POLL: New µCurrent Design - Page 1
Forum section: electronics / projects

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 12:38:09 pm
content: I'm back onto the µCurrent again, and have been thinking...I have shown the new µCurrent GOLD versionIt performs better and looks better than the previous version, but there are several issues as I see it:- It is costly, more expensive than the previous version.- It still needs test leads to work with your meter- To replace the batteries you have to unscrew the box as before.Given that it's essentially a seldom used multimeter adapter I'm thinking of going back to my original idea way way back and have it as a simple bare board direct plugin for the multimeter, something like this:http://jaanus.tech-thing.org/category/half-ohm/But it will look better than that and will still use gold binding posts for the inputs on the top end, but of course plugs directly into the meter with integrated 4mm posts, and no case, kinda like that shown above. Powered from the old CR2032 instead of the proposed 3 x AAA's on the uCurrent GOLD.The 3 way switches give way to lower cost SMD 0.1" pin headers and jumpers for range selection and power on.The idea being that it becomes more of a pick it up and whack it in kinda adapter, rather than dick around with leads, and potentially have the up up and change that battery because you left it on a month ago.Rough estimate is that this approach drops the manufacture cost by about 40%. Giving better performance at less BOM cost than the old design. The uCurrent GOLD as it stands gives better performance at greater price. That doesn't necessarily translate into a 40% reduction in retail price, but it can of course be significantly cheaper than the current proposed design.Opinions?

author: BravoV
author_rank: Super Contributor
timestamp: October 01, 2013, 12:44:35 pm
content: Please explain further on the "better performance" part.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 12:53:34 pm
content: Quote from: BravoV on October 01, 2013, 12:44:35 pmI've changed the opamp to the AD8628 which gives a significantly better AC performance to 30KHz, and 0.05% resistors for the gain and low ranges (down from 0.1%), and an expensive 0.1% (down from 0.5%) high current range shunt resistor. The uCurrent gold could go to +/-1.4A (up from approx 300mA) by using a third different connector.This low cost one would use the same connector as the old design and use jumper pins for range selection which should be able to handle the same current.So the spec is now so good, it's actually a bit tricky to get commercial test gear to verify it.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 01:51:33 pm
content: Quote from: wilfred on October 01, 2013, 01:43:07 pmBecause you may not be able to find your banana-banana leads so easily when you need to go use it.Also, being less fuss means it may go from seldom used to more frequently used if you can just plug it in with no fuss.QuoteIt's not much more expensive to go to my my old design of 0.1%/0.5% accuracy.DIP is just dicky IMO, SMD is a lot nicer.I can still sell just the PCB for the SMD version.

author: Codemonkey
author_rank: Regular Contributor
timestamp: October 01, 2013, 01:53:11 pm
content: I'd buy one, but I'd much prefer switches rather than annoying fiddly jumpers!

author: Lightages
author_rank: Unknown
timestamp: October 01, 2013, 02:10:27 pm
content: I think you need another poll option, "other" .The thing about buying a piece of test gear is that it should be reliable as one of the biggest requirements. In other words it should not be fragile. I see a bare board design as being potentially fragile and if made as small as the example device shown in the OP then it would also be easy to misplace.I also agree that little jumpers are going to be a pain and it is inevitable that one will get dropped and disappear into the black hole on the floor of missing things that get dropped.Now take my opinion with more than just a grain of salt, I probably won't be buying one.One last thing.... The uCurrent Gold has only been revealed in the supporter's lounge as far as I know so the responses here might be limited or confused.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 02:11:58 pm
content: Quote from: Codemonkey on October 01, 2013, 01:53:11 pmUnfortunately it's not easy to get small PCB switches rated into the AMPS range.Also, I'm kinda salivating at the thought of pin jumpers, because it means I can build a nice automated jig where I can just plug the board into some mating header connectors. That kinda of stuff can help further reduce the cost.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 02:15:11 pm
content: QuoteThere is no other optionQuoteI did show it in the live video show.

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: October 01, 2013, 04:46:49 pm
content: I like the idea of plugging straight into the DMM rather than requiring another set of leads. But I feel less sure about a bare board. This is the other side of the half-ohm:.Insertion and removal may take a bit of force, and I'm going to want to grab it by the big sides, not baby it with the PCB edges. The battery side you show would be fine, and you can even see his is covered in fingerprints. But I don't think I'd feel comfortable grabbing the component side like that, applying force and grime to precision analog components.Can you give me something solid to hold on to and force around?

author: TrickyNekro
author_rank: Frequent Contributor
timestamp: October 01, 2013, 05:18:50 pm
content: I guess there is no extra room to install a switch to select the range, or can you squish it in?Also, full heat shrink protection would be nice, but yeah, sure enough not really easy to do,as you might need a cut away for the range selection and the battery.Apart from that, it looks cool sexy and practical.Btw, because of its size, maybe it would be nice to add a hole or something so it´s easy, if somebody wants to,to strap it with a cord somehow to the multimeter. You know, benches can get messy and it´s small and all the stuff!Best Regards,Lefteris, Greece

author: Fsck
author_rank: Super Contributor
timestamp: October 01, 2013, 05:26:04 pm
content: I like the plug idea, but it needs to be bigger and more structurally sound.In the same style as:Addendum: not the same size as the above, but a tiny <1 in^3 moulded case would be nice.

