Adafruit has released the QT Py BFF board, which provides CAN bus connectivity for compact microcontroller development boards thanks to Microchip's MCP25625 chip and transceiver.
The CAN bus is a small networking standard originally developed for cars and buses, used in many robotics and sensor networks that need more range and addressing than I2C and don't have the pins or computational power to handle Ethernet. CAN is a two-wire differential network, which means it is suitable for long distances and noisy environments.
Messages are transmitted at about 1 Mbps - you set the frequency for the bus, and then all "joiners" must match it and have an address before the packet so that each node can listen for messages intended just for it. New nodes can be easily connected because they just need to connect to two data lines anywhere on the shared network. Each CAN device sends messages whenever it wants, and thanks to clever data coding, it can detect message collisions and retransmit later.
The Adafruit CAN Bus BFF board is available from the company store for $8.95.
Messages are transmitted at about 1 Mbps - you set the frequency for the bus, and then all "joiners" must match it and have an address before the packet so that each node can listen for messages intended just for it. New nodes can be easily connected because they just need to connect to two data lines anywhere on the shared network. Each CAN device sends messages whenever it wants, and thanks to clever data coding, it can detect message collisions and retransmit later.
The Adafruit CAN Bus BFF board is available from the company store for $8.95.