Coqui Conductivity Sensor
The Coqui is a circuit that allows you to 'hear' the readings from various sensors. With an assembled unit, you'll be able to 'hear' the conductivity of a solution, the temperature of a room, or the color of a pH test strip.
For example, a Coqui can measure:
This version of the Coqui is made on a breadboard, and with just a few simple parts. This kit contains all the parts you need to get started, and learn how to build your own with this page on the Public Lab site!
For an overview and more information: click here