[Mike] lives in a temperate rainforest in Alaska (we figured from his website’s name) and uses a 570 gallon oil tank to supply his furnace. Until now, he had no way of knowing how much oil was left in ...

Ultrasonic sensors measure the distance between a target and the sensor using high-frequency sound waves that are inaudible to humans. The process is simple: the sensor emits ultrasonic waves, which ...