author: pickle9000
author_rank: Super Contributor
timestamp: October 01, 2013, 05:57:51 pm
content: I'd say go with the smaller design although I know others would always go for accuracy over anything else. I would think that a couple of screw holes on opposite sides of the pcb would allow users to armor up the little guy with anything from a chopped up SDCard case to a couple chunks perfboard. As for jumpers it is what it is, if lost buy a bag of em off ebay no big deal. Also consider placing the pins in a configuration that would support a daughter-board that could hold switches (for those who want to muguffy it).

author: free_electron
author_rank: Super Contributor
timestamp: October 01, 2013, 06:25:06 pm
content: why don't you put it in the kind of case i used for the JW pulse generator. have two banana females on one end, two banana males sticking out the other end at 3/4 inch pitch.the case can be optional for people that don't want it.Think about what fluke did with their thermocouple adapter. it plugs straight into any multimeterthe case i used for the JW pulser is small enough it doesnt block any controls from multimeters , whether bench or handheld.and that case is cheap.see belowi used the case and two bare metal keystone female banana's. i'll send you the altium document, it has the correct step files in em as well as the board contour. plug and play.

author: free_electron
author_rank: Super Contributor
timestamp: October 01, 2013, 06:27:40 pm
content: drat. PM doesnt allow attachment. here it is :

author: free_electron
author_rank: Super Contributor
timestamp: October 01, 2013, 06:54:19 pm
content: inside viewthe slots in the pcb allow the connectors to drop in sideways. they are soldered on both top and bottom layer all along the length of the connector.this makes it mechanically very stable.you can use a surface mounted cr2032 coincell holder. a thru hole slide switch allows on/off and range selection.connectors used :keystone 575-8 for the female solid metalkeystone 552-4 for the males.

author: Lightages
author_rank: Unknown
timestamp: October 01, 2013, 09:02:05 pm
content: If the new uCurrent could be built in that housing, I would upgrade. But... It would have to have switches, not easy to lose jumpers.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 09:37:15 pm
content: Quote from: free_electron on October 01, 2013, 06:25:06 pmYes, but this adds the need for a machined thing which adds cost. Also, I want binding posts, so they have to either extend from the open end if they screw into the boards (the way to go is some people want bare board), or mount on the back panel and have wiring, adding the manufacture cost.I'll look into it though, thanks.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 09:42:42 pm
content: Quote from: free_electron on October 01, 2013, 06:54:19 pmI was going to have PCB prongs that extend out into the hole in the back of the banana plug, which holds then in place better for soldering.QuoteHow do you hold them in place while soldering?Seems fiddly, that adds cost and variability in production.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 09:50:15 pm
content: Quote from: free_electron on October 01, 2013, 06:25:06 pmPart number?There is machining cost as well, plus the fact the user will still have the open the case to change the battery each time.Any PCB slide switch will need to take 1.5A minimum.

author: ovnr
author_rank: Frequent Contributor
timestamp: October 01, 2013, 10:03:40 pm
content: That case looks likeHammond's 1553 case, probably the smallest version (1553AABK/1553AAGY for black or gray, respectively). They're very nice cases.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 10:08:00 pm
content: Quote from: ovnr on October 01, 2013, 10:03:40 pmUS$3.53 in volume + machining (which IIRC Hammond are not cheap at)I think we've just blown out the budget back to the original design.FYI, the old case is AU$1.08 in volume and made in Australia.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: October 01, 2013, 10:11:48 pm
content: Definitely not jumpers.Even it it means an extra socket.I'm sure you must be able to find a suitable switch - what's wrong with the ones you used before?Remember if you need a bit more rigidity, 2.4mm PCB would be an option.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 10:46:53 pm
content: Quote from: mikeselectricstuff on October 01, 2013, 10:11:48 pmOnly 350mA rating. Not good enough for the 1.5A current range. that is why the new uCurrent GOLD used 3 input binding posts instead of two, no need for the high current to go through a switch.

author: free_electron
author_rank: Super Contributor
timestamp: October 01, 2013, 11:08:37 pm
content: i'd gladly pay 5$ more if it sits in a nice box.The slide switch can be an ALPS or APEM. i'll post a partnumber.Leave machining to the end user. they can drill 4 holes. it aint that hard.if you want the banana with screw and sidewise hole terminals i'd go with a 7006 style (7007 for black)http://www.keyelco.com/category.cfm/Plugs-Pins-Jacks-Sockets/Binding-Posts/p/459/id/462i used those keystone bare metal female bananas a lot. if they are soldered sidewise they will not move.since the PCB sitss off-cente rin the housing vertically : you make the opening in the pcb 1 mm smaller than the width of the body. this has the net effect the terminal falls in the slot nicely and aligns itsel. tack it down topside , flip board over , solder it down bottom side.you can sell the microcurrent board preassembled , apart from having to solder the banana terminals yourself and drill the 4 holes. even if you 'mis-drill' the holes the collar on the bananas will cover flaky handywork and you won;t see it at all.

author: EEVblog
author_rank: Unknown
timestamp: October 01, 2013, 11:13:49 pm
content: Quote from: free_electron on October 01, 2013, 11:08:37 pmYou forgot the slide switches and LED.Labelling?This approach is getting a bit messier than my old uCurrent design.

author: dannyf
author_rank: Super Contributor
timestamp: October 01, 2013, 11:32:42 pm
content: QuoteMost times, those parts are designed to meet the following top goals: looks, looks and looks.

author: Zad
author_rank: Super Contributor
timestamp: October 01, 2013, 11:38:00 pm
content: If you made it a fixed range unit, you could make a whole set of them. People would then inevitably buy several of them, they would be easy to calibrate, more robust and cheaper to build. Oh yes, and more profitable. It might also make it easier to move to a transimpedance amplifier design with zero burden.

