Coqui conductivity sensor
coqui

## 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). ## Latest version The [latest and simplest version of the Coqui](/notes/warren/03-01-2019/build-a-sound-generating-coqui-conductivity-sensor) can be seen in the following images. This version differs from [the previous](/notes/ashkaya/09-17-2016/build-a-coqui-a-simple-water-conductivity-sensor) in a few ways: * smaller, cheaper circuitboard (breadboard) * fewer wires * flatter wires which make it easier to see the circuit However, the circuit is fundamentally the same! Click these images to enlarge: [![IMG_20190123_111639_270.jpg](/i/28988?size=medium)](/i/28988?size=original) [![IMG_20190118_205609_421.jpg](/i/32338?s=m)](/i/32338?s=o) ## Assemble the Coqui Here are a few guides to building different versions of the Coqui: [notes:grid:activity:coqui] ## Coqui versions The Coqui has been refined, remixed, and modified plenty over the years. [activities:coqui-version] ## Modify the Coqui [activities:coqui-mods] ## Do something with the Coqui Once you've built a Coqui, here are a few things you can do with it: [notes:grid:activity:coqui-usage] Add an activity or request an activity guide you don't see listed **** ## Frequently Asked Questions [questions:coqui] **** [![coquibb.JPG](https://i.publiclab.org/system/images/photos/000/007/410/medium/coquibb.JPG)](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): [![water-vmail.png](https://i.publiclab.org/system/images/photos/000/007/409/medium/water-vmail.png)](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: [![Screenshot_2018-02-28_at_9.59.17_AM.png](https://publiclab.org/system/images/photos/000/023/760/large/Screenshot_2018-02-28_at_9.59.17_AM.png)](https://publiclab.org/system/images/photos/000/023/760/original/Screenshot_2018-02-28_at_9.59.17_AM.png) [![Screenshot_2018-02-28_at_9.59.46_AM.png](https://publiclab.org/system/images/photos/000/023/761/large/Screenshot_2018-02-28_at_9.59.46_AM.png)](https://publiclab.org/system/images/photos/000/023/761/original/Screenshot_2018-02-28_at_9.59.46_AM.png) ...


Author Comment Last activity Moderation
WhiteRabbit "Also, FWIW, not all stainless steels are the same. For instance, 316 SS is more resistant to corrosion than 304. " | Read more » almost 10 years ago
WhiteRabbit "You'll probably need to correct for differences in sample temperature. i.e. temperature will affect the conductivity of the salt solution. So, to..." | Read more » almost 10 years ago
DavidMack "seems like a good approach. maybe specify the type of salt: fine sea salt, table salt (with iodine), kosher salt (no iodine), or Himalayan pink sa..." | Read more » almost 10 years ago
neilh20 "Hi Don, looks great procedure, and while not knowing if it actually works - it does give a procedure for establishing a range for a specific set of..." | Read more » almost 10 years ago
unmanaged "I would be glad to send some SS welding rods to you free of charge... you have access to the scope and tools I do not... I planted the garden today..." | Read more » about 10 years ago
bgamari "Over the last few days I've been busily reworking some aspects of the measurement. Now we have a much lower excitation voltage (currently 100mV, al..." | Read more » about 10 years ago
JSummers "Hi Don, I agree with Cversek that you need to keep the voltage difference small. you also might want to look at using graphite electrodes. The ki..." | Read more » about 10 years ago
donblair "Cversek -- wow, thank you!!! What a useful collection of info. Your note convinced Ben to add a dual op-amp to buffer the conductivity output, and..." | Read more » about 10 years ago
kanarinka "nice work - it's great to see that the conductivity measurement is coming along like this! " | Read more » about 10 years ago
cversek "What is the max amplitude of the voltages you are applying across the screws? If this gets too high you could be electrolyzing the water, other io..." | Read more » about 10 years ago
donblair "Just noticed -- in that last plot, it looks like the 'falling times' (top curve) start 'slumping', whilie the 'rising times' (bottom curve) seem re..." | Read more » about 10 years ago