:57 pm
content: Quote from: Stephen Hill on January 11, 2012, 09:48:58 pmEbay has them

author: Stephen Hill
author_rank: Regular Contributor
timestamp: January 11, 2012, 10:50:41 pm
content: Quote from: Tooms on January 11, 2012, 10:39:57 pmTrue. But I'm not willing to part £7-14 for a voltage regulator. Perhaps we could organise a group buy. Ordering 25 from UK Farnell would cost £4.37 each plus a little for postage. I would still consider this pricey but much better than ebay.CheersStephen

author: IanB
author_rank: Super Contributor
timestamp: January 11, 2012, 10:56:08 pm
content: Quote from: Stephen Hill on January 11, 2012, 09:48:58 pmFarnell appears to have them in the TO-220-5 package at £4.17 each. Is there a hidden catch I am missing?

author: Stephen Hill
author_rank: Regular Contributor
timestamp: January 11, 2012, 11:00:08 pm
content: Quote from: IanB on January 11, 2012, 10:56:08 pm"US Stock items that have a service charge indicated are coming from our Newark warehouse. The service charge will be £15.95 per order, in lieu of a freight charge for Newark items."So this is why I would suggest a group buy. Order we could put pressure to Farnell to stock them locally in the UK.

author: IanB
author_rank: Super Contributor
timestamp: January 11, 2012, 11:16:26 pm
content: Quote from: Stephen Hill on January 11, 2012, 11:00:08 pmAh, that's a bit of a gotcha. But it looks like the SOT-223 package is in stock locally and it's cheaper too. Wouldn't that be an acceptable substitution?

author: im_a_human
author_rank: Regular Contributor
timestamp: January 11, 2012, 11:58:59 pm
content: I would like another powersupply especialy for precision work.

author: Stephen Hill
author_rank: Regular Contributor
timestamp: January 12, 2012, 12:02:03 am
content: Quote from: IanB on January 11, 2012, 11:16:26 pmSuch a small package would very hard, if not impossible to keep cool. See the datasheet for an example.

author: IanB
author_rank: Super Contributor
timestamp: January 12, 2012, 12:30:56 am
content: Quote from: Stephen Hill on January 12, 2012, 12:02:03 amHmm. The datasheet gives a thermal resistance of 3 K/W between junction and case for the TO-220 package, but it does not give an equivalent number between junction and tab for the SOT-223 package. That makes like-for-like comparisons rather difficult. I had thought perhaps to solder the SOT-223 package to a copper heat sink by its tab and use flying leads to the pins. In other words to to turn the SMT part into a make-shift through hole part. For home build construction you don't always have to mount devices in the manner intended for automated production. Would be hard of course with aluminium heat sinks.I'm not sure how feasible it might be...

author: amspire
author_rank: Super Contributor
timestamp: January 12, 2012, 02:12:12 am
content: Quote from: IanB on January 12, 2012, 12:30:56 amThe datasheet has all the thermal specs for the different packages on the second page of the data sheet. The SOT package is 15 DegC/W. The two surface mount packages with 3 DegC/W are the 8 lead plastic DFN package and the 5 lead DD-PAK package. I would think the DD-PAK has the bigger heatsink tab area, so it will probably make the best thermal connection to the heatsink.Richard.

author: IanB
author_rank: Super Contributor
timestamp: January 12, 2012, 04:46:29 am
content: Quote from: amspire on January 12, 2012, 02:12:12 amWell thank you, I didn't spot that.Unfortunately, the DD-PAK is also US stock, so it still commands a nasty surcharge. The DFN package is stocked in the UK, but that thing would be a pain to solder to a big heat sink. As an ex-UK resident, I sometimes think it would be great to have one foot on both sides of the Atlantic and live in both places at once. Sadly there aren't too many jobs that permit that, and it would make filing tax returns horribly complicated.

author: thilo
author_rank: Regular Contributor
timestamp: January 12, 2012, 02:05:44 pm
content: Hey Dave, do you have a ball-park figure for the kit's price yet?And would you consider to provide the kit in a surplus version? I'd like an extra unit of the LT3080 and the SMD components, because I'm sure I'll want to use the 3080 in a future project and I haven't a lot of experience in SMD soldering. I suppose others want spare units of other parts. And I really don't want to burden you with packaging each kit individually. So maybe we could compromise on a surplus unit where all the ICs are included twice (or thrice)?Thilo.

author: plunger
author_rank: Contributor
timestamp: January 12, 2012, 05:41:23 pm
content: What kind of time frame might this happen? I'm in need of my first powersupply.

author: Chet T16
author_rank: Frequent Contributor
timestamp: January 12, 2012, 06:35:36 pm
content: I think as a first power supply something in the generic 0-30v 0-5A range would be better suited. Daves supply is more niche with its lower voltage/current output but far greater precision. Both supplies definitely have their place and i'll be looking to get one of Daves

author: IanB
author_rank: Super Contributor
timestamp: January 12, 2012, 06:54:02 pm
content: Quote from: Chet T16 on January 12, 2012, 06:35:36 pmBut why? What is the basic electronics experimenter going to do with such a beast?For every electronics need I have encountered, 0-12 V and 0-1 A has been more than sufficient.If I have needed more power than that it has been for non-electronics applications like driving lamps or motors. And for that a linear supply is scarcely necessary. A cheaper switch mode supply does just fine.

author: benemorius
author_rank: Regular Contributor
timestamp: January 12, 2012, 07:57:02 pm
content: Quote from: IanB on January 12, 2012, 06:54:02 pmThe thing about a first power supply is that a beginner may not know what the requirements are going to be in the near future. I needed about 15 volts from the first power supply I ever bought. That was for automotive use, which is probably not uncommon at all. If I bought my first one now it would need to do 20+ for a PLC I'm working with. Those are the only two >10V needs I've had that I can think of off the top of my head so I'll certainly agree that 95% of the time or more you won't need that much voltage, but there's still that 5% or less to worry about and this is one case where "almost enough" is no good at all. A typical beginner isn't going to want to have to get two power supplies, so it really seems like a valid goal to try to make the first one as versatile as is reasonably possible.