author: EEVblog
author_rank: Unknown
timestamp: October 02, 2013, 01:15:54 am
content: Quote from: Zad on October 01, 2013, 11:38:00 pmI had that fleeting thought...

author: EEVblog
author_rank: Unknown
timestamp: October 02, 2013, 01:49:51 am
content: A solution could be to simply leave the top half of the case off, and just use the bottom. Effectively just like the old design uCurrent. The screws hold the PCB in place, the battery (top side) can be removed without undoing the case, and the switches and LED are accessible on the top side along with PCB labelling.Yet it would still have a bottom to protect the components and provide some grip for handling.Too bad the Hammond case lip isn't lower to the PCB level or below, but spacers could be used perhaps.I've considered this a long time back and these cases are pretty nice for this purpose:http://www.altronics.com.au/download/ndb/specifications/h/H0212.pdfRemovable end panels allow connectors to protrude without holes

author: free_electron
author_rank: Super Contributor
timestamp: October 02, 2013, 02:37:20 am
content: Quote from: EEVblog on October 01, 2013, 11:13:49 pmlabeling is not an issue. you use one red and one black terminal. the output is in line with input so no markings needed there.led is a hole inbetween the input bananas.switch is not an issue. when i did the JW pulser i lasercut (makerspace) a piece of plexiglass with the position for the led and the slit for the switch. this plexi slid in place over the internal screw posts.i have a very simply column drill with an x-y screw-vice. put in a milling bit and 20 seconds cuts you the slit. the plexi is your guide.

author: EEVblog
author_rank: Unknown
timestamp: October 02, 2013, 03:14:38 am
content: Quote from: free_electron on October 02, 2013, 02:37:20 amThe range switch needs labelling.QuoteThe regular Joe isn't going to be able to cut their own switch slots.

author: Stonent
author_rank: Super Contributor
timestamp: October 02, 2013, 03:26:14 am
content: New idea. uCurrent uWatch!Just put it all together!

author: ElectroIrradiator
author_rank: Frequent Contributor
timestamp: October 02, 2013, 05:38:26 am
content: I vote for an encased design of reasonable mechanical strength, preferably a plug-in design.

author: bookaboo
author_rank: Frequent Contributor
timestamp: October 02, 2013, 08:05:44 am
content: I liked the old style just fine- The case adds practically zip to the cost- If battery life is an issue just adda 2way header in parallel, people can hack in their own bat pack inside the case.- "Not having leads" isn't that big an issue, I just keep mine in a small box with leads.- I see mechanical stress issues if it's made to plug direct to multimeters. Over time those connections will get worn with wiggling to connect and disconnect.

author: tld
author_rank: Regular Contributor
timestamp: October 02, 2013, 02:29:15 pm
content: Biggest challange with µCurrent has often been price and availability. Other than that, formfactor is less important. If it's be possible to get "something" below AUS 30-35, that'd be below some customs-limits, which really change pricing. Effectively, costing AUS 36 will often be 50-100% more expensive than costing AUS 35.I know I might be asking a lot, but having a version below that price-point (below AUS 30 for safety against currency-fluctuations) would make it a no-brainer to buy for a lot of us, while it's a medium expense now.Even if it's just the bare PCB, bare PCB with hard to get parts, or complete kit.

author: TMM
author_rank: Frequent Contributor
timestamp: October 02, 2013, 02:41:51 pm
content: The only issue i have with the rev3 design is the current input terminals. If the threaded section was a little longer it would make them a bit better to use with deep shrouded banana plugs and crocodile clips (yes i know, bad habit using croc clips in banana jacks...).I am quite happy with the rev3 form factor and you could easily fit a beefier switch for higher current. Jumpers are for 'set and forget' configuration, not the main range switch on test equipment imo.I'm all for the plug-in idea with the existing form factor or smaller as long as it doesn't compromise on features/accuracy.

author: free_electron
author_rank: Super Contributor
timestamp: October 02, 2013, 03:18:25 pm
content: Quote from: EEVblog on October 02, 2013, 03:14:38 amNot if you make it fixed range.On off and range could be 1 switch. Those slide switches have two sides with three notches each. Use one side for power, one for range.You would have to mill the slot. I did that too for the jw pulser.

author: veryevil
author_rank: Unknown
timestamp: October 02, 2013, 07:47:21 pm
content: Hey, this sounds really interesting.I've got 2 uCurrents and the one big issue I have with them is the limited range being tied to the 3v battery +- 1.5v I often find it clipping. I see the new chip is still only +- 2.5v max is there a similar chip that has a higher input voltage range allowing much larger range?

