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Topic: PAW20 - LEDger Led (polarity) tester (Read 8771 times) previous topic - next topic

PAW20 - LEDger Led (polarity) tester

This weeks PAW is something that I have wanted to have for a long time but never gotten around making - until now that is :-)

Everytime I solder a SMD LED on a pcb I have to turn on one of my multimeters and flip it over to diode-test mode and then probe the SMD LED to see which connector is the anode and which is the cathode.  The LEDger is a small PCB with a button cell battery and smd footprints that allows me to, while still holding the LED in my tweezers. just hold it onto one of the footprints and see if it lights up or not.

While I was at it I added some other footprints both for SMD and thru-hole LEDs to make the board a bit more universal.  The PLCC6 footprint might save me some trouble testing a roll of RGB leds that I bought from eBay where about 30% was BBB instead of RGB :-(

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Re: PAW20 - LEDger Led (polarity) tester

Reply #1
I like those LED testers. Pretty convenient for SMD LEDs. And, you must be reading a Swedish novel while making this. :)

Re: PAW20 - LEDger Led (polarity) tester

Reply #2
I'll asked Ian for a giveaway for a few of these. So you'll have your chance of getting one for free. If you're not in luck you can soon get one from my Tindie shop https://www.tindie.com/stores/matseng/  :-)

Well, almost.  I just grabbed a book from a bookshelf nearby and it happened to be a Swedish book from the late 60'ies (or possibly the early 70'ies) about typography.

Re: PAW20 - LEDger Led (polarity) tester

Reply #3
[quote author="matseng"]I'll asked Ian for a giveaway for a few of these. So you'll have your chance of getting one for free. If you're not in luck you can soon get one from my Tindie shop https://www.tindie.com/stores/matseng/  :-)

Well, almost.  I just grabbed a book from a bookshelf nearby and it happened to be a Swedish book from the late 60'ies (or possibly the early 70'ies) about typography.[/quote]

Thanks man. It's cool. :)

Btw, I happened to have old Rosetta Stone "Learn Danish" material. Didn't quite finished book 1 - it's terribly hard. Scandinavian languages are pretty difficult to learn and to master. :)

Re: PAW20 - LEDger Led (polarity) tester

Reply #4
Does the coincell provide enough juice for blue LEDs? A nice lasercut sheet with cutouts for the LED would help positioning the LEDs. We had a simular idea for the partninja, but never tried it for real.

Nice idea, I really like it (i recognize 'your' problem :) )

Re: PAW20 - LEDger Led (polarity) tester

Reply #5
[quote author="Sjaak"]Does the coincell provide enough juice for blue LEDs?[/quote]
Hmm...  Good question....  Think so at least.  The Vf for the leds are not that sharp so even at a lower voltage than the Vf spec'd for 20mA there will be a lower current through it and at least a dim light output.  I'll test it when I come back home tonight.

The placement is not that problematic, it's worse to get proper contact. It helps a lot to put some solder on the pads and then wick it away leaving just a thin but slightly rough surface.  Doing that I can get a decent connection even on the 6-pin PLCC-6'es.

Re: PAW20 - LEDger Led (polarity) tester

Reply #6
[quote="matsengThe placement is not that problematic, it's worse to get proper contact. It helps a lot to put some solder on the pads and then wick it away leaving just a thin but slightly rough surface.  Doing that I can get a decent connection even on the 6-pin PLCC-6'es.[/quote]

you also can solder it and sand it down a bit. I always fighting solderwick :)

Re: PAW20 - LEDger Led (polarity) tester

Reply #7
Nice idea Mats, I also came across that problem (again) the other week when putting together the BP.

Re: PAW20 - LEDger Led (polarity) tester

Reply #8
I really like the arrangement of the resistors. They are like centipedes or ants walking to the power.

Re: PAW20 - LEDger Led (polarity) tester

Reply #9
Thanks :)

I like doing the boards reasonably symmetrical and "pretty" as long as it doesn't affect signal integrity or cause unnecessary routing.

I usually end up rearranging the connections to the ports on the microcontroller to ease routing the boards.  Then I'll just adapt for the weird order of bits vs pins in the firmware.  But sometimes timing constraints prohibits me from doing that, then the hardware routing have to suffer instead :)

Re: PAW20 - LEDger Led (polarity) tester

Reply #10
Found this nice little gem from over a year ago - still a neat project.
Doesn't seem to be any PCBs on Tindie though (?).
Are the files available for download anywhere? Or more Tindie PCBs coming?