author: Unknown
author_rank: Unknown
timestamp: January 12, 2012, 08:14:35 pm
content: Quote from: benemorius on January 12, 2012, 07:57:02 pmIt's quite common to need multiple power supplies, so I'm not sure if I agree with your assertion. You may need multiple power supply to provide 12/24V for motors and 5V for logic for example, or 5V and 3.3V logic, or to provide symmetrical power supplies for op-amps. Might as well get two and put them in series/parallel for higher voltage/current.

author: Chet T16
author_rank: Frequent Contributor
timestamp: January 12, 2012, 08:28:18 pm
content: Quote from: IanB on January 12, 2012, 06:54:02 pmI wasn't suggesting 30V and 5A were needed but most of the bench power supplies out there on ebay etc fall in that category.Obviously different people will have different needs but i wouldn't recommend a supply with less than 12V for a first supply which is what Daves will be

author: benemorius
author_rank: Regular Contributor
timestamp: January 12, 2012, 08:33:37 pm
content: Quote from: alm on January 12, 2012, 08:14:35 pmYes, absolutely. No argument there at all. Even two is not enough, eventually. I only meant to suggest that someone who is just getting their feet wet might find one multipurpose supply more affordable than two supplies with narrower ranges.

author: EEVblog
author_rank: Unknown
timestamp: January 12, 2012, 08:46:03 pm
content: Quote from: Chet T16 on January 12, 2012, 08:28:18 pmIt's not designed as a first supply.There are countless 30V/3A supplies on ebay for less than what this kit will cost.This is different, it is not trying to compete, I designed it for a specific reason you have not really seen yet.Dave.

author: plunger
author_rank: Contributor
timestamp: January 12, 2012, 09:34:47 pm
content: Alrighty, for my first power supply I'll get something in the 0-30v 0-5A range. But I'm not buying any cheap ebay stuff

author: McMonster
author_rank: Frequent Contributor
timestamp: January 13, 2012, 12:22:29 pm
content: You willl quickly find out that a good brand PSU can cost well over six times more than those cheap ones.I don't think it's really wrong to get a cheap one for start. Just make sure it has current limiting, not shutdown on excess current.

author: rr100
author_rank: Frequent Contributor
timestamp: January 13, 2012, 08:16:10 pm
content: Quote from: EEVblog on January 12, 2012, 08:46:03 pmHah, sorry but I might've just guessed what's that reason. So, I'm trying to reverse engineer some high capacity Li* batteries (with their own "black box" BMS); I'm using in the process two multimeters, two PSes, two rheostats and a bunch of car bulbs for load (who had the bright idea to put "intelligence" in a battery?!). Anyway I've figured out the algorithm that would eventually work. And I heard a "PIIING". Fortunately only in my head. There are two reasons for which a programmable precision PS would be nice to have:1. except for just dropping the voltage with the load a PS might need to be smarter. You might want to control how the voltage is dropped with the load or even more you might want to control how the PS behaves IN TIME. Example of particular algorithm (which in fact I needed today and I simulate by hand): when the load goes to X Ampere drop the voltage then raise it slowly until you reach a predifined value. We have smart loads, time for smart PSes2. now while I wait for the thing to charge it would be nice to have the power integrated over time and count the energy that was put into the system. This is probably what Dave wants, especially with precision low current measurements and the previous blogs about charging stuff and portable devices, etc. Is this it? Is it? I promise I won't tell

author: all_repair
author_rank: Frequent Contributor
timestamp: January 16, 2012, 04:27:30 am
content: Rough use or charging need, I think Dave kits shall not be able to compete with the Chinese made supplies. I had many of those, as well several HP PS.If Dave power supply can be use as a voltage and current standard to check my multimeters, and as a bonus use for the calibration sources for the 4-20mA instruments as well as some voltage calibration, I would definitely get at least one.But as a kits, I wonder how to adjust for the accuracy.

author: EEVblog
author_rank: Unknown
timestamp: January 16, 2012, 05:25:19 am
content: Quote from: rr100 on January 13, 2012, 08:16:10 pmNope, try again.It's not as complex as you think.In fact, the main driver is so simple, some might even say it's a pointless or silly feature.Dave.

author: Armin_Balija
author_rank: Regular Contributor
timestamp: January 16, 2012, 06:27:18 am
content: Didn't care about all the complaints people were going on about. I ordered all the parts in dave's video and plan to build it up myself. First starting with the original PSU and then going to see if the uSupply is too complicated for me.Thanks Dave!

author: shebu18
author_rank: Frequent Contributor
timestamp: January 16, 2012, 07:15:07 am
content: kind of silly question, when do i use de uCurrent, or why would i use it? You have there 3 conections, V+, V- and sense. Where does sense go? If you answered any of my questions in a blog video then tell mi which and i watch it again.I also ordered all the components and now i will start to build it when they arrive.Thanks.

author: EEVblog
author_rank: Unknown
timestamp: January 16, 2012, 08:12:57 am
content: Quote from: shebu18 on January 16, 2012, 07:15:07 amThere is a whole PDF article on it:http://www.eevblog.com/projects/ucurrent/Dave.

author: vk6hdx
author_rank: Regular Contributor
timestamp: January 16, 2012, 08:38:12 am
content: Quote from: EEVblog on January 16, 2012, 08:12:57 amThe Links on that page all go tohttp://alternatezone.comand seem to be broken at the moment.. is that site down?

author: Chet T16
author_rank: Frequent Contributor
timestamp: January 16, 2012, 08:39:03 am
content: Quote from: EEVblog on January 16, 2012, 05:25:19 amBoobs? Fingers crossed!

author: IanB
author_rank: Super Contributor
timestamp: January 16, 2012, 08:59:40 am
content: Quote from: vk6hdx on January 16, 2012, 08:38:12 amIt was working for me earlier today, but it does seem to be dead right now. I would try again later, perhaps it is just temporarily offline.

author: EEVblog
author_rank: Unknown
timestamp: January 16, 2012, 10:25:20 am
content: Quote from: IanB on January 16, 2012, 08:59:40 amI now recall my provider sending an email about site outage for maintenance, so that must be it.Dave.

author: Blue
author_rank: Regular Contributor
timestamp: February 01, 2012, 04:31:32 pm
content: The poll is still open for a few days.

