EEVblog #573 - Mailbag - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: January 27, 2014, 09:12:37 pm
content: Mailbag MondaySMD Adapter PCBs:https://github.com/maugsburgerNXP SMD Package Cheats:http://www.nxp.com/documents/other/Discretes_package_poster.pdfhttp://www.nxp.com/documents/other/Discrete_Flat_No-leads_DFN_package_poster.pdfHP 41 Calculator upgrade PCBhttp://systemyde.com/hp41/OHARARP Lab Notebooks:http://ohararp.com/CNC-Design in Finland Laser Cut 3D Signs:http://www.cnc-design.fiHacked Microsoft Lifecam DIYINHK USB Microscope:http://www.diyinhk.com/shop/usb-microscope-1080p-for-smt-soldering/48-1080p-smt-microscope.htmluARM 4-Axis Arduino Open Source Hardware Robotic Arm Kickstarter:https://www.kickstarter.com/projects/ufactory/uarm-put-a-miniature-industrial-robot-arm-on-your

author: Jorpy
author_rank: Contributor
timestamp: January 27, 2014, 10:00:48 pm
content: In case you want to "experience" your new game

author: Psi
author_rank: Super Contributor
timestamp: January 27, 2014, 10:49:54 pm
content: For the little TV you can make a small analog TV station with an old VCR.The VCR RF out (that normally goes to TV with VCR data on CH3 etc..) will transmit a very short distance if you put some wire on it to make an antenna.

author: EEVblog
author_rank: Unknown
timestamp: January 27, 2014, 11:11:11 pm
content: Quote from: Jorpy on January 27, 2014, 10:00:48 pmOh my FSM, the humanity!Epically bad!

author: Psi
author_rank: Super Contributor
timestamp: January 27, 2014, 11:19:59 pm
content: Must have been some other game that was tweaked a bit so they could call it BTTF and make money off the name

author: phil
author_rank: Regular Contributor
timestamp: January 27, 2014, 11:43:25 pm
content: Regarding the backlight for your new sign: Why not use the milk glass as diffusor? Mount some LEDs inside your lab to shine through the glass. Just do some math to find the optimal distance between glass and LEDs. Might even be a job for your makerbotAdd some form of case and a plug pack - done.Phil

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 27, 2014, 11:53:41 pm
content: Maybe re-purpose an LCD monitor backlight for the sign.If only you had the odd spare monitor or two.....

author: moemoe
author_rank: Regular Contributor
timestamp: January 27, 2014, 11:55:33 pm
content: Oops, I did just see the new video announcement on twitter, and yes, the letter was faster crossing half of the world than me uploading the designs of the adapters.Hopefully I won't forget to do this after a round of sleep, it's 00:47 here.As I wrote in the letter, some traces are too small, that's what happens when you throw together 10 designs in 4 hours. So I wanted to fix that known issue prior to publishing the design. I even forgot to remove some solder resist, the back of the sot223 was thought as universal 4 pin adapter, I already successfully used it for plcc4 leds.The manufacturer takes horrible sums for seperating or grooving boards, that's why I decided to cut them on my own.Good night

author: zakatov
author_rank: Newbie
timestamp: January 28, 2014, 01:02:19 am
content: Haha!Coming soon from China: it's the EAV Blog with Dave Johns!

author: PedroDaGr8
author_rank: Super Contributor
timestamp: January 28, 2014, 01:11:04 am
content: Quote from: zakatov on January 28, 2014, 01:02:19 am

author: 99tito99
author_rank: Regular Contributor
timestamp: January 28, 2014, 01:33:34 am
content: Quote from: mikeselectricstuff on January 27, 2014, 11:53:41 pmDitto: Had the same idea, Mike was quicker on the trigger.However, after that big clean-up ('The De- Hording') you may have thrown out all those monitors;Yea Right.Cheers,Mark**********************

author: iWalrus
author_rank: Newbie
timestamp: January 28, 2014, 02:08:20 am
content: Hi Dave,As any engineering student will tell you, it is drilled into your head (often ad nauseam) at all stages of education to always take notes, and to note down every single thing one is doing. I was inspired by that really nice Amp Hour notebook you were sent, to ask these questions:1. Do you take notes?2. What are the sorts of things you write down?3. How detailed are your notes?and4. What would you recommend an aspiring electronics engineer to bare in mind when taking notes?It may sound like a boring set of questions, but I really never got the hang of taking notes, and I'm sure my notes would not be the same even if i did the same experiment twice. So I ask: What would Dave do?I am new to the forum, but i watch all of your new videos religiously, even the boring bits. Maybe it could be the topic for a really back to basics video?Cheers, and keep the cameras rolling!- John (Auckland, NZ)

author: Excavatoree
author_rank: Frequent Contributor
timestamp: January 28, 2014, 02:21:42 am
content: Quote from: PedroDaGr8 on January 28, 2014, 01:11:04 amSome of my Japanese coworkers call me Mr. Johns.