author: AG6QR
author_rank: Frequent Contributor
timestamp: October 02, 2013, 11:02:19 pm
content: I've got an original classicuCurrent, and am unlikely to need another, so I'm not a likely future customer. That said, I want to be able to throw the device in a drawer or toolbox along with a bunch of other devices and not worry about it until I need it. So I'm not crazy about a PCB with exposed parts, contacts, and traces that could be subject to ESD damage or could be damaged by shorting out. Also, I really prefer switches to jumpers. I might accept a jumper on the condition that the jumper is ALWAYS installed on some set of terminals, so it can't be easily misplaced. But I'd complain about it.My preference, in order:A smaller, fully enclosed case that plugs directly into the meter, similar to the common thermocouple adapters shown earlier in this thread.The original classic design.A small, bare PCB that plugs directly into the meter, similar to the resistance adapter shown in the first post.In other words, I value having a full enclosure around the electronics more than I value miniaturization.I like the originaluCurrent packaging. I'd prefer to omit the binding posts and have the inputs be banana jacks like the outputs are. The binding posts are bulky protrusions, and since I always end up plugging banana plugs into them, the bulk is a waste as far as I'm concerned. Ideally, I'd like shrouded banana jacks, so I can easily use the same probes I already use with my meters. But unshrouded banana jacks, just like are currently used on the output side, would be an improvement for the input side, in my book.As for cost, I think the original design was a fair value. If a bare pcb version were around 60% the cost of the original, it would be tempting. A version in a "thermocouple adapter" style plug-in case would be worth maybe a 40% premium over the original design. On any version, I think the difference between a jumper and a switch is worth around 20% or 30% the total price of the device.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 12:22:42 am
content: Quote from: free_electron on October 02, 2013, 03:18:25 pmI don't want to mill anything.I am trying to make it simple and reduce costs, these aren't low volume one-off's here, stuff like that adds up in production. I'd go back to the old design before I have to mill slots in stuff.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 12:25:05 am
content: Quote from: AG6QR on October 02, 2013, 11:02:19 pmWhat about a plug-in enclosed bottom that protect the circuits, but an exposed top that has the battery, switches, and labeling? Just like the old design, but with battery on top?

author: free_electron
author_rank: Super Contributor
timestamp: October 03, 2013, 01:16:11 am
content: Quote from: EEVblog on October 03, 2013, 12:22:42 amah. ok. I thought you were going to make a more upscale version. i saw the 'GOLD version' in the inital post and assumed that this was the gold version, but apparently you want to make an economy version now. my mistakeI'd like to have one similar to what i proposed. Simple box , plug it in between meter and cables. Nice looking and well built. I'd spend 10$ more on a 30$ microcurrent if it sat in a box like i've shown with icely milled holes and slots. I'm not fond of bare boards, protruding stuff you can touch.. but that's personal taste and not what you are after .Still it may be worth investigating what a company would charge to machine the plastic for you. It may not be that expensive in quantity.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 01:21:36 am
content: Quote from: free_electron on October 03, 2013, 01:16:11 amIt is unfortunately, unless you want to go to deepest darkest parts of china. Hammond will machine and silk screen their boxes for you, but it is far from cheap.

author: AG6QR
author_rank: Frequent Contributor
timestamp: October 03, 2013, 01:49:06 am
content: Quote from: EEVblog on October 03, 2013, 12:25:05 amI'd be concerned about the possibility of shorting out the battery if it were exposed. Imagine throwing the device in a toolbox full of screws, nails, wires, and other conductive metal objects of various shapes and sizes. If you can guarantee that there's no danger of a short circuit, I'd think the design you're proposing would be an improvement over the original design.Realistically, I wouldn't abuse the thing that badly, but I might want to store the device in a drawer that might contain a test probe or two, with some exposed metal. I can also imagine a small thing like that occasionally being carried in a pocket along with car keys and change, not that I'd personally try such a thing.

author: george graves
author_rank: Super Contributor
timestamp: October 03, 2013, 01:51:32 am
content: What's your thoughts on the old "plexiglass sandwich" type of case?

author: Fsck
author_rank: Super Contributor
timestamp: October 03, 2013, 02:13:40 am
content: I find the plexiglass sandwich too vulnerable personally.I really like my cases to have solid sides all the way around

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 02:27:36 am
content: Quote from: george graves on October 03, 2013, 01:51:32 amThey were ok at first for some things (and still are), but now it seems everyone is doing it regardless of whether it's the best way or not.For something like the uCurrent I'd rather have an open top and side walls to grip.Like this very crude mockup attached.The paper mockup isn't accurate, you'd screw into the case holes instead of the PCB holes, so more like the real PCB pictured.This case is available from many sources, costs a dollar or so in volume, you can use both halves (halving your cost). No cutouts or machining required, no front panel silkscreen or label required, and you can change the battery (on top of PCB) without unscrewing the case. And can use either the gold binding posts as proposed in the GOLD version, or the right angle 4mm banana sockets as proposed by free_electronYeah, it's not pretty, but it's cheap and circuitry is adequately protected.There is a deeper version of the same size.In fact if the battery is put on the underside with the circuitry, then it's essentially the same as the old design, but has a shallower case, and plugs direct into the meter.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 02:56:13 am
content: Hmm... if those binding posts are moved down a bit, I could put an SMD CR2032 battery holder on the underside of the PCB on the top. No messy battery on the front panel, more room for big labels and name etc, and you can change the battery without unscrewing.

author: Fsck
author_rank: Super Contributor
timestamp: October 03, 2013, 03:09:59 am
content: The mockup is pretty clever, sort of the best of both worlds. I'm totally for it.

author: TMM
author_rank: Frequent Contributor
timestamp: October 03, 2013, 04:39:13 am
content: Good idea. I'd probably face the uCurrent the other way so if you have the meter propped up the uCurrent is facing up (PCB side up). It's not a big deal either way though since reversed polarity is not an issue for 99% of meters.

author: David_AVD
author_rank: Super Contributor
timestamp: October 03, 2013, 04:46:13 am
content: One thing I'm not fussed on are plug-in DMM adapters that stick up too far. The longer they are the easier they seem to break.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 05:07:39 am
content: Quote from: TMM on October 03, 2013, 04:39:13 amSome meters will need it one way, some the other way. So the polarity choice in the design is a bit arbitrary.

author: Lightages
author_rank: Unknown
timestamp: October 03, 2013, 05:23:50 am
content: Dave:If you do make the new uCurrent a direct plugin, then you need to account for meters that do not have a flat face. Have a look at the Brymens to see the concern. The middle two jacks are recessed a bit into the face because of the curved front.

author: pickle9000
author_rank: Super Contributor
timestamp: October 03, 2013, 05:27:35 am
content: Dave, would the jacks be staying at the top or would you move them closer to the meter to reduce mechanical stress?

