Backplane

PCB Manager — Board Collection

A collection of custom PCB designs created in KiCAD, centered around the Raspberry Pi Pico (RP2040) platform. Each board is a standalone module that connects to the Main Board and extends its functionality via I2C, SPI, or UART.

Author: Piotr Kłyś
Tool: KiCAD 8.x
Firmware: MicroPython (Pico boards), AVR-GCC (ATmega boards)

Boards Overview

Board Details

Main_Board

The central development and integration board built around the Raspberry Pi Pico. Used to test all peripheral modules in the collection.

Features:

• RGB LED (PWM)
• 2× status LEDs (PWM)
• Buzzer (PWM)
• 2× push buttons
• ADC input with 100 kΩ / 200 kΩ voltage divider
• Connectors for all expansion boards (I2C, SPI, CAN, EEPROM, GPIO, INA, RTC, Relay)
• Optional multi-threaded test runner (_thread)

Firmware: Main_Board/Code/main.py

CAN_Board

CAN bus communication module using the MCP2515 controller over SPI.

Features:

• SPI interface to Pico
• Standard CAN 2.0 frame support
• Loopback, sniffer, and master/slave test scripts

Firmware: CAN_Board/Code/

• can_mcp2515.py — low-level MCP2515 driver
• can_communication.py — higher-level protocol
• hello.py, loopback.py, sniffer.py, can_slave.py, can_test.py — examples

EEPROM_Board

Non-volatile storage expansion using the M24C32 (32 Kbit / 4 KB) I2C EEPROM.

Firmware: EEPROM_Board/Code/eeprom_m24c32.py

GPIO_Board

16-bit I2C GPIO expander using the MCP23017, providing two 8-bit ports (Port A / Port B) with interrupt support.

Firmware: GPIO_Board/Code/expander_mpc23017.py

INA_Board

High-side power monitoring using the INA226 — measures bus voltage, shunt voltage, current, and power via I2C.

Default configuration:

• Shunt resistor: 100 mΩ
• Max current: 3.2 A
• Alert pin supported

Firmware: INA_Board/Code/measurement_ina226.py

RTC_Board

Real-time clock module using the PCF8563T via I2C. Provides timekeeping, alarm, and 1 Hz clock output.

Features:

• Date / time read and write
• Alarm support
• 1 Hz CLKOUT output
• Battery backup pin

Firmware: RTC_Board/Code/rtc_pcf8563.py

Relay_Board

2-channel relay board controlled via GPIO from the Pico.

Modbus_Board

RS-485 transceiver board enabling Modbus RTU communication over UART.

Power_Board

DC power supply module — voltage regulation and distribution for the board ecosystem.

MOSFET_Board

MOSFET-based switching board for controlling higher-power loads from Pico GPIO.

Amplifier_Board

Analog signal amplifier module.

ATMega_Board

Through-hole ATmega development board — classic DIP package, ISP programming header.

ATMegaSMD_Board

SMD variant of the ATmega development board — compact form factor.

Tree_Board

AVR-based LED Christmas tree — decorative board with animated LED patterns.

Firmware: Tree_Board/TreeCode/main.c (AVR-GCC)
Gerbers / renders: Tree_Board/PROD/

IoT_Logger_B

IoT data logger — revision B.

IoT_Logger_C

IoT data logger — revision C. Improved layout over revision B.

Pico_TH_Logger_SMD_PCF8563T_2.1

Compact SMD temperature and humidity logger based on Raspberry Pi Pico with a PCF8563T RTC for timestamped logging.

Pico_TH_Logger_Relay_SMD_PCF8563T_2.1

Extended version of the TH Logger adding a relay output for threshold-based control (e.g. ventilation, heating).

Repository Structure

pcb-docs/
├── <BoardName>/
│   ├── <BoardName>.kicad_pro      # KiCAD project
│   ├── <BoardName>.kicad_sch      # Schematic
│   ├── <BoardName>.kicad_pcb      # PCB layout
│   ├── Code/                      # MicroPython / C firmware
│   └── PROD/                      # Gerbers, renders, BOM exports
├── Boards_BOM.ods                 # Combined Bill of Materials
└── README.md

Each board may contain multiple revision subdirectories (e.g. 1.0/, 1.1/).

Getting Started

Requirements

• KiCAD 8.x — to open schematics and PCB layouts
• Thonny or mpremote — to flash MicroPython firmware to Pico
• AVR-GCC + avrdude — for Tree_Board / ATmega boards

Running firmware on Pico

1. Flash MicroPython to your Raspberry Pi Pico.
2. Copy the relevant driver file(s) from <BoardName>/Code/ to the Pico filesystem.
3. Run or import the module from the REPL or main.py.

# Example — INA226 power monitor
from machine import I2C, Pin
from measurement_ina226 import MEASUREMENT_INA226

i2c = I2C(0, sda=Pin(4), scl=Pin(5))
ina = MEASUREMENT_INA226(i2c, r_shunt_ohm=0.1, max_current=3.2)
print(ina.read_voltage(), ina.read_current(), ina.read_power())

Bill of Materials

A combined BOM for all boards is available in Boards_BOM.ods (OpenDocument Spreadsheet).

License

This project is licensed under the CERN Open Hardware Licence v2 - Permissive (CERN-OHL-P).

You are free to use, modify, and manufacture these designs. Attribution appreciated.