At project start i wanted to use TL-WR703N GPIO’s for direct control. But when i pulled out almost all gpio from openwrt table, i found that only few of that really accessible. So i decide to add simple USB bridge based on sparkfun arduino pro micro (china clone costs less than atmega32u4 on local market).

With this mod it now closer to SatNOGS project, but i don’t like their decision to use CDC and additional serial protocol. My board almost the same as SatNOGS-arduino, but with different wiring, I2C for Adafruit OLED display and voltage divider for battery monitoring.

schematic x-at-arduino control board

Update 14.01.2015: i decided to replace QTR-1RC with QTR-1A (by modifying sensor). Most of tasks now works in x-at-arduino.git firmware.


  • Code cleanup


  • Check stepper drivers
  • Check SSD1306 OLED display
  • Check QTR-1RC endstops
  • Check Vbat voltage meter (A0)
  • Simple LUFA HID device
  • Port AccelStepper
  • SSD1306 support
  • Error indication (LED1)
  • Watchdog enable