A Coqui is a simple, inexpensive, open source device that generates an audible tone that is based on any electric resistance-based measurement. For example, a Coqui can measure:

• conductivity of liquids
• temperature
• ambient light

Build a Coqui

Instructions on the breadboard-based "BBv1.0" edition of the Coqui can be found here:

http://publiclab.org/notes/donblair/09-30-2014/coqui-bbv1-0

Notes:

• For more information about the Coqui, post a question to the "water quality" mailing list here) (also listed in the left sidebar)
• The github repo for a PCB version of the coqui is here

The Coquí is a circuit that allows you to 'hear' the readings from various sensors. Once the Coquí is assembled, you'll be able to 'hear' the conductivity of a solution, the temperature of a room, or the color of a pH test strip.

The design was named (onomatopeically) after the several species of small frogs which have a loud, distinctive call at night.

Demo Coqui applications

• Testing the conductivity of a solution:

• Reacting to an LED with sound:

• Assessing ambient light levels:

• Assessing temperature with a thermistor:

• Sending water quality voicemails with a coqui using vojo.com:

Building your own Coqui

• Coqui BBv1.0: a breadboarded version of the Coqui

Building Coqui sensors

• Making a conductivity probe from a bottle cap and two metal screws