Arduino

A benchtop spin coater with closed-loop speed and acceleration control, built from catalogue parts for about ₹3,000.

Arduino · Embedded C · PID control · Gain scheduling

Two ultrasonic sensors in a doorway, an Arduino working out which way you walked, and a NodeMCU putting the room’s occupancy on the internet.

Arduino · NodeMCU · HC-SR04 · Adafruit IO