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 05:29:02 am
content: Quote from: David_AVD on October 03, 2013, 04:46:13 amUnfortunately this case only comes in this length (90mm), and most that space is needed anyway if the battery goes on the back side.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 05:34:43 am
content: Quote from: Lightages on October 03, 2013, 05:23:50 amGood point.Just tried the BM869, and damn, they are recessed in a long way. My mock-up didn't fit as it was, I had to remove the case. But that would be the correct distance in production I think.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 05:36:00 am
content: Quote from: pickle9000 on October 03, 2013, 05:27:35 amGood point. No real reason they can't be close to the base.

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 05:40:30 am
content: I think I'll be implementing production testing into the panel as well this time, allowing 10 boards to tested at once. Should've done that way back, but was always "only a few hundred more"

author: pickle9000
author_rank: Super Contributor
timestamp: October 03, 2013, 06:03:33 am
content: Where you thinking of closing off the top of the case with a routed out bit of pcb?

author: EEVblog
author_rank: Unknown
timestamp: October 03, 2013, 06:10:32 am
content: Quote from: pickle9000 on October 03, 2013, 06:03:33 amNo, the top of the case would have the CR2032 battery access, perhaps sticking out a bit so you can grab it. Don't know, haven't looked at suitable SMD holders yet.

author: neggles
author_rank: Contributor
timestamp: October 03, 2013, 01:32:26 pm
content: Quote from: Lightages on October 03, 2013, 05:23:50 amQuote from: David_AVD on October 03, 2013, 04:46:13 amIt's relatively easy for an end-user to unsolder the banana plugs and solder on small (2-3") flying leads with banana connectors attached if their meter doesn't have the standard spacing or has recessed banana sockets.Perhaps this could even be offered as an option for a dollar or two more, as short male-male twin banana leads are available for under $1 in quantity (split in half, use one half for each unit) - or optionally just with no connectors included on the DMM end for an end user to add their own.

author: TMM
author_rank: Frequent Contributor
timestamp: October 03, 2013, 01:38:30 pm
content: Quote from: EEVblog on October 03, 2013, 05:07:39 amThat didn't even cross my mind heh. All my meters have the +ve on the right and gnd on the left. Even with the same meter it could be preferable to have it in different orientations when using the meter standing or lying down. If the range/power switch were on the edges it wouldn't matter which way it ended up but that could make the case difficult to implement. Another idea would be to have configurable input polarity with a switch or jumpers.Also, changing the aspect ratio so it is wider than it is long will reduce the ability of it to obscure the meter's display when lying flat on a desk and leverage on the plugs/jack.

author: Unknown
author_rank: Unknown
timestamp: October 03, 2013, 03:48:10 pm
content: I like the idea of a plug-in version (less bench space and messy wires), but I would be worried about mechanical integrity. The low Ohms adapter is much smaller, and I expect the Fluke thermocouple adapter to have its plugs mounted to the case, not just soldered to the PCB (I realize this is a mock-up). Is there anyway you can provide extra mechanical support for the male banana plugs?How common is it for DMMs to have a jack spacing other than 1.75"? I think this may be somewhat common in cheaper DMMs. So an easy way to convert it to female banana jacks would be nice.

author: TimNJ
author_rank: Super Contributor
timestamp: October 03, 2013, 04:12:13 pm
content: Quote from: alm on October 03, 2013, 03:48:10 pmYou could do a panel mount banana jack and then run a short low-R wire to the board.

author: Unknown
author_rank: Unknown
timestamp: October 03, 2013, 04:17:55 pm
content: That would be my solution, but it would increase assembly costs, and Dave has expressed a dislike for wired connectors in his discussion of the previous µCurrent design.

author: Dave
author_rank: Super Contributor
timestamp: October 03, 2013, 05:08:34 pm
content: Quote from: alm on October 03, 2013, 03:48:10 pmPretty much every multimeter I have ever encountered had the standard 0.75" (19.05mm) input jack spacing. I don't think you will find any decent meters on the market, that don't use the standard spacing. Maybe some shitty one-hung-low branded, but then again, if you do have a meter like that, you probably won't need a uCurrent adapter.

author: pickle9000
author_rank: Super Contributor
timestamp: October 03, 2013, 05:16:46 pm
content: Universal mounting,Assuming the board is wide enough you could just place the negative close to the center of the board the two positives on either side. Mount the plugs as usual but thus would allow the user to change them if reversed. As for jacks a hole large enough to mount a wire would be a good idea (or even a couple unpopulated jack mounts, that would look messy though, I hate messy).

author: AG6QR
author_rank: Frequent Contributor
timestamp: October 03, 2013, 10:00:46 pm
content: Quote from: Dave on October 03, 2013, 05:08:34 pmRight. And on the off-chance that you really do need to adapt it to a non-standard spacing, all that's required is a standard pair of stackable banana plug leads. All the ones I'm familiar with will accept male or female banana plugs or jacks. It might leave some connections with exposed uninsulated metal, but at the voltages involved, that ordinarily shouldn't be a safety risk.There's no need to do anything special to allow for non-standard spacing.

