My 8×8 grid of exhaustion

So for the midterm, I decided to make a board that would control an 8×8 LED Matrix using a flex sensor.
The idea was to encase the sensor within an elastic band with a quick closing so that when the band was straight – nothing would be happening, and when it was around my wrist – there’d be an animation.

IMG_8222 from Shreiya Chowdhary on Vimeo.

What I knew – Hey! I have a few of these matrixes and a flex sensor somewhere. Let me just use the cool stuff I have!
What I know now – I’m an idiot.

Why I’m an idiot –

I planned the idea before the break. Had the main parts ready –


Thought I could skim through a few sample Eagle files and make mine + drill my board last Wednesday.
Thought every part I’d need would be in the shop.

Apart from the above plain simple stupidity I had brewing within me, I also felt that my idea was SO simple that I could do everything in a day.

It’s safe to say that I failed miserably.

1. Made my design with Andy’s help but didn’t save it so it vanished when Eagle closed unexpectedly while I was getting water. To drink.

2. Re-made my design to realise that everything was not going to be as simple as the marquee and I had too many holes that I had originally wished for.

This is my schematic

This is what I’m using finally

These are my failures

3. Okay, so my design is ready. But I know that there’s a chance that there’s going to be an issue with the milling because of the lines. And because I had so many holes. I had to decrease the width of the lines AND do top + bottom.
Also, I was very not good at milling. So, fun!

HH Midterm from Shreiya Chowdhary on Vimeo.

So it did happen. And that’s great. I owe its success to Amitabh. It really wouldn’t have been possible without him.

In fact, I feel everyone should hear the excitement in his voice when the milling looked fine.

WhatsApp Video 2018-03-25 at 12.54.15 PM from Shreiya Chowdhary on Vimeo.

4. Anyway, the board was ready. It looked pretty great!

14A627A2-3CB9-4C45-A541-BEC3953EFBF0 from Shreiya Chowdhary on Vimeo.

5. Now came a name chapter of distress – the ATmega, and programming it.

This took the entire day yesterday and ended up giving me a desk that looked like this.

Why the ATmega I was using was a strange, strange chip that refused to accept my friendship –

So after trying and failing MULTIPLE times

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Jesse helped me by pointing out that the ATmega was accepting a sketch only ONCE after burning the bootloader. If I uploaded a second one – it would just stop responding.

Eg: I would burn the bootloader – upload blink – then upload the LED Matrix sketch.

Why wouldn’t I upload the LED Matrix sketch directly? Because I’m an idiot. And Jesse pointed that out very politely.

6. Anyway, that’s done so now all we have to do is solder the board!

Oh also, when buying parts that are not available in the shop – it’s good to buy extras. I need two specific capacitors and I went to Tinkersphere and bought exactly two. Again, idiot.

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Oh, ALSO! I underestimated the size of the matrix while designing it because I thought all 8×8 matrixes would obviously be the same size. So the original matrix turned out to be larger than what was meant for it to sit on.
Again, Jesse saved the day by suggesting that I could make it sit in the air.

7. Losing my ATmega

Because there were multiple iterations, there were multiple ATmegas on the table.
And somewhere, I lost the one I had managed to program.
I know because we checked each one.

IMG_8296 from Shreiya Chowdhary on Vimeo.

IMG_8295 from Shreiya Chowdhary on Vimeo.

IMG_8294 from Shreiya Chowdhary on Vimeo.

There were more ATmegas tested. I just stopped taking videos.

8. Learning how to program an ATmega WITHOUT a breadboard.

This was the simplest thing I’d ever seen. Just program your uno and then take it out. Basically 5 hours of what I did in the afternoon crumpled into one 30 minute programming session.

Anyway, that is all. It doesn’t work. I will ask Andy why. But I think it looks pretty. And I hope that’s good for now.

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