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fabrication

Sunday night in the Advanced Circuits Lab

 
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What can you build with our Advanced Circuits Lab?  How about simple USB programmable electronics?   Morgan Redfield created this 3.3V basic trinket board on Upverter.  It's based off of the Adafruit Trinket It is 2 layers, with 5 wire vias.   It takes a little over 2 minutes on the Protolaser.  It's a pretty good start for any basic attiny85 project.

Basic Trinket - LV2 by motred 5d1d1e7d31a8d7a2 - Upverter

On one of our small panels, I can get 3 boards.  They look OK, but they don't really show off the laser.  

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It was a really slow Sunday what with Seahawks in the SuperBowl and all, so I thought I'd fork Morgan's design to give myself something to do.  Idle hands...

Octotrinket by mattw d63764ca4c58f0b5 - Upverter

I didn't have any real project in mind for this board, so I just picked fun features as I went along.

I decided I should make the board smaller, smaller is always better. Pad only USB A plugs are cool.  I also perforated it in case I wanted to get rid of it once it is programmed.

Adding a battery also seemed like a good idea.  We have 2032 snaps, and this gives it some versatility if I come up with a project that requires it on the next rev.

Through hole headers didn't make sense to me. This isn't going on a breadboard any time soon, so I just made pads go to the edge and turned off the holes in my CAM step.  Totally lazy, but it really is a one off, and I didn't feel like taking more than an hour to work on it.  

I really enjoy the zen of routing single sided boards, so I used a couple of 1206 zero ohm resistors and ran 6 mil traces. 

The battery on the back stopped me from dropping vias altogether, so I made them 1mm drills and avoided a toolchange on the PCB plotter.

PCB View of Octotrinket

PCB View of Octotrinket

Building the board went pretty fast.  a little under 2 minutes per board (both sides), and only 1 toolchange on the plotter.

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Assembly, because it's all SMT also went quickly.  Syringe on paste and place the components. A little bit of quiet time in the solder room.  It took an hour to paste and place all 4 boards on the panel.

After paste, I dropped the boards in the reflow oven on wave 2, and it was done in about 7 minutes.  I used paste and the Metcal pencil on the wire vias and the back snap.

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Assembled boards,  They need testing, but all in all not bad for 4 hours on a lazy Sunday.