author: reagle
author_rank: Unknown
timestamp: October 06, 2013, 05:03:23 pm
content: I realize this is not a direct answer to the poll question, but my two annoyances with the existing uCurrent so far have been:Forgetting to turn it off and killing battery. An auto-off would be nice. And secondly, a limited frequency response. When dealing with all things wireless, you get a short "chirp", and then it jumps down to sleep/hibernation current. The shape of that chirp is usually not very accurately reproduced if I have a scope connected to the uCurrent. But since this is mostly a DMM accessory, maybe that's was not a design goal in the first place.Case-wise, making it less tall would be nice.

author: trevwhite
author_rank: Frequent Contributor
timestamp: October 08, 2013, 05:12:12 pm
content: It would be nice to measure processor current for various peripherals being turned on and off. For example turning on the ADC of a processor, making a measurement and then turning it off again could take literally 10uS. This unit would not be able to display this current change if connected to a scope would it?This kind of performance is more important than costTrev

author: AG6QR
author_rank: Frequent Contributor
timestamp: October 08, 2013, 05:39:43 pm
content: Quote from: trevwhite on October 08, 2013, 05:12:12 pmIn one of the first posts on this thread, Dave mentioned that the new version uses an improved amp with better performance to 30kHz. That's getting into the right order of magnitude to see 10uS, but perhaps not quite all the way there, especially not if you demand high precision.

author: trevwhite
author_rank: Frequent Contributor
timestamp: October 08, 2013, 05:41:38 pm
content: Maybe there is the option to upgrade the unit aftermarket with a better proposed op amp? Keep the initial cost down but provide an upgrade path for higher performance?

author: geo_leeman
author_rank: Regular Contributor
timestamp: October 08, 2013, 08:57:22 pm
content: Quote from: trevwhite on October 08, 2013, 05:41:38 pmThat seems like a lot of fuss for "minor" changes.I do like the plug in idea, but with a case to protect it. I often carry my gear to multiple labs in a bag and a free circuit board would not last. For me removing a couple of screws to replace the battery just isn't a big deal. I'd rather have a sturdy instrument with no shorting hazard.

author: george graves
author_rank: Super Contributor
timestamp: December 12, 2013, 10:38:55 am
content: Just a pet peeve of mine is the 5 different fonts types. The rule of thumb is only use two. Pick two, and that's all you get.I hope you've been shooting some video blog stuff as you've gone through the changes! Would love to see what you're dealing with! Would thumbs up!

author: EEVblog
author_rank: Unknown
timestamp: December 12, 2013, 11:05:30 am
content: Quote from: george graves on December 12, 2013, 10:38:55 amItisonly two fonts!Arial and Maiandra

author: EEVblog
author_rank: Unknown
timestamp: December 12, 2013, 11:07:15 am
content: Quote from: george graves on December 12, 2013, 10:38:55 amThere was essentially no choice. I needed DP3T that can handle at least 2A, and looks ta least half reasonable when exposed on the box.Yes, they are big (first time I've seen them in the real box), that's the price I had to pay.

author: george graves
author_rank: Super Contributor
timestamp: December 12, 2013, 11:27:36 am
content: Fair enough. Ship it!

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 08:17:28 am
content: Quote from: wilfred on December 12, 2013, 07:51:21 amThen don't buy it.Whilst I don't disagree they are a bit ugly, I can't help that, they are essential.QuoteIMO that would be uglier.QuoteSo drop a level in quality because you don't like the look it of the whole thing?No thanks.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 08:20:07 am
content: I'm currently setting up my Kickstarter campaign and am figuring out the options.Would anyone bother wanting an early low serial number unit hand assembled by me? (maybe 10 max) And if so how much extra would you pay?Any other "perks" ?

author: SeanB
author_rank: Super Contributor
timestamp: December 14, 2013, 08:53:51 am
content: What is the price? Low serial numbers up to 19 I would suggest an extra $50 for the hand assembly and test, along with a signed certificate from Dave as well. 20 to 50 $30 with a cert as well. Above 50 to 100 packed by Dave for $20 extra, but the cert is a copy with only the ser no hand written.That should be enough to cover the extra time, and if they come with Sagan prints in the tape from him helping you to pack that is free.

author: apelly
author_rank: Unknown
timestamp: December 14, 2013, 08:54:22 am
content: I wouldn't pay more for a low serial number. For an early unit I would. Maybe 20 bucks more.Don't forget levels including a blindingly expensive lunch, a tour of the towers, multi-packs for schools and hacker spaces, blog t-shirts, a two day workshop, gift for the poor, personalised blog entry, a mention on the website, an advert on the website, a custom pcb colour, a bare option and a cased option, a bare pcb, a kit, blog stickers, special forum section for community support, donate a dollar for eternal gratitude, first run and second run......just off the top of my head.Also, I'd rather buy one from you so kickstarter and amazon don't screw you out of 10%. I bet kickstarter don't allow that though.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 08:57:28 am
content: Quote from: SeanB on December 14, 2013, 08:53:51 amAbout $50 is the premium I was thinking for the first 10 units.I'm not sure if you can change the number after the Kickstarter campaign starts if this option proves popular?

