Femtoduino has designed a dime sized (18mm diameter) Wi-Fi/Bluetooth wireless IMU (inertial measurement unit) that runs MicroPython:

FemtoBeacon ESP32-PICO-D4 (4MiB) wireless IMU coin

What is it?

The world’s smallest open-source Wireless IMU. It has an ICM-20948 MPU (9-axis: accelerometer, gyroscope, magnetometer), and an MS561101BA03-50 precision altimeter/temperature sensor.

The coin uses the ESP32-PICO-D4 chip (4MiB) and has all peripherals attached via SPI (hSPI).

Requires a USB to UART adapter that can provide pass-through 5V to coin VIN pin and at least 500mA to 3V3 pin.

Pin Out:

• RGB LED, Red pin: 26
• RGB LED, Green pin: 4
• RGB LED, Blue pin: 5
• hSPI SCK pin: 14
• hSPI MOSI pin: 13
• hSPI MISO pin: 12
• MPU Chip Select pin: 15
• Altimeter Chip Select pin: 27

Why did you make it?

I made these for use in personal projects where I need a very small motion processing unit.

What makes it special?

It’s incredibly small, light weight, and open source!