What Does It Do?
The Coqui: a simple device to read a sensor via an audible tone. We're exploring using audio frequencies to convey sensor readings -- like a modem, but even simpler -- in order to make sensor readings more accessible for people (or to enable data transmission over ubiquitous audio jacks on PCs and smartphones). Look for recent updates on Public Lab here.
This is a list of community-generated guides for specific applications using your coqui. These activities can be categorized, and some may be more reproduced -- or reproducible -- than others. Try them out to build your skills, and help improve them by leaving comments. Together, we can repeat and refine the activities into experiments.
|Build a sound-generating Coqui conductivity sensor (new version!)||-||-||@warren||-||-||1 replications: Try it »|
|Building the new Coqui||-||-||@natevw||-||-||0 replications: Try it »|
|Build a Coquí: A Simple Water Conductivity Sensor (version 1)||build||review-me||@akshaya||1h||easy||3 replications: Try it »|
|Build a "Mega Coqui" water conductivity sensor with an amplifier||-||-||@warren||-||-||0 replications: Try it »|
Activities should include a materials list, costs and a step-by-step guide to construction with photos. Learn what makes a good activity here.
Guides should include a materials list and a step-by-step construction guide with photo documentation. Learn what makes a good activity here.
Frequently Asked Questions
|How can we adjust the volume of the coqui?||@liz||over 2 years ago||0||7|
|How can we adjust the frequency of the coqui?||@liz||over 2 years ago||1||4|
|Why does my coqui not change frequency in salt water anymore?||@stevie||11 months ago||0||2|
|Can anyone tell what is wrong with my coqui?||@stevie||about 2 years ago||1||14|
|DIY Salinity Measurements with Coqui and/or Multimeter?||@Bronwen||about 2 years ago||1||3|
|Can we use a guitar tuning app to get numeric data from the Coqui water sensor?||@warren||about 2 years ago||0||3|
|Could we just use the PWM feature of an Arduino to generate the 50% duty cycle we need for the Coqui or for a water conductivity meter?||@roberts_ecofarm||over 2 years ago||1||1|
|Will this single timer work for the coqui?||@asnow||almost 3 years ago||0||5|
|How much are Coqui measurements affected by hot/cold water?||@warren||over 6 years ago||4||16|
|Accessible procedure for calibrating conductivity measurements?||@donblair||almost 7 years ago||2||3|
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
- ambient light
Build a Coqui
Instructions on the breadboard-based "BBv1.0" edition of the Coqui can be found here:
- 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
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