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 09:02:12 am
content: Quote from: apelly on December 14, 2013, 08:54:22 amThe lower # units get shipped right away, I have the parts now, and get my thermal oven on Monday.QuoteIt does get kinda insane...QuoteThe Forum supporters will be able to buy one outside of "the system"

author: SeanB
author_rank: Super Contributor
timestamp: December 14, 2013, 09:26:06 am
content: Quote from: EEVblog on December 14, 2013, 08:57:28 amFirst come first served. Might be better to reserve the first 19 for the supporters and offer the remaining 80 on the KS page. Easy to explain that those are for the initial backers who got you off the ground. You might want to offer a cert for an extra $10 plus postage, for those who get one and want the DaveCAD cert and a signed page. That could be as simple as the circuit diagram, layout and your signature on the bottom. Simple addon at low cost and low effort on your side, as you already have the Tyvek envelopes to hand.

author: apelly
author_rank: Unknown
timestamp: December 14, 2013, 09:46:12 am
content: Quote from: EEVblog on December 14, 2013, 08:57:28 amI think not, but you can add more options. I've seen plenty added after a campaign is underway.On another note, don't forget to get your resellers to blog about it.On second thoughts, maybe that'd just do them out of sales. Then again; in the spirit of open source... maybe they would. Whatever. Can't hurt to ask.

author: Bored@Work
author_rank: Super Contributor
timestamp: December 14, 2013, 10:06:02 am
content: Quote from: EEVblog on December 14, 2013, 09:02:12 amReally? What do you have to lose?E.g. if you offer a combination of 10 uCs plus an advert, for the price of 10 uCs and your usual advertising rate? If someone buys it you have sold 10 uCs and an advert. If no one buys it you haven't lost anything. Same for a blog post mentioning, yet another kind of advertising sold. Or the $5000 lunch? If someone buys it you order a table at a nice restaurant, spend a few hours there and pocket the difference of $5000 and the restaurant bill. Not bad for half a day's work and a good lunch. And if no one buys it you lost nothing.Since the rulers went so well you could at least try autographed uCs. Effort: A white permanent paint pen, some time for signing the cases, some time for the separate shipment. If no one buys them you are only stuck with the cost of the pen.

author: Skimask
author_rank: Super Contributor
timestamp: December 14, 2013, 10:15:16 am
content: Count me in for at least one...if they make it to this hemisphere. Might have to swap the input and output jacks thoughIncidentally, I built up one of the "old" designs, using non-spec parts (closest resistors I could find in my bins, used a TL084, etc). It worked...-ish. Likely not accurate at all, but good enough for comparative 'A' vs 'B' readings for sure.

author: Bored@Work
author_rank: Super Contributor
timestamp: December 14, 2013, 10:22:05 am
content: Or another idea: A bundle with some Dave CAD pads.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 12:05:21 pm
content: Quote from: Bored@Work on December 14, 2013, 10:22:05 amNice, but probably too late for that.

author: peter.mitchell
author_rank: Super Contributor
timestamp: December 14, 2013, 12:41:05 pm
content: Quote from: EEVblog on December 12, 2013, 11:05:30 amActually I get that peeve too, I don't know what it is; maybe maiandra doesn't seem "serious" enough for this peice of equipment?Offer a $500+ GOLD GOLD edition, where you have no solder mask on the front, and a flood fill of hard-coat gold! (unsure if this is feasible) - that said, what is the front flood fill connected to?

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 01:27:07 pm
content: Quote from: peter.mitchell on December 14, 2013, 12:41:05 pmOutput common.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 01:43:33 pm
content: Quote from: Bored@Work on December 14, 2013, 10:06:02 amIt seems KS no longer allow multiple units on the same reward for tech projects.

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: December 14, 2013, 01:50:10 pm
content: Quote from: EEVblog on December 14, 2013, 08:17:28 am

author: jebcom
author_rank: Regular Contributor
timestamp: December 14, 2013, 04:23:05 pm
content: Quote from: EEVblog on December 14, 2013, 01:43:33 pmStick 10 of them together with bubble gum and offer a 10-position current measurement device.

author: calexanian
author_rank: Super Contributor
timestamp: December 14, 2013, 07:23:36 pm
content: Quote from: EEVblog on October 03, 2013, 12:22:42 amNew group project. DIY home injection molding unit!

author: Legit-Design
author_rank: Frequent Contributor
timestamp: December 14, 2013, 08:26:50 pm
content: I want one from B-stock, with greatly reduced price. If it has the bodgiest bodge made by Dave, would be even better!

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 09:20:44 pm
content: When it comes to the first unit, most KS's seem to offer a lower price for the early unit and first backers. That seems a bit arse-about to me, if you want early priority, pay more.I can understand enticing a low number of initial backers to get the project running though...Opinions?

author: robrenz
author_rank: Super Contributor
timestamp: December 14, 2013, 09:41:24 pm
content: I think in your case It is more of the "celebrity effect" (said with the utmost respect) that people would pay more for the autographed or hand assembled etc. as opposed to getting units sooner than others.