author: Unknown
author_rank: Unknown
timestamp: February 07, 2012, 05:45:13 pm
content: I totally want one maybe even a second one to mod and keep the first one original. I am in the works of designing my own power supply that is digitally controlled via Arduino but it will be driven differently and have separate specs. Once I saw this build I figured I would get my hands dirty in my spare time in between class work and do one of my own.

author: kiyotewolf
author_rank: Contributor
timestamp: February 08, 2012, 05:13:16 am
content: For people worried about the cost of customs, why not sell the thing as all the custom circuit boards by themselves, some of the hard to find components included in the package, then order parts directly from Digikey or whoever, using a parts list?Break it up into a smaller money figure, by shipping the custom boards, whatever stuff should be sent along that's important, or proprietary, then let the user get the rest of the parts, direct from a supplier?<.< I don't know if that would be better or worse than just the entire kit, all at once.~Paul

author: electrode
author_rank: Regular Contributor
timestamp: February 08, 2012, 05:17:11 am
content: Depends how much stuffing around Dave is willing to do. He could take on the Adafruit strategy, which is generally 3 options:- Full kit- PCB only- Pre-programmed microcontroller15 different options, or a checkbox for every single part for Dave to manually count out and package is not gonna happen...

author: kiyotewolf
author_rank: Contributor
timestamp: February 08, 2012, 05:23:57 am
content: Having a choose your own adventure option is just idiotic, .. make it modest, option one being the PCB's and a few goodies, or the full on Delorean.~Paul

author: EEVblog
author_rank: Unknown
timestamp: February 08, 2012, 05:58:42 am
content: Quote from: electrode on February 08, 2012, 05:17:11 amYes, the less options in my shop to order, the less hassle it is.The only reason Adafruit and similar online shops survive and do what they do is because they have a full time staff of dozens or more and almost fully automated ordering, labeling, and invoicing systems built up over many years.I have the problem of not wanting to be a retail kit business/store, but I also enjoy providing the kits and bits for projects directly myself. So there ends up being this rather annoyingly large intermediate region of success between selling kits/products in the dozens/hundreds, and selling in the thousands, and the "surge" of orders when I announce something.For instance, assembling, testing, packing, and shipping my batches of 50 uCurrents takes several full days of work.The next batch of 200 will take proportionally longer again, probably the best part of a weeks full time work to shift those units. A lot of work, but just manageable without impacting the blog much.Bigger numbers than that, or multiple items in a bigger online store and I'm in trouble.And then there is the customs hassle, where it really isn't worth my while to ship a blank PCB worth $10 or $20 internationally because of the paperwork involved. I can't just pop it in an express satchel and send it. And likewise for multiple items in a shopping cart. It is much easier and more streamlined if everyone orders just the same thing (e.g. I print out labels in batches, wrap and pack things in batches etc). If everyone wants something different in their order then I have to process and pack orders one-by-one to ensure it's not goofed up.I ditched the uCurrent kit because most people didn't want it, and it was a hassle to kit up the SMD parts. But I like the idea for the PSU.It's likely I'll pay someone to kit up these PSU parts for me, as I can't see that being a good use of my time.Of course you could argue that none of this a good use of my time and I should just offload the whole she-bang to Adafruit or Seedstudio and take a small commission. But then the personal joy of it is gone, and someone else gets the majority of the profit.Likewise if I start hiring someone say part-time.I guess it's just suck it and see!Dave.

author: IanB
author_rank: Super Contributor
timestamp: February 08, 2012, 07:21:25 am
content: Quote from: EEVblog on February 08, 2012, 05:58:42 amI don't know if it's different in Australia, but isn't it only necessary to fill out the standard customs declaration form and attach it to the outside of the package? For one off shipments you can fill this out by hand at the post office, but for multiple shipments presumably you can print out the forms at home from a template? (The disadvantage is that printed forms may get more attention from the customs inspectors on arrival than hand-written forms, but hey, what are you gonna do?)

author: EEVblog
author_rank: Unknown
timestamp: February 08, 2012, 07:31:44 am
content: Quote from: IanB on February 08, 2012, 07:21:25 amYes it's a form I fill out. I have a name/address stamp that helps a lot. But it's also standing in line at the post office and then standing there as they scan and enter each one into the system, weight it, record my ID (yes, another stupid thing no doubt driven by Uncle Sam), print the label and put on various stickers, for each package.Some employees are more efficient at it than othersI'm trying to get a way to streamline this, but they are giving me the run-around. So it may get better...Still not as easy as sticking something in a pre-paid satchel and popping it in the box as I do for local stuff.Dave.

author: markus_b
author_rank: Regular Contributor
timestamp: February 08, 2012, 07:57:28 am
content: Seeedstudio provide a service they call 'Propagate' (Propagate description) where they distribute a device (or kit ?) according to your design. They handle everything, including payment and shipment.Looks very interesting to distribute a design to a small to intermediate population.

author: Unknown
author_rank: Unknown
timestamp: February 08, 2012, 08:00:34 am
content: Quote from: EEVblog on February 08, 2012, 07:31:44 amUse a decent international Courier and they do it all and pick up from your doorstep. Cheaper too, just avoid the cowboys.My suggestion (for what it's worth) is to price a few, you may be surprised.For national deliveries air couriers are definitely cheaper and quicker than Auspost.QuoteNot having to go to a post office, isn't easier?

author: IanJ
author_rank: Unknown
timestamp: February 08, 2012, 08:06:34 am
content: Hi all,I probably wouldn't buy the kit, but I'm seriously thinking about the design as a basis for a home built PSU. I'm quite looking forward to extending the design to say 3-rail variable. It's been a long time since I built a PSU and it'd be a great wee project.Ian.

author: sonicj
author_rank: Frequent Contributor
timestamp: February 08, 2012, 08:19:51 am
content: Back when I used to ship a lot, I made a template for CN22 customs forms. Copy, paste, print.-sj

author: EEVblog
author_rank: Unknown
timestamp: February 08, 2012, 09:43:49 am
content: Quote from: Uncle Vernon on February 08, 2012, 08:00:34 amIf an international courier can beat Australia posts prices then I'd love to see it.$12 or so for delivery of the uCurrent to the US.Yes, a pre-paid international courier satchel would be ideal. Aust-post do offer such things via courier service but the price is ridiculously expensive.QuoteI have to go to the post office anyway for my PO box, and it's only a short walk from the lab or a stop on the way to/from.Couriers actually have the annoyance of having to be there all day to hand over the stuff.Dave.

