A wide range RF detector 50-3000Mhz with battery charger, ATtiny micro controller and SMD. This can be used as a linear instrument monitor or as a threshold/comparator alarm.
I wanted a distraction-free way to give my 7 year old a way of quickly contacting me in an emergency, so I built a 2 button cell phone.
Use the Sony Spresense with camera board and LTE board to detect potholes and then notify via MQTT the GPS location!
A computer vision system that detects and localizes the surface cracks in the concrete structures for the predictive maintenance