author: EEVblog
author_rank: Unknown
timestamp: January 28, 2014, 02:36:00 am
content: Quote from: phil on January 27, 2014, 11:43:25 pmI've done some experiment through the frosted office glass and it's still the same, it's just not spectacular enough. I suspect even a nice even panel light on the back is going to look very ordinary.

author: electron_misfire
author_rank: Contributor
timestamp: January 28, 2014, 02:44:01 am
content: Quote from: EEVblog on January 28, 2014, 02:36:00 amI suspect simple wax paper (baking paper) will do the trick

author: ales22
author_rank: Contributor
timestamp: January 28, 2014, 03:11:03 am
content: Just quick idea, sorry if I'm totally wrong.Is there any chance to peel off the white plastic? Then you can place another layer under the white letters to stop the light. Something thin and reflexive should do the job, like aluminum foil. Then only the contours would be lit.iWalrus: At first get a decent pen! I screwed my hand and my writing with cheap rubbish ballpoint pens (fortunately it wasn't permanent). I can recommend rollers, definitely much better than ballpoints. You don't have to press too much and they have usually finer tips. But get some good brand like Pilot, Parker, Timbow... Cheap rollers skip often or scratch the paper. And of course, as the student, you will need some with high capacity cartridge :-)

author: codeboy2k
author_rank: Super Contributor
timestamp: January 28, 2014, 05:29:21 am
content: Wow!, totally awesome sign there Daveyes definitely ranks high.Now you've gone and made me want to watch "The Castle" again !! What a riot !

author: LapTop006
author_rank: Unknown
timestamp: January 28, 2014, 06:28:35 am
content: I was going to suggest an EL panel to light the sign as they're easy to cut down to size.

author: jwm
author_rank: Regular Contributor
timestamp: January 28, 2014, 08:14:29 am
content: Something I'd love to see you do with that sinclair TV tube is a fundamentals friday on high voltage circuits, driving the tube with a function generator to show Lissajous figures for instance and explaining the driver circuit. It would also be a good way to demonstrate how analog scopes work. Something about a true fully analog scope the size of one of those crappy DSO quad nano thingies also just appeals to me.

author: ion
author_rank: Regular Contributor
timestamp: January 28, 2014, 11:06:24 am
content: Try placing LEDs along the edge of the sign. That should give an even backlight.

author: moemoe
author_rank: Regular Contributor
timestamp: January 28, 2014, 11:13:52 am
content: I just finished the github upload of the breadboard adapter designs:https://github.com/maugsburger/smbb/blob/master/README.mdAnd because I got the question inside a youtube comment: I have still some left, so if anyone is interested in getting some, just contact me using the forum's messaging system.

author: arekm
author_rank: Unknown
timestamp: January 28, 2014, 02:46:59 pm
content: Quote from: Psi on January 27, 2014, 10:49:54 pmOr just RF modulator likehttp://www.amazon.com/BELKIN-F8V3063-Belkin-RF-Modulator/dp/B00076FVP6

author: plug
author_rank: Newbie
timestamp: January 28, 2014, 03:07:20 pm
content: You could try a CCFL or other tube style backlight, and the diffuser from a LCD monitor. That should give you good even lighting, and you could use colored plastic wrap to change the color.Love the blog, and keep up the good work.

author: iva
author_rank: Contributor
timestamp: January 28, 2014, 07:18:03 pm
content: Like the adapters but I wonder if all the fancy pads (see minute 5:40 on the video) in some of them might have too high parasitics for some applications?On the other side if you are using an adapter probably you're not going too high in frequency anyway...

author: moemoe
author_rank: Regular Contributor
timestamp: January 28, 2014, 10:43:39 pm
content: Quote from: iva on January 28, 2014, 07:18:03 pmThe breadboard itself also has some capacities:And if you think of the capacity as C=\varepsilon_0\varepsilon_r \cdot { {A} \over {d} }, with A something like 35µm x 3mm and d 2mm, it's nearly nothing.

author: lewis
author_rank: Frequent Contributor
timestamp: January 29, 2014, 12:52:19 am
content: Look at the size of that aerial. Add any value?

author: scientist
author_rank: Frequent Contributor
timestamp: January 29, 2014, 02:06:15 am
content: Dave: You know, moving the robotic arm's servos manually can damage the pots and strip the gears. Don't do that!

author: EEVblog
author_rank: Unknown
timestamp: January 29, 2014, 02:22:31 am
content: Quote from: scientist on January 29, 2014, 02:06:15 amErr, it happens all by itself under it's own weight...