author: Rutger
author_rank: Regular Contributor
timestamp: February 08, 2012, 03:33:44 pm
content: I use Endicia/Dazzle software for all my US Postal service shipments. The software allows me to propagate all the fields via and XML code (pasted to the clipboard) and included the custom information as well. I then print out the label on zebra printer, stick it on the box and I can just drop it off at the post office. I don't have to wait inline. I wonder if there is something similar in Australia, I know there are other companies here in the US that do the same thing, but Endicia was the easiest to integrate with my software.Also I order all my US Postal supplies via the web at no cost and it get delivered to me for free. Endicia also gives a discount rate on the shipping.I thought this might help you Dave if you can get something similar.RutgerPS: I would order a kit, if the kit was more modular. I would have split the design into 2 boards, 1 being a Arduino Shield with the DAC/ADC/LCD/I2C and Encoders interface with the Opamps for the ADC and the other board just being the power supply.

author: IanB
author_rank: Super Contributor
timestamp: February 08, 2012, 03:38:18 pm
content: Quote from: Rutger on February 08, 2012, 03:33:44 pmMy local post office here in the US has a rule that you can't drop off packages larger than a certain size without handing them over in person. Some rule to do with "security"...

author: Rutger
author_rank: Regular Contributor
timestamp: February 08, 2012, 03:47:38 pm
content: My post office has never stopped me dropping of bigger packages, maybe they see the commercial endicia label and they accept it or maybe they are just more relaxed about the rules. What size packages are you talking about?

author: IanB
author_rank: Super Contributor
timestamp: February 08, 2012, 05:26:51 pm
content: I don't remember what size packages, I'll have to check the notice next time I'm there. As I recall it is roughly things too large to fit in a standard mail slot, i.e. boxes rather than envelopes. There's a notice that says if you drop off large packages unattended they will not be delivered--you have to hand them over the counter and can't just put them in the drop box. Come to think of it, the local mailbox in my street has the same notice.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 06:16:55 am
content: Ok, so I've been thinking about the viability of a kit, and discussing with my potential assembler/kitter.It's likely going to be same cost (or even cheaper) to simply have an SMD version of the board assembled, rather than actually supply a through-hole kit.Not terribly surprising, but none the less opens up the discussion about whether to supply a through-hole part kit as intended, or re-jig it and supply a fully assembled SMD PCB, with a small amount of case wiring being the "kit" part.What would people prefer?Dave.

author: electrode
author_rank: Regular Contributor
timestamp: February 13, 2012, 06:26:15 am
content: It's hard to say, but it certainly raises a few questions:1. SMD == smaller PCB -> more room in the case for user mods and such?2. Will you leave the micro controller as DIP so it can be removed/replaced? (Just thinking of your reasoning of a newbie breaking SPI, so separating hardware and software SPI, which reminded me of another newbie mistake, which is to screwup fuses and "brick" the uC, unless you have a parallel programmer...)If the SMD version preserves the original idea of keeping it user-moddable, with intelligent attachment points for headers, etc, then I'd give it the big thumbs up!

author: Rutger
author_rank: Regular Contributor
timestamp: February 13, 2012, 06:58:12 am
content: Go for SMD, but I have always thought you should split the board into 2 parts, one being the pure power supply with the micro amp, change the opamps to accept a higher voltage to allow a wider range of voltage supplied so that you can go all the way up to 32V max. The second board all has smd with a better DAC with 4 outputs and ADC with 8 input and micro with more ports so you can put more in/output stuff on it and use the digital board for other projects as well. Oh and another option is to make this board a Arduino shield board so you don't have to fight to program the controller.You know were I am going with this and that is to allow a dual voltage power supply...I was going to do this so I have already picked out some smd parts, let me know if you want to know what I came up with.Rutger

author: PeteInTexas
author_rank: Frequent Contributor
timestamp: February 13, 2012, 07:09:49 am
content: Quote from: EEVblog on February 13, 2012, 06:16:55 amPresumably, the goal of kits is to be instructive. I personally learned more about electronic principles by studying kit schematics and researching what I don't understand about it than from the act of building the kit itself. I mean, its not like you're learning by trial and error or experimentation when building a kit.So if you ask me, go with an assembled smd board especially if its cheaper. If a hobbyist is serious, there will be plenty of other opportunities to learn how to solder.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 07:56:58 am
content: Quote from: Rutger on February 13, 2012, 06:58:12 amAlready done that actually. Two software selectable ranges, 0-10.24V and 0-20.48V.QuoteI don't know if I would go that far in this design.Dave.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 07:59:47 am
content: Quote from: PeteInTexas on February 13, 2012, 07:09:49 amYep, that's exactly what I'm thinking.If the kit doesn't save any cost, then might as well supply the board fully assembled, and indeed might be cheaper which will be good for everyone.The instructive nature is in all the videos I'm doing, and the open source nature of it that allows playing around.Dave.

author: Harvs
author_rank: Super Contributor
timestamp: February 13, 2012, 08:14:25 am
content: Quote from: EEVblog on February 13, 2012, 07:59:47 amI was thinking that if I got one I'd by linking the uC socket up to another board to put an ethernet enabled part in (like maybe a PIC32 or ARM). So it would be good if the uC wasn't SMD, or if we had the capability to de-solder the SMD part and use some headers to access all relevant signals.Just my take...

