If you have one ultrasonic sensor and a microcontroller, you can detect plenty of useful things, like the water level in a rain barrel or the distance traveled by a tablet along a rail.

Posted in Arduino Hacks Tagged adafruit wave shield, arduino, ultrasonic, ultrasonic distance sensor, wav shield ← Fabricate Your Own 7-Segment Displays Easy Capacitive Touch Sensors In Eagle → ...

A low-cost (~$100), do-it-yourself (DIY) ultrasonic water level sensor/datalogger has been designed, constructed, and tested for use in education, citizen/community science, and research settings. The ...

The compact module helps us to test HC-SR04 modules quickly without a costly microcontroller setup (no code lines/solder smokes) and/or build an extremely portable minimalistic sonar device. I have ...