author: free_electron
author_rank: Super Contributor
timestamp: January 29, 2014, 02:23:03 pm
content: That lab notebook is a beauty but it has a serious flaw : no sequentially numbered pages !This makes it unusable as a lab notebook.Why am i nitpicking ? Because the documentation trail requirements state that there has to be a mecha ism in place to verify no documentation was purposely removed. Tear out a page and it is obvious as the numbers dont match anymore.Lab notebook rules state that a page should never be removed. A mostake should never be made illegible. When you make a mistake simply draw a cross through it and mark it as wrong. It has to remain readable.The reasons are multiple: so someone can duplicate your work. So you can go back to something that didn't work then, but you have a solution for now. And most importantly : to claim ownership of original work if you ever apply for patents.Every page should have a headerbar where you write the date you started using that page , and its pre-printed sequence number.

author: nihilism
author_rank: Regular Contributor
timestamp: January 29, 2014, 03:08:55 pm
content: Quote from: arekm on January 28, 2014, 02:46:59 pmOr just fire up the old channel 7 transmitter.....

author: Stonent
author_rank: Super Contributor
timestamp: January 29, 2014, 03:26:06 pm
content: Quote from: EEVblog on January 27, 2014, 11:11:11 pmI remember renting those games from the video store...Odd that they didn't seem so bad when you're 10.And was it just me or does the guy in the video look like a young Ben Affleck?

author: AlfBaz
author_rank: Super Contributor
timestamp: January 29, 2014, 03:54:18 pm
content: I don't know how much you want to mess with that excellent sign, but if you were game you could mask it up and repaint the letters so they were opaque then from the back drill some blind holes into the raised letters and pop some funky RGB LED's in there allowing the light to come out of the sides of the letters

author: djlorenz
author_rank: Contributor
timestamp: January 29, 2014, 11:28:31 pm
content: oh my gosh what a nice baby robot arm... love it!kickstarter price it's quite high... i think i will wait for the stepper version.. i've a lot of stepper motors here form moving head lights... should be a nice project!

author: VK3DRB
author_rank: Super Contributor
timestamp: January 30, 2014, 11:01:23 am
content: The centre pin ground or +V on the DC connector? A good way of checking polarity of the DC connector pins is to check out the electrolytic capacitor printed polarities and associated tracks. An annoyance. All the PCB designer had to do was label the polarity.The designer of the analogue TV should have been put in the stocks and have tomatoes tossed at him for not having a pin 1 marker in his overlay or a square pin designating pin 1.A parallel is software developers who use ambiguous function names and variable names, or don't bother commenting their code because when it all comes down to it, they are really just dickheads disguised as programmers.

author: bronson
author_rank: Regular Contributor
timestamp: January 31, 2014, 09:47:05 am
content: Random question... Why do a lot of PCBs have hairline traces with acres of bare board around them? Resistance and inductance go down as the trace gets wider so, within reason, there's little downside to fattening them up a bit right? (yes, capacitance gets horrid if you have wide traces hugging ground planes or separated by hairline cracks so don't do that. Just make them a little wider.)I ask because a few years ago I soldered an Allegro motor controller to a breakout board that had the same narrow traces as the mailbag boards. One by one I started burning and jumpering traces until it was mostly wire. Irritating! And I think it was only moving a few hundred mA.Gotta be a reason people make those traces so thin yeah?

author: moemoe
author_rank: Regular Contributor
timestamp: January 31, 2014, 11:03:48 am
content: Quote from: bronson on January 31, 2014, 09:47:05 amIn my case, it was just the default minimum trace width I've overseen because I was in hurry filling up the blank space. In the current revision, this is already fixed.In case of your motor controller, I would say it was just horrible design or bad testing. I had the same issue with a rc helicopter light controller, where it could be fixed by soldering additional wires on.I'd say the only two cases for small traces are controlled impedance and space saving, at least as long you stay at low frequencies.

author: bronson
author_rank: Regular Contributor
timestamp: January 31, 2014, 08:33:50 pm
content: It very well could be the same reason on those other breakout boards. Just splat 'er down and ship it.

author: electrolux
author_rank: Regular Contributor
timestamp: February 04, 2014, 12:12:31 pm
content: Is there any website with the plans and programming code for the robotic arm? I hear it's open source.

author: electrolux
author_rank: Regular Contributor
timestamp: February 11, 2014, 10:41:18 am
content: Quote from: zakatov on January 28, 2014, 01:02:19 amWhat a way for a first post.

author: electrolux
author_rank: Regular Contributor
timestamp: February 11, 2014, 10:45:56 am
content: Quote from: EEVblog on January 29, 2014, 02:22:31 amI like that answer.

author: Bzzz
author_rank: Contributor
timestamp: July 20, 2015, 11:46:08 pm
content: A little late, I know...(watching the episodes in reverse)I found the NXP packaging cheat sheet quite handy, but obviously it just covers SMD parts. Is there also a THT sheet available? I know the standard TO-3/5/18/66 cans and the usual TO-92/126/220 transistor packages, but I always have to look up cans with a different number of pins (like TO-72), diode packages like DO-5/201, larger non-DIP ICs like TO-200, smaller (bigger) transistors like TO-237 (TO-247/264) and also wattage of resistors is up for guesses unless stated on the body. So a reference sheet for those would be nice, too...