An Arduino Pro Mini drives an LSM303DLHC compass/accelerometer breakout board and a 12-LED NeoPixel ring. The heading is indicated with a red ‘Pixel between two yellow ones.

The creator of the Arduino RF Pro Mini open source development board Etienne, explains a little more about the inspiration behind the project. “ I’ve loved Arduino for years.

Debug pins and RTC battery backup; Arduino Pro 4G Module: Integrated with Portenta family; ... The Mini PCIe form factor makes it a versatile choice for a wide range of applications, ...

He was having trouble getting his Arduino Pro Mini to communicate with an ESP8266 module. ... if you only need 24MHz 8 pins, its actually only $7. but 24 is cutting too close to spy on USB1.0.