Parts list
Everything that goes into one box. Any maker of these common modules will do, as long as the details in the right-hand column match.
The core
| Qty | Part | Details |
|---|---|---|
| 1 | Raspberry Pi Zero W | The original Zero W (not the Zero 2 W: the firmware is built for the original). Fit a 40-pin header, or solder wires straight to the holes. |
| 1 | microSD card | 2 GB or larger. |
| 1 | OLED display module | SSD1306 controller, 128 x 32 pixels, I2C, address 0x3c: buy a 0x3c module, as the setup page has no setting for another address. Not a 128 x 64 or SPI module. |
| 1 | I/O expander board | MCP23017, I2C, at address 0x27. The reference build uses the Waveshare MCP23017 board: leave its A0/A1/A2 address straps open for 0x27 (on that board, closing all three gives 0x20). With any other MCP23017 board or a bare chip, set and check the address yourself. With a wrong address the lamps stay dark. |
| 8 | LEDs | 5 mm, in any colours you like. |
| 8 | Resistors | 470 ohm, 1/4 W, one for each LED. |
| 1 | Audio amplifier board | MAX98357A, I2S input. Check its default gain and channel settings (see wiring). |
| 1 | Speaker | 8 ohm, 3 W, small enough for your case. |
| 1 | Speaker lead | JST-PH2.0 lead or adapter to connect the speaker to the amplifier's terminals, if your speaker has a JST-PH2.0 plug. |
| 1 | Power supply | Regulated, protected 5 V, centre positive, 5.5 / 2.1 mm plug. The prototype uses a 2.5 A adapter; no current rating for the whole box has been worked out yet. |
| 1 | Power socket | 5.5 / 2.1 mm DC barrel socket for panel mounting. |
| 1 | DA15 socket | Female, 15 pins in two rows (8 + 7), panel mount, solder cups. Not a VGA (HD15, three rows) socket. |
| 1 | DA15 plug and hood | Male, solder cups, for the PC end of the cable. |
| 1 | USB cable | A USB-A cable to cut up for the PC cable: you use its two data wires and ground, never its +5 V wire. |
| 1 | Case | See the case. |
| 1 | Inline fuse (optional) | A fuse holder and fuse for the 5 V lead from the barrel socket. Not in the reference build, but a good extra. |
| - | Hookup wire | Thin stranded wire in several colours, heat-shrink tubing. |
For the serial port (being tested)
Only if you want to add the RS-232 port now. The USB connection works without it.
| Qty | Part | Details |
|---|---|---|
| 3 | RS-232 converter boards | MAX3232, running from 3.3 V, with the T1IN, T2IN, R1OUT, R2OUT and RS-232 side pins brought out. The wiring plan was drawn for the SparkFun BOB-11189. |
| 5 | Resistors | 10 kilo-ohm, as pull-ups. |
| 1 | DE9 socket | Female, for the serial branch of the PC cable (DA15 pins 1-9 go to the same DE9 pins). |
| 1 | Serial cable | DE9, straight-through with all nine wires (not a null-modem cable), from that branch to the PC. |
Tools
- A soldering iron and solder.
- Wire strippers and side cutters.
- A multimeter, to check continuity and the 3.3 V and 5 V rails before the first power-up.
- A computer with a microSD card reader, to flash the firmware.
- A phone or laptop with Wi-Fi, for the setup page.
Next: wiring.