Assembly
The Polpad is an 18-key macropad with a display, built around an ESP32-C3 SuperMini. The module and the display sit in the top-left corner of the board, where the first two keys would be.
Parts
| Part | Quantity |
|---|---|
| ESP32-C3 SuperMini module | 1 |
| Mechanical switches (Kailh hot-swap sockets) | 18 |
| Diodes (one per key) | 18 |
| SSD1306 0.96” 128×64 I2C OLED display | 1 |
| Polpad board (PCB) | 1 |
| 3D-printed case (top and bottom) | 1 |
The board files and the schematic will be published soon.
Pinout
The keys form a 4-row by 5-column matrix, with 18 of the 20 positions used.
| GPIO0 | GPIO1 | GPIO2 | GPIO3 | GPIO4 | |
|---|---|---|---|---|---|
| GPIO10 | — | — | SW10 | SW11 | SW18 |
| GPIO7 | SW1 | SW4 | SW9 | SW12 | SW17 |
| GPIO6 | SW2 | SW5 | SW8 | SW13 | SW16 |
| GPIO5 | SW3 | SW6 | SW7 | SW14 | SW15 |
- Rows: GPIO 10, 7, 6 and 5, top to bottom, on the diode side.
- Columns: GPIO 0, 1, 2, 3 and 4, left to right, on the socket side.
- Diodes: cathode towards the row (COL2ROW).
- Display: I2C with SDA on GPIO8 and SCL on GPIO9, powered from 3V3, address 0x3C.
- Free: GPIO 20 and 21.
Printing the case
The case has two parts: the top, with the key frame and the display window, and the bottom.
- STL: slice
case_top.stlandcase_bottom.stlfor your printer. - Ready-made G-code: there is one for the Creality Ender-3 V3 SE (Cura 5.12, 0.12 mm layers). It only works on that printer.
The files are on the Download page.