Carbon by Seeed and 96Boards is an STM32F401 based BLE development board. It's perhaps a little over-specified to use just to control relays, but if you have an unused one lying around its a great alternative to STM32F103 boards.
- Install the Arm Embedded Toolchain (or similar arm-none-eabi- compiler), openocd and dfu-util.
- Clone this repo:
git clone https://github.com/daniel-thompson/usb-relay.git - Fetch the libraries:
cd usb-relay; git submodule update --init --recursive - Build the firmware:
make - Connect via the OTG USB socket for programming (you may need to be
root for this):
make -C src/stm32f4-relay-96bcarbon flash
Connections requires are:
- Connect via the UART USB socket and set the baud rate to 38400.
- USB5V (pin 11) and GND (pin 9) to relay board
- The relays should be connected using the pins allocated to LS-UART0 and LS-SPI0. This results in a 1:1 mapping between pin numbers and relay numbers; relay1 is pin 1 of the LS connector, relay 8 is pin 8 of the LS connector.
Note: The Carbon port uses the onboard FDTI USB -> serial bridge rather than emulating a CDC-ACM device. On Linux it will be presented as /dev/ttyUSBx.
> help
Available commands:
echo
help
led
relay1
relay2
relay3
relay4
relay5
relay6
relay7
relay8
uptime
> led on
> led off
> relay1 help
Usage: relay1 on|off|toggle|pulse
> relay1 toggle