Review on Keywish Expansion Board: Raspberry Pi 2B/3B/3B+/4/Zero Compatible Sensor Board, 5V 3A Support, 8-Channel ADC Reading with MCU by Maurice Vianes

An interesting board. It has its own ARM processor dedicated solely to using the sensors, leaving the RPi's processor time for other, more interesting things. This is STMicroelectronics STM32F030F4P6. There are no instructions on the board, but you can find them by searching Google for "emakefun readthedocs raspberrypi-sensor-board-master". The documentation states the following specifications: Features: Supports 8-channel ADC detection Built-in MCU Supports Raspberry Pi 2B/3B/3B+/4/Zero 5.5x2.1 DC header and terminal block power supply External sensor voltage 3V3 u 5V freely switchable Built-in DC-DC step-down chip Wide voltage input: 536V Output voltage: 5V Maximum output current: 3AMCU Specifications: Working voltage: 3.3V MCU: STM32 IO: 8-channel ADC detection Communication with Raspberry Pi : I2C I2C address: 0x04 From ST datasheet for STM32F030F4P6. CPU: 32-bit 48MHz ARM® Cortex®-M0 RISC core. Flash: 16KB SRAM: 4KB. I2C 1 COMM - USARD 1 12-bit ADC: 1 (9ext + 2 int) GPIO 15 Operating temperature -40C to +85C There is much more information in the datasheet. Search Google for "st stm32f030f4p6 datasheet". The highlighted image is taken from the instructions. The sensors are mainly located in the yellow area. The analog inputs A0 to A7 are controlled by the ST chip. The rest seems passable from the RPi header. This board gives you a good place to connect your sensors, each with their own + and - power supplies. I see this board as useful for many high performance sensor and I/O projects.