Keywish Expansion Board Compatible with Raspberry Pi 2B/3B/3B+/4/Zero Sensor Board 5V 3A Support 8-Channel ADC Reading with MCU

This is an interesting board. It has it's very own ARM processor, just for using the sensors, leaving the RPi's CPU time to do other more interesting things. That is a STMicroelectronics STM32F030F4P6The board doesn't come with instructions, but you can find them by searching Google for "emakefun readthedocs raspberrypi-sensor-board-master"From the documentation, the specs are:Features: Support 8-channel ADC detection Built-in MCU Support Raspberry Pi 2B/3B/3B+/4/zero 5.5x2.1 DC head and terminal block power supply The external sensor voltage 3V3 and 5V can be switched freely Onboard DC-DC step-down chip Wide voltage input: 5~36V Voltage output: 5V Maximum current output: 3AMCU specifications: Working voltage: 3.3V MCU: STM32 IO: 8-channel ADC detection Communication with Raspberry Pi: I2C I2C address: 0x04From the ST datasheet for the STM32F030F4P6. CPU: Arm® Cortex®-M0 32-bit RISC core operating at a 48 MHz Flash: 16KB SRAM: 4KB Timer - Advanced: 1 (16-bit) Timer - GP: 4 (16-bit) COMM - SPI 1 COMM - I2C 1 COMM - USARD 1 12-bit ADC: 1 (9ext + 2 int) GPIO 15 Operating Temp -40C to +85CThere is a lot more information in the datasheet. Search Google for "st stm32f030f4p6 datasheet"The marked up picture is from the instruction sheet. Basically, the yellow section is where the sensors go. The A0 through A7 are analog inputs controlled by the ST chip. The rest appear to be passthrus from the RPi header.This board gives you a nice place to attach your sensors, each with their own + and - power.I could see this board being useful for a lot of sensor and IO heavy projects.

This Emakefun Micro bit Board might be a bit of a challenge. It is a chinese board and all documentation I've found is in chinese, but available in english with translation. It look like it will breakout the Raspberry Pi's signals and has the potential for enhancing the interfacing to the Pi. I'm excited to learn more about this intriguing addon.

This board is great for experimenting with the Raspberry Pi GPIO. This board breaks out the pins of the GPIO allowing easier connectivity of analog sensors by using the STM32 to read the analog signal and perform the ADC to send to the Raspberry Pi. There are 8 channels to use on the board allowing for multiple analog signal inputs at the same time. Great for prototyping or experimenting. It did not come with documentation but can be found by searching for the board on Google. The online instructions walk you through setting the board up on the Raspberry Pi and enabling the I2C communications to talk to the board.