Coqui conductivity sensor

## 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](]( 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: ### Notes - The github repo for a more permanent printed circuit board 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]( [![water-vmail.png](]( ### 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]( ## 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](]( [![Screenshot_2018-02-28_at_9.59.46_AM.png](]( ...

Author Comment Last activity Moderation
warren "Hi, all, i finally got it working... you know, I think i'd had a couple things wrong, but also the long wires (although easier to insert) make it r..." | Read more » over 5 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 » over 5 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 » over 5 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 » over 5 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 » over 5 years ago
roberts_ecofarm "Changing volume can be done by adding a potentiometer into the loop. Here is an easy description of how" | Read more » over 5 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 » over 5 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 » over 5 years ago
warren "I'm not positive, but since the Coqui is measuring resistance (which reveals conductivity) as in this diagram:" | Read more » over 5 years ago
warren "I'm having trouble getting our demo Coqui to work -- these breadboards don't really last... but just to break out this one point, @liz - you mentio..." | Read more » over 5 years ago
Bronwen "Hi! The simplest (and cheapest) conductivity sensor I can think of is the Coqui-- we have a recent blog post about it here, and I would imagine wit..." | Read more » over 5 years ago
roberts_ecofarm "Thanks Chris, We have multiple injection well sites in our county, and more in the works, so we are planning on covering a large area. We will be..." | Read more » over 5 years ago
cfastie "You are right that there has not been much follow-through at Public Lab on developing and testing DIY conductivity or total dissolved solids (TDS) ..." | Read more » over 5 years ago
liz "Hi @zengirl2 , you are awesome for re-working the wiring diagram! i just followed your updated instructions in preparation for doing this activity ..." | Read more » over 5 years ago
zengirl2 "This is a great write-up on this activity. As @warren mentioned I did this activity at MakerFaire with a very broad age range 6-60. Because I was b..." | Read more » over 5 years ago
warren "Love this! Super :smiley: Our breadboards didn't have nice Vcc or Ground sections like those pictured in the activity, so we decided to use one ro..." | Read more » over 5 years ago
pdhixenbaugh "For example, one hour is pretty tight. If you introduced and started building the coqui one lesson, and finished building and tested water sources ..." | Read more » over 5 years ago
pdhixenbaugh "+1 for the coqui! I just adapted it for a 2h lesson with 14-17 yr olds. I think it could work well with 6 graders provided you had enough time to g..." | Read more » over 5 years ago
Bronwen "Hi @Kmckeown -- your seminars sound great! I think that the microscopes and Babylegs would be a great fit for something like this.The 3D printer an..." | Read more » over 5 years ago
xose "Hi @jiteovien! So glad you're using the Coqui. At @imvec we're remixing right now a plug and play guide for teachers. Next week we'll be publishin..." | Read more » almost 6 years ago
warren "Love this! :grinning: " | Read more » almost 6 years ago
imvec "hahhahahah!!! added link to the very first line ;D " | Read more » almost 6 years ago
warren "Very cool!!!! Haha for those new here, it's the Coquí, not the frog! " | Read more » almost 6 years ago
xose "A bit late but here is how to plug the jack " | Read more » almost 6 years ago