GOLEM keyboard project

Arduino Pro Micro LED pins

The Arduino Pro Micro is one of the most popular controllers for DIY keyboard building. If its 18 GPIO pins prove to be insufficient for some projects, you can utilize the two LED pins.

The Pro Micro wastes the B0 and D5 pins of the MCU for two onboard LEDs indicating TX/RX communication.

For many projects, two more pins seem much more useful than this LED feature, so you can desolder the resistors of those LEDs (or solder directly to the resistors without removing them).

Pic: Two pins wasted for LEDs

While the Atmega32u4 MCU features 26 GPIO pins, the Pro Micro itself makes only 18 of them easily accessible. If this is a limiting factor in your keyboard or other DIY electronic project, you can buy a microcontroller with more pins (like the Teensy, Proton C, Elite C etc.), but for much more money.

Another options is to grab your soldering iron and make two more pins available desoldering the LED resistors.