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joric edited this page May 20, 2019 · 13 revisions

Mitosis PCB

Mitosis-PCB

Unused pins:

  • left pins: 11, 12, 20, 22, 25, LED pin 23
  • right pins: 11, 12, 16, 18, 20, LED pin 17

Pins that may be used for side autodetection:

  • left-only pins: 16 (L_S16), 18 (L_S22)
  • right-only pins: 22 (R_S22), 25 (R_S16)

Keyboard matrix

There is no matrix, all keys are wired directly to GPIO pins. There were speculations that Core 51822 has 32 GPIO pins available, so it's possible to make an Atreus62 clone without using a keyboard matrix. It is not true. GPIO 26/27 are shared by the 32kHz crystal and there are only 31 GPIOs hence PIN31 is not existing. So you could only have 29 keys on each side (58 total) if you manage to layout them without crossing.

Bill of Materials

  • ST-LINK/V2: $2.54, had in stock (you can also use $1.80 STM32 board instead).
  • YJ-14015: nrf51822 modules, 3 pcs: $10.5 ($3.50 * 3), free shipping, need 2/3, so $7.
  • 10 main PCB's from EasyEDA, $13.32 ($2 + $11.32 for trackable shipping), used 4/10, so $5.32.
  • 3 receiver PCB's from OshPark, $5.40, free shipping, used only 1/3, so $1.80.
  • Arduino Pro Micro from Aliexpress (price varies from $2.54 to $4), had in stock.
  • Si2302 mosfets: board survives reverse polarity for a while, you may just short the pads.
  • ASMB-MTB1-0A3A2 from Aliexpress (or Cree CLVBA-FKA, or 3 single LEDs, very optional)
  • AMS1117: 5v to 3v regulator, had in stock. You probably can use diodes for 2v drop.
  • 1206 4.7k resistor arrays, 2 pcs: had in stock (taken from an old motherboard).
  • Switches and caps: most of you have more than you can handle.

Total

  • Keyboard: $12.32 ($7 + $5.32) and I got enough PCBs to build 3 and they can reuse receiver.
  • Receiver: $7.84 ($3.50 + $1.80 + $2.54) firmware upgrade to ble and you wouldn't need it at all.

So, about $12 for the whole keyboard.

PCB Manufacturers

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