I'm going to feel this in the morning

A project log for LED Oscilloscope Mk. II

Revamping a classic

Ted YapoTed Yapo 02/20/2017 at 03:3812 Comments

The 16x32 display boards arrived yesterday from OSH Park. I spent some quality time at the bench this evening.

The LEDs all work, although they got mounted with the wrong polarity - I got the first one wrong, and was very consistent after that. It will take a few inverters to make this work with the original circuit idea, but that's easier than re-working the board :-)

The really scary thought is that I have 2 more PCBs like this one.


zakqwy wrote 02/20/2017 at 16:39 point

Excellent music synchronization. I was going to post a joking comment about incorrect polarity... oof, not fun but good it'll be a fairly easy fix. Definitely worth watching in reverse, although somewhat less productive I suppose. 

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davedarko wrote 02/20/2017 at 12:48 point

at first it looks like you're putting them back :D hand soldering 110 LEDs was tough, this is madness :) It's also "good" to see that someone else can solder LEDs the wrong way. That's a 50-50 thing that happens to me more than I want :)

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Ted Yapo wrote 02/20/2017 at 17:43 point

Yeah, there were so many distractions with setting up the video, then considering where I'd stop for the day (I had intended to only mount some of them yesterday, then come back to it later), and all the rest.  The few seconds of thought I gave to which end should go where got me the wrong answer.  Maybe I should only make square arrays, where it doesn't matter :-)

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Lee Cook wrote 02/20/2017 at 12:43 point


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deʃhipu wrote 02/20/2017 at 08:45 point

How did you make sure they are oriented properly?

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Ted Yapo wrote 02/20/2017 at 17:38 point

There's a little green cathode mark on one end.  I can't see the mark clearly with the naked eye, but can tell that one end looks a little darker than the other - that's enough to tell the difference.  After placing them all, I checked with 10x magnification to make sure they were all good, then put them on the skillet.  Here they are close-up:

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deʃhipu wrote 02/20/2017 at 17:58 point

I see. The ones I have have the spot on the underside, which is not nearly as convenient.

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Ted Yapo wrote 02/20/2017 at 18:07 point

I wonder if there is a little jig that you could make (or print) to hold the tape they come on - it holds the black side down and lets you peel away the clear, advancing as you go - maybe with a little lever (or servo) to advance to the next LED.  If you could fit tweezers into the tape recess, it would make the whole process easier - they would always be oriented correctly - and right-side-up!

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deʃhipu wrote 02/20/2017 at 18:56 point

Make a LED extruder for your 3d printer :D

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Dr. Cockroach wrote 02/20/2017 at 08:40 point

That is a fantastic video, Do not think my eyes and hands could handle that :-)

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Morning.Star wrote 02/20/2017 at 08:20 point

Outstanding Lol, love the video... :-)

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esot.eric wrote 02/20/2017 at 06:21 point


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