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 08:20:27 am
content: Quote from: Harvs on February 13, 2012, 08:14:25 amFor the Ethernet part I was simply going to add expansion connectors for the WIZnet module. Impossible to beat for price and simplicity.Dave.

author: markus_b
author_rank: Regular Contributor
timestamp: February 13, 2012, 08:26:42 am
content: Quote from: EEVblog on February 13, 2012, 07:56:58 amThis is the most important simple modification you can make to increase your potential market. 10V is just a tad low for quite a few applications.Though-hole kit or SMD built PCB does not matter much for me. There is one thing though: In a through-hole kit it is easy to add a small, private mod. For example I'm thinking to add the transistor and LED back in, who show that it is in current-limiting mode in hardware. I like a dedicated LED for that function. It would be good if the SMD version PCB had all signals available somewhere on a pin. You don't need to fit the pins, just have them there. This increases the board size again, but I care more for modd-ability than for small size.But before deciding it would be nice to listen to your story till the end. Things like the case do matter too (will it be part of the 'kit' ?). I would like to be, making a case is often a pain.Markus

author: Magicmushroom666
author_rank: Contributor
timestamp: February 13, 2012, 08:30:17 am
content: If both built and kit versions were in the store, I think i'd buy which ever one was cheaper! If prices were the same i'd prefer the kit version, but i'd certainly not pay more money for a kit one when an alternative was available.

author: markus_b
author_rank: Regular Contributor
timestamp: February 13, 2012, 08:57:15 am
content: Contrary to others I think the AVR can be a SMD device. People who are likely to brick it would be shielded by the Arduino environment, who uses it directly is likely to know his way around.If someone wants to use another micro, then they better create a new PCB for it too.Markus

author: Harvs
author_rank: Super Contributor
timestamp: February 13, 2012, 09:06:45 am
content: Quote from: EEVblog on February 13, 2012, 08:20:27 amYep that'd work fine to. Do the WIZnet modules you're talking about have uSDCARD sockets? I've just got a Freetronics ethernet board (with WIZnet chip) and having the bulk storage is great for serving up pages based on raw html, css and filling in the realtime data with AJAX requests. Nice and fast considing it's only an 8 bit uC.It needs the 32k part though, the demo html server from adafruit (I think) takes up 21kB of program space.

author: Unknown
author_rank: Unknown
timestamp: February 13, 2012, 09:10:56 am
content: Quote from: EEVblog on February 13, 2012, 06:16:55 amThis isn't going to be the kind of kit someone would buy as a soldering trainer so I'd say the SMD option makes more sense. Likely longer lifetime for parts, smaller size, more reliable, (less nobs blaming your design for their absence of skill).Perhaps though if you were to go this way you could consider incorporating a fair few connection and cut points in the layout so the kits still lends itself to easy modification by those who want to go further than assembly by the numbers?My 2 bobs .....

author: electrode
author_rank: Regular Contributor
timestamp: February 13, 2012, 09:12:16 am
content: Quote from: markus_b on February 13, 2012, 08:57:15 amThis is true. I'm not really phased either way. More curious about the 2nd board/secret feature that we're still being taunted with. :p

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 10:48:18 am
content: Quote from: Uncle Vernon on February 13, 2012, 09:10:56 amYup, been there, dealt with that before.QuoteYup, that would be a given I think.Dave.

author: thilo
author_rank: Regular Contributor
timestamp: February 13, 2012, 11:43:59 am
content: Quote from: EEVblog on February 13, 2012, 06:16:55 amHi Dave,as far as I understand the power supply project, it's about how a professional engineer turns a project into reality. And iirc one of the design goals was through-hole, because you wanted a kit, right? Shouldn't you have checked the cost of pre-soldered SMD vs. self-assembled through-hole before you choose all parts according to their availability in through-hole casings? And before you've gone through two revisions of a board for these through-hole components? You've already invested a lot in the through-hole kit, time and money, and I can't really understand why you make such a drastic change in your design, so late in the game. And what's bugging me even more, why didn't you check the cost before you went through all that work? You're a very experienced engineer, which you've proven over the years again and again in your blogs and especially in your power supply series. And that's why I just can't comprehend this sudden and drastic change. I'd expected that you would've checked this up front and can't really believe that you didn't. Especially because you so often talk about production cost and what possible cost factors are and then all your (recent) blogs about the cost for kitting something up vs. shipping it pre-soldered.I guess you're already on finishing the blog where you address your reasons for this fundamental change, so don't feel forced to answer it here againthilo.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 12:34:23 pm
content: Quote from: thilo on February 13, 2012, 11:43:59 amYes, and no. It's how a professional engineer develops a hobby project for their own enjoyment, based on many whims that change often.QuoteCorrect, that's what I originally wanted.QuoteI already know that a through-hole kit wouldn't save much, if anything, and may in fact be limiting the design in various ways.I did it because Iwanteda through-hole kit, not because it was the best or lowest cost option.I became kind of infatuated with the kit idea at the time.I now possibly changing my mind. That's allowedQuoteDrastic?It actually won't cost me a cent, because I have to re-spin the board anyway. All it will cost me is a day or two tops to lay out a new SMD version of the board, no biggie. My existing boards and proto parts can still be used to build up functional units, so no waste.QuoteYou don't get it. It's not about getting something "right" up front, as there is no "best" or right solution for these types of personal projects. It's about having fun on a personal pet project and seeing where it goes and very often changing your mind on a lot of things. I wanted a kit because I thought that would be kind of cool, like I've done many times in the past, not because I methodically went through the sums and deemed that was the best option.A "drastic" change would be changing the architecture completely or functionality in some big way. Just changing from through-hole to SMD is fairly trivial and actually costs nothing.I didn't suddenly realise today that "OMG, I can't believe that an SMD assembled board will likely cost the same as a through-hole kit". I knew that was likely.Just some discussion with the assembler today was the catalyst to get me to re-think my infatuation with the kit idea.The project has morphed and changed in many ways, and in many ways you haven't seen on the blog. And those changes are often done on whims, simply because I want to, not because it's the "best", cheapest, simplest, or whatever option.Dave.

author: markus_b
author_rank: Regular Contributor
timestamp: February 13, 2012, 12:57:45 pm
content: Quote from: electrode on February 13, 2012, 09:12:16 amI think these are two distinct items. It looks to me like Dave had this one, specific use scenario for a power supply with built-in ucurrent adapter. Something like 'I want to measure/the power consumption of this microcontroller in all sleep modes' and found he is missing the ideal power source for that and then decided to build it.The 2nd board is just there to defer decisions about PC interfaces to later, but keep the options open. I think.

