Ultrasonic Rainwater Tank Capacity Measurement Device

Hacker “NikonUser” has a rainwater tank both for conservation reasons and simply to save a bit of money. While the tank itself seems to work quite well, checking the water level was difficult, as he had to climb into a precarious position to peer inside. Although he originally envisioned a solar-powered device that transmits data wirelessly to a web page to help with this task, he decided to scale things back and instead built a widget that he could hold over the tank opening to detect water levels.

His gadget uses an ultrasonic sensor to transmit ping data to an Arduino Pro Mini, and shows the readings on a four-digit seven-segment LED display module. This can reveal how full the tank is in percent, or as the number of liters of water in the tank — 2,000 in his case.

In order to get a precise reading, NikonUser turned to a “Gauge Stabilization and Precision Placement Platform” — aka a block of wood — to position the sensor at a repeatable height above the top opening.

While the enclosure size was a bit of a guess, everything ended up fitting inside. The results are a nicely finished project, with a simple button user interface!