Chris got his hands on a Crazyflie nano quadcopter. Oddly enough the quad already comes with open source firmware and hardware ideal for hacking ( imagine that! ) So that’s just what he did. The Crazyflie runs a STM32 (arm cortex m3) processor and FreeRTOS. He got the upgraded package with a magnetometer, and altimiter, and can add a GPS too. All things that are great for autonomous flight but it still isn’t smart enough to not bash into the wall.
Adding a proximity sensor would at least help with immediate obstacle avoidance (and walls), So he found a proximity sensor and dove right in learning C again. Check out the full write-up here.