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 ...

[Tobe] has an intervalometer for his camera, but he wanted a device that could trigger the shutter using several different methods, not just time. He calls his creation the Megavallometer, which can ...