author: caroper
author_rank: Regular Contributor
timestamp: February 13, 2012, 03:31:53 pm
content: Just to add my 20c worth (that is 2c A$ at the current exchange rate) I am 100% behind a populated smd board rather than a kit. The presence of any smd in a kit was enough to scare off many, myself included, and yet I am working with and designing smd boards. I just have them assembled by people who have the skills, tools and eye sight to do it properly.What I would like to see is a bare bones offering of just the populated board.If I could buy 2 boards and then interface to them to my own front end cpu, display and control panel (each board still retains its own dedicated cpu, I am adding a 3rd) I could have a dual supply with the features I want and save the shipping costs of the heavy hardware (case etc.) that I don't require.As others have pointed out the real educational value is in the tutorials, not the assembly, and I certainly don't think this possible change of direction invalidates the series. I think it increases the educational value. Often in life you will have last minute change of mind coursed by many external factors, not often driven by cost but by user requirements.Dave is showing us such a situation is handled and it is an invaluable lessen.

author: toddisbn
author_rank: Newbie
timestamp: February 13, 2012, 04:13:01 pm
content: IMHO, the kit concept is great for not only beginners to learn to solder etc, but here are some points that may or may not have crossed your mind.Being a kit you have the pride of something you have made yourself.If the assembled kit does not work then there is a fantastic opportunity to post the fault of the forum and have other help you diagnose the problemAs thru hole, you can repair the unit a little easier, source part from dse, jaycar etcMods will be easier, if they entail soldering on the board, or replacing partsUpdates to the DACs and ADCs will be something joe blow will stand a chance at doingIf Joe blows a track, he stands a better chance with typical TH boardsLayout is most already done for thru hole... People following at home have enjoyed the journey so farThe project shouldn't have to cover all bases. This ain't for NASAYou will still need thru hole components on it anyway (less space saving)You will still need the meaty traces (less space saving)As preassembled you are competing with other premade units on the market placeSo just a few ideas. However I am not totally against a prebuild unit. It just that the best tools you can have at times are the ones you build yourself. I have noticed that Dave has several kits built from companies like Altronics etc (PSUs)One final thought.Above mentioned suppliers have abandoned the market, they have typically used designs from EA, ETI and SC, supplied them until sales go down then ditch the kits ASAP. I would rather buy kits from the bloke that designed the circuit and saw the project to a point where I can purchase it. Not at any stage do you see a supplier of kits who may provide a rev B and update the kit to reflect the changes that occur to the designer after the article is originally published.Dave this is an opportunity to firmly place yourself in to the re-emerging electronic hobbyist market, and have your fans support you by buying a quality kit which I am sure will prove invaluable on any geeks bench.Yes I will buy it, if it only comes as a preassembled unit, however I would like to see it as a kit.

author: Unknown
author_rank: Unknown
timestamp: February 13, 2012, 08:41:38 pm
content: Quote from: EEVblog on February 13, 2012, 12:34:23 pmAs opposed to commercial projects where specs are determined in advance and never changed after that point, right?I don't think there's that much education in soldering a kit together, except to learn to solder which you might as well with the LED christmas tree kits. The amount of troubleshooting for many people is probably going to be limited to emailing you or posting on the forum that the kit doesn't work, that they did everything right, and that they don't own a DMM to test it. Might as well go with SMT if you can get a cheaper / better product with less hassle.I think the dozen or so videos you will have by the time it's shipping should offer plenty of opportunities to learn. They describe both the theory of operation and the design process. This is much more valuable than learning to solder the 10 k resistor in the holes labeled R4.You might choose to let the customers assembly the through-hole components like connectors if this would save you a significant amount of assembly fees. This is howELVoperates. In most of their kits, all SMT components are pre-assembled, but TH components are not.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 08:53:49 pm
content: Quote from: alm on February 13, 2012, 08:41:38 pmYes, and that is the fear, which I have experinenced many times before.If it doesn't work because they screwed up, I will often cop the support emails, or in some cases I've had kits returned in the post with a note saying "your kit didn't work, fix it."QuoteYes, that is another option.Dave.

author: WBB
author_rank: Regular Contributor
timestamp: February 13, 2012, 09:10:29 pm
content: Quote from: toddisbn on February 13, 2012, 04:13:01 pmVery well said. I also enjoy building things myself. I get a much better understanding of how things work in doing so. Obviously I'm voting for the TH kit.I do understand that selling a kit is more troublesome from a support standpoint, but there is a great community here to help with that. Besides, goofing up a few wires on an smd kit is going to happen as well. Nothing is idiot proof.I have really enjoyed the series. Quality kits are hard to find these days at all. Seeing one developed from the beginning to its present state has been very educational and as always, entertaining!Ultimately Dave should release it in the form he is most comfortable with. A kit gets my vote but I do understand the ramifications of a rather complex kit. Either way, kudos for the excellent work thus far on the ps and the blog in general.

author: Makezilla
author_rank: Newbie
timestamp: February 13, 2012, 09:24:20 pm
content: From an education perspective I think the TH board has some great advantages because it gives us the ability to 'play along at home' with the superb video content. Sure you can probe the SMD board, but that process is much easier with TH components (well, for my aging eyes it is anyway). And if the assembly doesn't go quite right and it doesn't work the first time, even better. The kits I have learned the most from are the ones that I messed up on the first time through.

author: EEVblog
author_rank: Unknown
timestamp: February 13, 2012, 09:31:15 pm
content: Quote from: WBB on February 13, 2012, 09:10:29 pmYes, very true. Unless it's fully assembled and tested, which I don't really want to do.QuoteThat was one of the reasons for doing a kit.Dave.

author: WBB
author_rank: Regular Contributor
timestamp: February 13, 2012, 10:30:45 pm
content: Quote from: EEVblog on February 13, 2012, 09:31:15 pmHere in the US, even that is not foolproof. Our idiots can be rather ingenious.QuoteI, for one, hope it makes it to reality.

author: george graves
author_rank: Super Contributor
timestamp: February 14, 2012, 01:30:08 am
content: Dave - just a thought: In the next blog, can you go over the changes that you've made, and what the current specs are? I've honestly gotten a bit lost.I *do* love this series. Any chance we can get a sneak peek at the case?

