## 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](http://publiclab.org/tag/coqui).
## Latest version
We'll be posting an update soon but the latest and simplest version of the Coqui can be seen in these images as well as the printable circuit diagram file.
[](/i/28988)
[](/i/28989)
[](/i/29461)
## Activities
This is a list of community-generated guides for specific applications using your coqui. These [activities can be categorized](https://publiclab.org/wiki/activity-categories), 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.
[notes:grid:coqui]
Add an activity or request an activity guide you don't see listed
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## Frequently Asked Questions
[questions:coqui]
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[](https://i.publiclab.org/system/images/photos/000/007/410/original/coquibb.JPG)
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
- The github repo for a more permanent printed circuit board version of the coqui is [here](https://github.com/OpenWaterProject/coqui)
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](http://publiclab.org/notes/donblair/09-30-2014/coqui-bbv1-0-testing-conductivity-of-a-solution):
- [Reacting to an LED with sound](http://publiclab.org/notes/donblair/09-30-2014/coqui-bbv1-0-reacting-to-an-led-with-sound):
- [Assessing ambient light levels](http://publiclab.org/notes/donblair/09-30-2014/coqui-bbv1-0-assessing-ambient-light-with-a-photoresistor):
- [Assessing temperature with a thermistor](http://publiclab.org/notes/donblair/09-30-2014/coqui-bbv1-0-using-a-thermistor-as-a-temperature-probe):
- [Sending water quality voicemails with a coqui using vojo.com](http://publiclab.org/notes/donblair/09-10-2014/water-quality-coqui-voicemails):
[](http://publiclab.org/notes/donblair/09-10-2014/water-quality-coqui-voicemails)
### Building your own Coqui
- [Coqui BBv1.0](http://publiclab.org/notes/donblair/09-30-2014/coqui-bbv1-0): a breadboarded version of the Coqui
### Building Coqui sensors
- Making a conductivity probe from a [bottle cap and two metal screws](http://publiclab.org/notes/donblair/09-30-2014/making-a-diy-conductivity-probe-from-a-water-bottle-and-metal-screws)
## Parts list
See the initial parts list here: #13459 and #11209 for a DigiKey shopping cart link at $19 per kit. And @kanarinka mentions:
> there are a couple other things that are helpful to have that are not shown (like the probe made from the top of a water bottle with two screws in it and alligator clips to attach that to the breadboard)
Scans of an invoice from DigiKey:
[](https://publiclab.org/system/images/photos/000/023/760/original/Screenshot_2018-02-28_at_9.59.17_AM.png)
[](https://publiclab.org/system/images/photos/000/023/761/original/Screenshot_2018-02-28_at_9.59.46_AM.png)