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PCB WEEK 3

PAST BOARDS REWORK

With some help from the expertise of David it turns out that my board from last week DOES work, there was just two little bits of copper in one of the traces that was messing with the resistance between power and ground, after getting rid of that now my board works as intended! This left me with one other board I had to remake, that being the shark shaped one from week 4.

I bumped the resistor and LED pad size up to 1206 as I had already set to 0603, which we did not have resistors in that size. I also made the traces a bit shorter.

Another problem with my first attempt at this board was that the carvera seemed to inverse the pads, which happened again this time. I made the traces thinner and on my second attempt it cut the traces as intended, but in certain places it didn't engrave deep enough on half the board. Also the tail broke off but that wasn't a big deal compared to the issue the traces had.

Out of the four LED traces on the board, I managed to get one (the furthest to the right) properly carved out with no shorts, though it still was pretty rough. I only soldered here with the solder paste, which I had to had pump because the air tube was broken.

The solder paste went fine but I had some issues soldering the header, I'm not sure if it was just because I had low morale at this point or if I was haunted by a bad luck spirit on Monday but god was it a pain. It didn't short but the connection was very iffy at best so it was probably cold jointed. When I put it on the Metro board and ran code to have the LED on, the LED turned on for a moment but then stopped working. It was too short to get a picture of it on unfortunately.

SCHEMATIC WITH NEW PART

I browsed Digikey for a suitable part to use. I found this IRA sensor (HC-SR501). It senses any change in infrared that would indicate motion and returns a signal. This chip has a built in amplifier so this way it doesn't require a custom conditioning circuit which would be difficult to design. There was no working footprint for the HC-SR501 so instead I just put a 3 pin header that matches the male pins on the chip, the three being power, output, and ground.

I used the Arduino Uno R3 footprint since that is basically the same design the Adafruit Metro 328 has, which I am familiar with.

3D-PRINTED BOARD CASE

I decided to attempt to do this bonus assignment because I like the shape of my first board design and thought a case would compliment it well. I made a snap fit case with an opening on the bottom to allow the through hole headers to be inserted into the metro board. I also included several holes on top to line up with the LEDs on the board so they could be visible.

I designed it and started printing while cutting the board it's for so now I have this case for a non working board. At least the case works though