author: sacherjj
author_rank: Frequent Contributor
timestamp: February 14, 2012, 04:37:10 pm
content: I personally think the right idea is this:All design that can be SMD done that way and assembled, with exception of the processor. Or, if the processor is SMD, allow header for connections so it could be desoldered in a hack and the header used for possibly joining multiple boards. Like many, I think this would be a great board to hack into a dual polarity supply or something else.The users would solder the through hole pieces, LT3080, heatsink, encoders, headers, power jack, etc. (possibly MCU).This keeps your assembly costs lower (I assume all SMD is much cheaper than SMD plus through hole.) Keeps the kit with non-intimidating pieces. And greatly reduces part count to be put together for the kit.There is one other thing that I love with the SMD design. I would venture to say that many more people have done work with through hole than SMD. We have a board design that you have done with through hole. It will be cool to see how layout techniques and look changes for SMD. I'm currently learning how to make that change after laying out TH boards for decades and getting into SMD. I would be able to take a look at the SMD board and compare it to previous TH versions and see what needs to be changed, what is harder, what is easier. etc. So the change midstream is actually very instructive.

author: robrenz
author_rank: Super Contributor
timestamp: February 14, 2012, 04:54:33 pm
content: Quote from: sacherjj on February 14, 2012, 04:37:10 pmI like that idea a lot. I was looking forward to doing a kit. Brings back memories of doing heathkit stuff when I was a lot younger. But this would lighten the workload on Dave and probably make the kit cheaper in the long run. I personaly would not mind the kit being all surface mount, but kitting all the parts probably cost more in Dave's time than having all the SMD stuff done by an assembler. If this kit is being done to be hack friendly I think keeping the MCU thru hole with a socket would be better.

author: metalphreak
author_rank: Frequent Contributor
timestamp: February 14, 2012, 08:52:27 pm
content: Dave: if you use AusPost'swww.clickandsend.com.auservice, you can fill in all the customs stuff online and just print out labelsYou should only have to fill out the package details once each time you do a batch. Just make sure "keep item details" tickbox is checked.You can even import data from an excel file.

author: dcel
author_rank: Regular Contributor
timestamp: February 17, 2012, 12:07:12 pm
content: QuoteFunny, I've been saying " There's no cure for stupid and you can't teach common sense!" for years. Lately, I have been adding, "You can't make it idiot proof, they'll just build a better idiot!"Its very unfortunate that it seems that a growing portion of the population is just dumb, and getting more so daily. Damn video games and rap music rotting their brains.Chris

author: markus_b
author_rank: Regular Contributor
timestamp: February 17, 2012, 12:20:00 pm
content: Quote from: dcel on February 17, 2012, 12:07:12 pmThe problem is that is getting socially acceptable to be dumb and for 'society' to bear the cost of being so. If caught being dumb you used to crawl into your hole and lick your wounds, now you try go become famous for it and to get a princess treatment.

author: rkoval
author_rank: Contributor
timestamp: February 21, 2012, 06:34:48 am
content: Speaking as someone that is trying to learn the basics, I plan on building up the basic non microcontroller design, then perhaps adding in my own micro preference later on. I may purchase the kit to have a nice polished unit to add to my bench.I find this process very educational. If I did purchase a board from Dave, i would also use it as educational. I buy test equipment, and other development boards that I have not touched over the years. I don't look at it as a waste of money. Its all for me to learn the topic of electronics. Whether its the design or build process. If I screw it up, I can try to fix it and learn some troubleshooting. It all make me better at what I love.I am a bit nervous about SMD, but I need to learn. That would be fine too.If I want something with a warranty, I will buy commercial. To me, that is not what a kit is.Thanks Dave for your hard work and valuable videos.Rich

author: Rerouter
author_rank: Super Contributor
timestamp: February 21, 2012, 07:05:33 am
content: also agreee that the kit shouldn't have warrenty, its about learning how it works, and being free to modify or combine into anything else,

author: storkbus
author_rank: Newbie
timestamp: February 21, 2012, 03:07:28 pm
content: Dave,I would buy the pcb, kit or device. I really like the design soap show your broadcasting about this powersupply. This is no precooked staged show. Every episode is a new cliffhanger. You really show the various iterations of a design process. People might finally understand that this is very difficult and labor intensive work.Now regarding the kit. As long as the microcontroller is socketed I'm fine. If people brick the powersupply and they can't repair it themselves they can simply buy a new chip from you. If you're not going to sell a functional and tested device I would prefer a mix of pre soldered smd components and diy TH components. This has been suggested by several other people before as well. I think it's a nice balance. And please don't go below 1206 size? And do add some extra or larger pads for testing/expansion/modification at relavant locations.Regarding the design what would be the response time of this PSU? I would like to program it so that it can output various voltages at specific moments for testing purposes. I want to simulate low battery and transients for various microcontrollers and sensors.Regards,Frederik

author: DarkPrince
author_rank: Regular Contributor
timestamp: February 21, 2012, 07:27:15 pm
content: Hey Dave,Just wanted to put in my comment on this. Either through-hole kit, smd pre-assembled, smd kit, or any hybrid is supported. I am very interested in acquiring a unit. I do plan on engineering my own at some point in time, hence why I don't mind any sort of version of this system. I am in dire need for a bench-top power-supply though, let alone the abundance of resource you have already provided during the development of this project. I thank you for your dedication, and hope to continue to have the incentive to support, and learn, from you.Craig

author: EEVblog
author_rank: Unknown
timestamp: February 21, 2012, 10:00:30 pm
content: Quote from: storkbus on February 21, 2012, 03:07:28 pmI haven't measured the response time, but it would not be quick. i.e. I doubt you'd get KHz out of the thing. The cap on the SET pin will cause issues here.Dave.

author: EEVblog
author_rank: Unknown
timestamp: March 24, 2012, 08:45:08 am
content: Quote from: metalphreak on February 14, 2012, 08:52:27 pmDamn, I'm now seriously considering using ebay as my online "shopping cart".Because it seems it integrates very nicely with clickandsend.com.auhttp://auspost.com.au/clickandsend/assets/pdf/eBay_Click_and_Send_step_by_step_guide.pdfPros:- Everyone knows ebay- Streamlined system- No shopping cart to maintain.- No more customs form, and a courier will even pick up the items if required.- No more waiting at the post office as they process each one item by item and getting the dumbest and slowest teller.Cons:- Have to print and sign three consignment notes and stuff in those clear stick-on packets - not as easy as my current single Dymo label.- The good'ol ebay/paypal double-dip fees.- Ebay is shit at keeping records, everything just vanishes after a few months.Essentially, the problem I have (and surely every small-scale Oz seller has?) is shipping stuff overseas via Australia post. Ebay integrated with click-and-send seems like a good solution to that.BTW, I can't just use clickandsend on it's own because AFAIK there are no shopping cart system that integrate with it, and it would crazy silly to addresses manually, or fiddle with getting excel import working and cross-correlating with stuff sent in the shopping cart.Thoughts?Dave.

