2. soldering and wiring
- Fitment on the key switches should be perfect, the hole is 14x14x1.6mm and it should click in.
while not detrimental, to save you a headache in soldering, place the switches in with the pin orientation facing right (when looking from underneath, like in the right image above)
- Once you have them placed in, it should look like this:
- Now it's time for your keycaps, place them on and then it should look like this:
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We need to solder the grounds for each row of switches, it doesn't matter which pin you use for ground as switches don't have a polarity.
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These ground wires NEED to soldered pointing to the right (when viewing from underneath) to make sure they fit into the cut-out in the pico plate
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It should look like this:
Instead of stripping 3 small sections of my solid core wire, I just stripped the entire casing. You don't need to do it but it's easy this way.
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With the ground connections soldered, it's onto the signal wires.
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Soldering right to left (as viewed from the bottom) you should end up with an assembly that looks a little something like this:
I didn't take a picture without the pico plate installed, sorry :P
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With the all wires soldered to the pins of the switches, it's time to place the Pico plate into place with the void facing to the right (when viewed from the bottom) so it looks like the picture above.
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If you opted for the polyimide tape, then place some in where the Pico will be placed. You want to line up the the mounting stem in the top with the gap between Pin 2 and the ground pin of the pico for the best fitment. If you want to potentially take the Pico out in the future, use something more temporary but a couple dabs of CA glue will keep it in place. It should then look like this:
- Additionally, I used a small cut-off of strip board to make a ground rail. You could solder the bare wires directly to the Pico, a ground rail just makes it a little more convenient.
The pico plate is designed to fit very snuggly on the mounting stems, however it would benefit from a tiny amount of CA glue just to keep it secure, you can skip this bit, it is your choice.
- A wiring diagram can be seen here (where, when viewed from above, the switches are order 1-9):
graphic design is my passion B)
- Once those are soldered to the Pico it should look something like this:
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Now is when you should check the continuity between ground all of your signal connections to ensure you've not bridged anything and check that you haven't broken a solder joint on any of the switch pins.
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Before you go ahead and close it up, it's time for the firmware on the Pico.