Technical reference
openlabbench
Pinouts, part equivalents, printable cheat sheets.
- pinouts
- 73pinouts
- parts
- 47parts
- substitutions
- 204substitutions
Interactive pinouts
Hover a signal, every pin carrying it lights up. Click a pin for its aliases, peripheral mappings and the gotcha nobody writes down.
Substitutions, explained
An IRF540N is not an IRLZ44N. A BMP280 has no humidity channel. Every swap is graded, and says what changes.
Vector cheat sheets
One printable SVG per board, built from the same data. Sharp at any size, clean in black and white.
One color language, everywhere
One electrical role sets a pin's color. Bus capabilities stack on top, because a GPIO that is also SPI clock is both.
Start here
All pinouts →RPi 40-pin
3.3 VRaspberry Pi 40-pin GPIO Header
The J8 header shared by every 40-pin Raspberry Pi, from the Model B+ through the Pi 5. Names are BCM numbers, which is what libgpiod, pigpio and the Python GPIO libraries expect.
ESP32 DevKit
3.3 VESP32 DevKit V1 (30-pin)
The common 30-pin ESP32-WROOM-32 board. Plenty of GPIO, but four are input only, five are strapping pins and half the ADC stops working the moment WiFi comes up.
Blue Pill
3.3 VSTM32F103C8T6 Blue Pill
72 MHz Cortex-M3 with real SWD debugging for about the price of a Nano. Orientation below has the USB connector at the top.
Pico
3.3 VRaspberry Pi Pico (RP2040)
RP2040 board with 26 exposed GPIO, three ADC channels and the PIO blocks that make it unusually good at bit-banged protocols. Pin 1 is the top-left castellation with the USB connector facing up.
Uno R3
5 VArduino Uno R3
The ATmega328P reference board. 5 V logic throughout, which is exactly why it still gets used for anything driving relays, LED strips or older 5 V peripherals.
6502
5 VMOS 6502
The 8-bit CPU behind the Apple II, C64, NES and BBC Micro, and still the usual first homebrew computer build.
It is all plain JSON
A pinout is one file in data/boards/. Drop it in, and the page, the search index and the cheat sheet appear on the next build.
Read the schema