author: electrode
author_rank: Regular Contributor
timestamp: March 24, 2012, 09:25:15 am
content: Groan, ebay. The main reason they can charge such huge fees is that everyone knows ebay; it's the go to place for searching for things.However, you sell kits and other niche electronics items. I would think you'd be found mostly by (1) YouTube and (2) by this site, so the main benefit you're paying for with ebay is just the clickandsend thing.If you sold a $100 kit on Ebay, you'd have $1-2 listing fee, $5 final value fee and about $4 paypal fees (depending on a few factors). 10% gone already. I'd avoid it.

author: T4P
author_rank: Super Contributor
timestamp: March 24, 2012, 09:27:26 am
content: All i want is the Gerber files for Dave Jones Rev C

author: markus_b
author_rank: Regular Contributor
timestamp: March 24, 2012, 09:36:50 am
content: Hi Dave,I don't really care about your logistics, just use what is best for you. I will want to use the lowest cost airmail, essentially as I want the entire cost (toy + postage) to stay below USD 80 or so, stay within the duty-free area. If goes above that I'll have to pay import duty, VAT and handling fee, adding another USD40.Also, it important that there is the green customs declaration (CN23) and that the complete invoice is attached to the packet in the clear plastic envelope. The invoice has to include everything, including postage fees. If it is missing customs open the package to verify the contents and charge you an additional special handling fee.I think this is similar in most other European countries.

author: EEVblog
author_rank: Unknown
timestamp: March 24, 2012, 09:56:54 am
content: Quote from: markus_b on March 24, 2012, 09:36:50 amI've never had an issue with simply the custom declaration on the front. And I've shipped to nearly every country on the planet.Dave.

author: markus_b
author_rank: Regular Contributor
timestamp: March 24, 2012, 10:07:36 am
content: Quote from: EEVblog on March 24, 2012, 09:56:54 amI've got plenty of packages with just the CN23 declaration with no problems. But I also paid more in customs fees than the worth of an item once I had a memory dimm send to me by my Sister in Germany because the package had only the CN23 sticker. YMMV.

author: SeanB
author_rank: Super Contributor
timestamp: March 24, 2012, 10:12:08 am
content: Fleabay is not good in ZA, you have a hard time with exchange regulations at certain banks ( I bank with one, they do nice cheques and those are accepted worldwide) so I would prefer to post a check to Dave and wait for the slip in the mail to collect at my local hub ( near to me, nice people there) and pay the duties.

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 24, 2012, 10:39:09 am
content: The integration with ebay is actually really nice. If you put in the dimensions for the item on your ebay listing, it'll also automatically import that into clickandsend. Unfortunately for overseas stuff it won't let me pay online and then take it to the post office. So you end up with the person entering in all the details anyway, but atleast you get the address and customs stuff pre-filled out which is handy. I'm not sure how the courier pickup stuff works. Once you pay/process items, it automatically links back to ebay and marks those items as sent as well as recording any tracking numbers.Regular Airmail - 2 copies of the label - 1 for the package, 1 for yourselfRegistered International - 4 copies of the label - 1 for package, 1 for customs, 1 for AusPost to keep, and 1 for youeBay fees may seem high, but it can be well worth it if you consider how much time you save. A $19.95/month Basic Store subscription gives you access to 30day Fixed Price listings which are only 40c (and include the gallery pic). Usually you only get 14days. Fees are lower for items >$75 (7.90% of the initial AU$75.00 plus 5.00% of the remaining closing price (AU$75.01 to AU$1,000.00)). You also get a free subscription to Selling Manager Pro which will let you print basic invoices automatically.You need to work out how many you'll sell to determine if a store is worthwhile. You could always just try it for a month to see how it goes. Maybe only do it whenever you have a new batch of products coming in.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 24, 2012, 10:58:01 am
content: Having proper paperwork attached to the package really helps to get fast customs clearance and keep the cost down. A complete CN22, a copy of the invoice (itemized), both with plausible, honest figures, and with the mentioning of the TARIC number do tend to keep the bureaucrats happy. It can make the difference between a week or two of hassle or a 30 second customs clearance.eBay? Well, I do hate PayPal (IMHO the worst scamming part of eBay) but if it helps to sell the kit ... I don't think other companies will be much cheaper. Running your own shop system is also a lot of work, and renting a shop system and service with all the necessary features is again not cheap.

author: Tooms
author_rank: Unknown
timestamp: March 24, 2012, 11:29:23 am
content: Quote from: markus_b on March 24, 2012, 09:36:50 amdamm your lucky...Here in Denmark we have the duty-free limit at 80 DKR(Danish) and 80 DKR is around 14,3$So this means that if we buy some thing from outsite EU and the value WITH SHIPPING is more then 14,3$ then it will look like this.Let say an item to 25$ and shipping cost of 5$Item cost = 25$Shipping = 5$25% tax of the 30$ = 9$Tax handling fee = 21,4$So that is an total of 60,4$ for an item costing 25$

author: metalphreak
author_rank: Frequent Contributor
timestamp: March 24, 2012, 11:53:41 am
content: In Australia, we don't get taxed on anything less than $1000... Even so customs isn't all that strict on enforcing it either.

author: markus_b
author_rank: Regular Contributor
timestamp: March 24, 2012, 03:27:07 pm
content: Quote from: Tooms on March 24, 2012, 11:29:23 amThe precise regulation here is that they don't collect the TVA, if it is below CHF 5 (slightly more than USD 5). The TVA is 8%, so the limit is around 65, actually. Looks like the USD gained ground since I calculated it last autumn. I don't mind to pay the TVA, it is not that high, but they add a handling fee of CHF 20 and deliver the stuff by COD where the post office adds another COD fee, so the fees add up.