openCAN

OpenCAN

A CAN bus board built to be hacked.

OpenCAN is an open firmware platform for working with vehicle CAN bus networks. The board sits inline on the bus as a man-in-the-middle device, reading, filtering, and rewriting messages in real time. Built on the SAMD21, programmable through the Arduino IDE, with fully open source firmware.

Stock Firmware: ArduAudi Mode

OpenCAN's stock firmware includes a ready-to-run ArduAudi configuration for Audi 2.7t B6/B7 swaps. No programming, no setup, just connect it to the bus.

In this mode, OpenCAN reads coolant temperature and A/C status directly off the CAN bus and drives the OEM radiator and auxiliary fans the way Audi intended, using the pwm outputs to switch the stock fan controller. It also adapts cruise control for the 2.7t without touching the factory stalk. Set, accelerate, retard, cancel, and resume all work as designed.

OpenCAN does the same job on a board that's also a full dual-CAN development platform. Wire it in, and it runs ArduAudi out of the box. Need something more later, reflash it and build whatever you need on the same hardware.

What it's for

Most CAN bus tools are either closed, expensive, or built for diagnostics, not control. OpenCAN is built for people who want to change how their vehicle behaves. Reassign a gauge. Translate a signal from one bus to another. Trigger a relay based on live sensor data. If it's a CAN message, OpenCAN can see it and act on it.

What's on the board

Two independent CAN bus interfaces (dual MCP2515 controllers), so you can bridge or translate between two separate networks at once. Eight digital outputs, six low-amp channels for switching loads directly, two relay-rated channels for higher current draws. Six analog inputs covering resistor-based sensors, switch-to-ground inputs, and 5V sensor signals.

Built on a familiar toolchain

OpenCAN runs on the Arduino core. If you've written Arduino sketches before, you already know how to program this board. No proprietary IDE, no licensing fees, no black box on the firmware side.

Open source firmware

Firmware source and board definitions are on GitHub. Fork the firmware, build your own application on the same hardware, extend it however you need. The bootloader ships on every unit, so recovery and re-flashing work out of the box.