Coqui conductivity sensor
question: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
Ag8n " The reason multimeters aren't used for measuring the resistance of a solution is polarization. It's a fancy word, but by passing direct current t..." | Read more » over 5 years ago
warren " I also found recently that a more powerful battery makes it louder, which i guess i could've figured out from the comments above (lol) but, just t..." | Read more » over 5 years ago
warren " I think it's possible, yeah! I'm not sure how fast PWM is or how easily you can set the rate? " | Read more » almost 6 years ago
warren "I was also able to confirm that adding a resistor in-line with one of the probe wires lowered the frequency! Much lower and less annoying! " | Read more » almost 6 years ago
xose "Hi @Liz! A potentiometer just before the probe changes tone. And, for a higher volume you can substitute the piezo speaker with a minijack connecto..." | Read more » about 6 years ago
warren "Also if you have a resistor you could test the idea bc a potentiometer is an adjustable resistor, if that's helpful.  On Sat, Nov 3, 2018, 11:58 A..." | Read more » about 6 years ago
liz "Thanks @warren and @roberts_ecofarm! This information is really helpful, and gives a way forward. I will dig through my boxes of extra parts and fi..." | Read more » about 6 years ago
roberts_ecofarm "Changing the frequency range would require either changing the duty cycle of the 555 or modulating the amplitude. I think the the probe (resistor)..." | Read more » about 6 years ago
roberts_ecofarm "Changing volume can be done by adding a potentiometer into the loop. Here is an easy description of how http://www.learningaboutelectronics.com/Art..." | Read more » about 6 years ago
warren "that page does say that: Being that we are using a 555 timer chip, the maximum voltage that a 555 timer can withstand is 18V. " | Read more » about 6 years ago
warren "I'm not sure about this one... but maybe we could look on the web for "increasing amplitude of 555 circuit"? http://www.learningaboutelectronics.c..." | Read more » about 6 years ago
warren "I'm not positive, but since the Coqui is measuring resistance (which reveals conductivity) as in this diagram: https://publiclab.org/notes/donblair..." | Read more » about 6 years ago
asnow "Great thank you Kina! " | Read more » over 6 years ago
asnow "Thanks Chris! " | Read more » over 6 years ago
kinasmith "both parts are very similar. the TLC555IP has a wider operating temperature (-40to+85c), and will work down to 3volt power input. From the datashee..." | Read more » over 6 years ago
cfastie "I am going to guess: Yes, they are interchangeable for your application. DigiKey links to the same data sheet for both of them. Page 3 of the datas..." | Read more » over 6 years ago
asnow "@kinasmith @cfastie @donblair thanks! " | Read more » over 6 years ago
warren "I've submitted a bug report with steps to fix: https://github.com/publiclab/plots2/issues/885 -- sorry! " | Read more » about 8 years ago
warren "I'm actually having trouble editing this page -- must be a bug due to it being "converted" to a question instead of being one from the start. " | Read more » about 8 years ago
warren "Actually i haven't tried marking a question as an activity; i guess it works? Maybe not a good practice? I dunno -- new territory for us! As to you..." | Read more » about 8 years ago
pdhixenbaugh "Also: I'm not sure if you're testing (1) Hot Tap Water vs Cold Tap Water, or (2) Hot Tap Water vs. Hot Tap Water which has cooled down. Put another..." | Read more » about 8 years ago
pdhixenbaugh "So both questions and research notes can be marked as an activity? And at some point, folks replicating the activity can post their answers? I like..." | Read more » about 8 years ago
warren "I renamed this and converted it to a "Question" in the new Q&A system " | Read more » about 8 years ago
GreenChemist "Hi Warren, Thanks. I am a chemical engineer who always worked in Medical and Safety industries. Currently I am looking for a new position anywhere ..." | Read more » over 9 years ago