Simplest ultrasonic ANTISPY voice recording jammer based on ARDUINO module with PWM (optionally AD8933 signal generator) with output MOSFET stage (or H-bridge+MOSFETs) driving piezo ultrasonic transducers + coils

Patches to enable 15KHz video output

Arduino project controlling a PWM PC fan with a rotary encoder, monitored on a small graphics LCD.

Arduino-Based Pump and Fan Controller (OOP, 25 kHz PWM, Separate Hysteresis & Curves for Normal/Benchmark Mode)