Homemade Hardware Week 7: Surface Mount and Acid Etching

First thing first: Fuck Surface mounting. Fuck it. It’s cool looking but like not worth my limited patience.

So I swapped my my surface pieces for through holes.

Acid etching on the hand… I actually enjoy and find less nerve wracking than milling. So I etched my board—Or rather 4 of them in case of one not working.  So I went with the motions, estimated the site of the print, printed it on the vinyl. So this was successful process:

  • Laminated it five times horizontally
  • Laminated it vertically five times
  • Put under iron for about 3-3 and half minutes,
  • Laminate horizontally two more times
  • Laminate vertically two more times.
  • Drop in water

And it was nice day today, and luckily Chino was on the floor. So instead of just waiting I decided to move on with the etching. It was nice slowly melted away the copper in natural light from a very sunny early afternoon in the shop. Followed the guidelines and disposed everything properly.

Then I separated them on the band saw. I made myself a little jig to keep it as straight as possible due to its small size and my paranoia working with  the saws, and I just eased it with scrap as a pusher. Trimmed  it on the guillotine and filed it down no entirely perfect but close enough.  Once that was done I drilled the holes out with the drill press in the PCB lab and washed off the toner with acetone. The pads for the capacitors kind of fused, but nothing a little scraping can’t fix. Beep tested and working just fine.

And then I was like, why not go further? Everything was there…so I put together one of the boards.

First issue being, they have the batter pack like two pins in Eagle but that wasn’t the case. I had to drill a few more holes to fit the little power piece—which separated the circuit. Patched with a bit of wire, beep test clear, and ready to go.

Got nothing when I had the 3v coin cell, which was odd, so I got a power source and put 3v on it. The light went on but there was no music. One thing to note was that ATTiny got super-hot so I stopped it. I am hoping it didn’t fry. (Someone suggested I go 5v, and I know that’s about the voltage we get through the Arduino through the ISB but if it got hot a 3v, I am not risking it at 5v.

It could be possible a matter of mixed pins? I think I need to fix either the code or the Eagle schematic somehow. This is showing an ATTiny as if it were surface mounted I think, it should be mirrored?

I might make a second schematic and try it, but as of this writing, it is a mystery.

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