Author Topic: EEVblog #573 - Mailbag  (Read 18299 times)

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Offline lewis

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Re: EEVblog #573 - Mailbag
« Reply #25 on: January 29, 2014, 12:52:19 am »
Look at the size of that aerial. Add any value?
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Offline scientist

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Re: EEVblog #573 - Mailbag
« Reply #26 on: January 29, 2014, 02:06:15 am »
Dave: You know, moving the robotic arm's servos manually can damage the pots and strip the gears. Don't do that!
 

Online EEVblog

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Re: EEVblog #573 - Mailbag
« Reply #27 on: January 29, 2014, 02:22:31 am »
Dave: You know, moving the robotic arm's servos manually can damage the pots and strip the gears. Don't do that!

Err, it happens all by itself under it's own weight...
 

Offline free_electron

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Re: EEVblog #573 - Mailbag
« Reply #28 on: January 29, 2014, 02:23:03 pm »
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.

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Any comments, or points of view expressed, are my own and not endorsed , induced or compensated by my employer(s).
 

Offline nihilism

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Re: EEVblog #573 - Mailbag
« Reply #29 on: January 29, 2014, 03:08:55 pm »
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.

Or just RF modulator like
http://www.amazon.com/BELKIN-F8V3063-Belkin-RF-Modulator/dp/B00076FVP6

Or just fire up the old channel 7 transmitter.....
 

Offline Stonent

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Re: EEVblog #573 - Mailbag
« Reply #30 on: January 29, 2014, 03:26:06 pm »
In case you want to "experience" your new game ;)

Oh my FSM, the humanity!
Epically bad!

I 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?
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Online AlfBaz

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Re: EEVblog #573 - Mailbag
« Reply #31 on: January 29, 2014, 03:54:18 pm »
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
 

Offline djlorenz

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Re: EEVblog #573 - Mailbag
« Reply #32 on: January 29, 2014, 11:28:31 pm »
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!
 

Offline VK3DRB

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Re: EEVblog #573 - Mailbag
« Reply #33 on: January 30, 2014, 11:01:23 am »
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.


 

Offline bronson

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Re: EEVblog #573 - Mailbag
« Reply #34 on: January 31, 2014, 09:47:05 am »
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?
 

Offline moemoe

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Re: EEVblog #573 - Mailbag
« Reply #35 on: January 31, 2014, 11:03:48 am »
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?

In 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.
https://github.com/maugsburger/
Breadboard Adapters featured in EEVBlog #573 on Tindie
 

Offline bronson

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Re: EEVblog #573 - Mailbag
« Reply #36 on: January 31, 2014, 08:33:50 pm »
It very well could be the same reason on those other breakout boards.  Just splat 'er down and ship it.  :)
 

Offline electrolux

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Re: EEVblog #573 - Mailbag
« Reply #37 on: February 04, 2014, 12:12:31 pm »
Is there any website with the plans and programming code for the robotic arm? I hear it's open source.
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Offline electrolux

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Re: EEVblog #573 - Mailbag
« Reply #38 on: February 11, 2014, 10:41:18 am »
Haha!

Coming soon from China: it's the EAV Blog with Dave Johns!
What a way for a first post.
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Offline electrolux

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Re: EEVblog #573 - Mailbag
« Reply #39 on: February 11, 2014, 10:45:56 am »
Dave: You know, moving the robotic arm's servos manually can damage the pots and strip the gears. Don't do that!

Err, it happens all by itself under it's own weight...
I like that answer.
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Offline Bzzz

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Re: EEVblog #573 - Mailbag
« Reply #40 on: July 20, 2015, 11:46:08 pm »
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...
 


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