A embedded development PCB for development of sensor/control type projects. The PCB has a STM32 ARM MCU, LoRa Radio chip and antenna, and bunch of sensors and IO.

Core functionalities:

• MCU : STM32L151CCU6 - see ST datasheet for full details
• SWD pads for programming the STM32
• LPWAN radio : Lora SX1272 + PCB antenna for nominal 868Mhz operation (EU/RU/IN ISM bands)
• accelero : ST LIS2DE12
• altimetre (temp+pression) : ST LPS22HB
• microphone I2S : Knowles
• phototransistor for light level capture
• 2 LEDs, one red, one green
• hall effect MCU reset
• no LDO, uses the 3-3.6V input directly as-is

Connectors:

• 1x 2 pin header for battery (no LDO, direct 2.4-3.6V DC)
• 1x 3 pin header Vcc/Gnd/GPIO with MOSFET drive output PWM for speaker
• 2x 3 pin header Vcc/Gnd/GPIO input/output
• 4 way 2mm pitch header for connecteur type Grove for serial port with Vcc control by GPIO/MOSFET
• 4 way 2mm pitch header for connecteur type Grove for I2C with Vcc control by GPIO/MOSFET

Origin: The device was designed and produced by a company (Wyres SAS in France) who subsequently discontinued the product. This is the remaining stock of boards that were produced but never used. The full schema and documentation are available on a github project for developers.

Firmware: The board has a well developed and very functional open source firmware build available on github, which means that using this product as the basis for a sensor/IO device should be very easy for any reasonably experienced (C firmware) developer. The firmware functionality plus the IO connections mean that adding extra sensor/control outputs should also be pretty simple.

An example project is on hackaday.io using this board, and includes details for building and flashing the firmware.

Obviously it is also possible to just use the hardware and do your own thing for the firmware - its a standard STM32 - the flash/RAM is limited but for C dev its fine.

NOTE: The antenna and tuning components are for the 868MHz band. Althought the SX1272 can be configured to run at different frequencies, only those 'near' to 868MHz will get a reasonable performance - RU and IN bands have been tested as ok. However, 900/915MHz bands will not be usable with this product. In addition, the CE/RF testing is valid only for EU geographies, not for the US (no FCC approval).

WARNING: Note that the product is supplied as a development kit - the MCU is NOT flashed or configured to do anything out of the box, and you will need to be comfortable with creating your embedded image and flashing it to the MCU (see photo example of using an ST-Linkv2 and a clip - NOT included) to be able to use it. Note also that this is NOT an Arduino supported board so you cannot use that eco-system to program it.