author: apelly
author_rank: Unknown
timestamp: December 14, 2013, 09:55:20 pm
content: Quote from: EEVblog on December 14, 2013, 09:20:44 pmYes, arse-about, but sometimes these early units are still in beta. Some campaigns do charge a bunch more for their early beta or hand assembled units too. And sometimes you get one from a production run included when it's ready.Charge more for the early ones. I'd suggest being quite clear that the price reflects the privilege, not the product though otherwise you might get pissed off users when they see sparkfun selling them for less. Also, you can still offer an early-bird thing for early backers that comes from a full production run and an early-delivery premium option.I'm sure you'll get enough backers anyway.Did you follow the HackRF project? Their kickstarter used some similar techniques.Also, I forgot to mention, if you have some rulers left you can bundle them as one of your rewards.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: December 14, 2013, 10:03:45 pm
content: CastAR model would most likely be the best. However you could offer few for a lower price, but they would be shipped much later, since they are already getting lower price. Why have lower price AND shipped earlier. Always makes me want to bang my head on a wall () when projects offer limited numbers of something really really cheap and then add something like micro USB cable or similarly stupid but for 10$ more, all those are for limited number of people.I'm sure you Dave will get enough initial backers even without tricks like that. I'm sure The New µCurrent will be success like µRuler Pozible was. You have the fan base to back it up. You have already been teasing with that for so long. Just make sure you do lots of marketing. Make many vblogs about it, not just one. Mention it in every vblog you do. Try to get other people to blog about it too. Do it like CastAR did, they had constant stream of new videos about their product. More publicity is better.And maybe a version without the case/giffy box? Just bare assembled board, most people can source similar boxes easily from local stores.Also please try to ship these from hong kong or singapore post or something really cheap and with tracking number. Ebay sellers from china and also now from Hong kong tend to ship their stuff from singapore post, it's just so much faster and all that. Also shipping from somewhere else than Australia must be so much cheaper. If the cost is down it must mean more people want it.Quote from:http://www.kickstarter.com/projects/technicalillusions/castar-the-most-versatile-ar-and-vr-system/?ref=kicktraq

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2013, 11:35:00 pm
content: Quote from: Legit-Design on December 14, 2013, 10:03:45 pmIt ain't that easy. You have to find a shipper you can trust to do the job properly, and that can automatically deliver the tracking numbers to the individual backers etc.

author: Kohanbash
author_rank: Regular Contributor
timestamp: December 14, 2013, 11:51:47 pm
content: I would rather pay a little bit more and get a "large" unit that I will not loose. I have lots of random dongles, I think the small version would get lost in the mess. I also do not like the idea of jumpers since they are easy to loose.Dave- If you were doing a teardown and saw jumpers for a setting that will often be changed and that could easily be lost, what would you say?edit: Just noticed that most of the design messages were from October...

author: lgbeno
author_rank: Frequent Contributor
timestamp: December 15, 2013, 04:02:17 am
content: Sorry I'm very late to the party. Have you considered flying leads off of the uCurrent? Sort of a hybrid between the old design and some of your new concepts.I do like the idea of 3 separate fixed range models as well if it makes things cheaper. Also gives you more options on how to structure the kickstarter and buying power with vendors.What about a Bnc output connector to attach to a scope or use the adaptor to attach to a dmm.I noticed CR123 batteries are getting more popular for LED flashlights these days.Anyway easy to make suggestions hard to make decisions... Good luck.

author: Six_Shooter
author_rank: Regular Contributor
timestamp: December 16, 2013, 12:46:13 am
content: Quote from: bookaboo on October 02, 2013, 08:05:44 amI agree about the mechanical stress. I've always looked at items that plug the component directly into the device they are to be attached to as "lower cost" and potentially and inferior product to something else on the market that does the same job, but uses even a short lead to connect to the host device. It is likely something that will break in my possession/use as well, not because I'm necessarily negligent of my tools, but I do use them, and usually use them in harsher environments, meaning extreme changes in temperature, falling off tables/surfaces/hanging apparatus, etc. If something like the plug in uCurrent is plugged into my meter directly, there's a good chance that it and possibly the DMM could get damaged, when, not if, this happens. That being said I haven't seen any other devices on the market like this, so there's nothing to compare against.I HATE jumpers, HATE them. The only time I tolerate them is when it's an initial install/set-up that will never need changing again, otherwise give me a switch. I hate jumpers so much, I actually made adapters to plug switches onto the jumper pins for the "robot" I had to make in class this past semester (Just a little two wheeled thing that we needed to build and program to drive on a rectangle). After turning the bot on and off twice, I dug out out some switches and female .1" header to make these adapters. I made the adapters because I didn't want to have to search for switches in the board layout software we were using, otherwise switches would have been mounted directly to the board. Have I mentioned how much I hate jumpers?Quote from: Legit-Design on December 14, 2013, 08:26:50 pmHAHA, this IS the Gold right here! I'd buy that.Quote from: lgbeno on December 15, 2013, 04:02:17 amAs I read some of the posts in this thread I thought the same thing about a flying lead set. The only problem I find with that is that the wires usually tend to break over time, so I don't think it solves anything here.I like the idea of small, but not at the cost of being robust, reliable, and easy to use. Give me big clunky switches, some solid posts/banana connections, something to hold on to, something that feels like I can use it without worrying about how gingerly I need to pick it up or set it down.I guess this is partly because of the time and area I was raised in, where something of quality had certain physical aspects to it.

author: tse
author_rank: Newbie
timestamp: December 16, 2013, 06:24:20 am
content: For me most important is, as an professional user, its possible to order though rs-components, farnell or conrad.Our payment system doesnt allow "strange" websites.

author: george graves
author_rank: Super Contributor
timestamp: December 16, 2013, 10:56:57 am
content: Adafruit is one of his distributors.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: December 19, 2013, 07:13:44 pm
content: Hi group,I am the process of building my own ucurrent. I have deviated a little from Dave's original design. Here is my version:I have moved my version to a new thread.https://www.eevblog.com/forum/projects/diy-ucurrent-design/msg350601/#msg350601I have answered Wilfred's question in the new thread.Jay_Diddy_B