If you are looking to connect to a vehicle’s CAN bus, then the newly launched open-source board::mini development tools include a board and expansion boards that will aid your application. BMC labs have introduced a development board based on the STM32 MCU and supporting expansion boards to increase the capabilities of the baseboard via a crowdfunding project.
As mentioned earlier, the board:mini base development board features an STM32 MCU at its heart and comes with a CAN transceiver. For those who do not know what a CAN transceiver is, it just transmits and detects data on the CAN bus. The board:mini project also includes three expansion boards designed to fit on top of the base development board.
The bmc::board project was born to produce development tools appropriate for both field- and industrial-prototyping work. These boards were not designed to sit on a workbench. We ourselves have a habit of strapping them to vehicles, but…the qualities that make them suitable for our purposes translate quite nicely to other fields as well.
The compact form factor board gets a MicroSD card slot, a 24 V power supply, an atmospheric sensor, and USB Type-C support. This hardware is versatile thanks to the in-house support of expansion boards, allowing you to explore the world of hacking. If the base development board is compared to the famous Adafruit feather M0, the board might lack some features. It all depends on the application as the base development board has a higher clock frequency than the Adafruit feather M0 but less storage space. However, the base development board is marketed through additional features, including an atmospheric sensor and a CAN transceiver.
- MCU – STM32F103CBT6, an ARM 32-bit Cortex-M3 CPU Core @72 MHz maximum frequency, with 128 Kbytes of flash memory, 20 Kbytes of SRAM
- Storage – High-quality micro-SD card slot
- Sensor – MPL3115A2 ambient condition sensor by NXP
- CAN transceiver – SN65HVD CAN transceiver by Texas Instruments
- Connectors – Industrial grade board-to-board connectors and USB Type-C connectors
- Power supply – 9 to 24 V power supply (3.3 V and 5 V can be used as well)
To add more capabilities to the base development board, there are three additional expansion boards. The mini::out expansion board is a breakout board that includes 12-pin headers, but the most distinctive feature is the “custom out::cable for connecting your mini::out to an ST-Link/V2 programmer”. The breakout board will allow you to access the CAN bus that communicates between the microcontrollers and devices.
You will have to buy the connector separable from Amazon or eBay. The next expansion board is the mini::grid is integrated with a Quad-Band GSM/GPRS module to track assets at any location and time. The onboard module is expected to give GPS precision of up to < 2.5 m in optimal conditions. The manufacturer provided several connectors, including a display connector, antenna connector, and Nano-SIM connector.
The last expansion board, mini::pit is expected to be widely used because of its Espressif ESP32-WROOM-32U with Xtensa 32-bit LX6 MCU allowing wireless connectivity through Bluetooth low energy (BLE) and Wi-Fi. Even this board provides an SN65HVD CAN transceiver.
All the boards discussed are open-sourced. The manufacturer provides the project design files in a GitHub repository, where you’ll also find instructions to get started with Arduino, PlatformIO, and Rust in the Wiki section. The board::mini development tools project is still live on Crowdsupply, and you can take the benefit of purchasing the early bird board::mini starter bundle that includes one mini::base, one mini::out breakout board, and one out::cable, priced at $65. You can also purchase the expansion boards and base development board separately; however, the devices are expected to be shipped by August 14, 2021.
Abhishek Jadhav is an engineering student, RISC-V Ambassador, freelance tech writer, and leader of the Open Hardware Developer Community.