Squishy Circuits


Around here we’re very interested in finding new ways to make electronics more approachable. While we think it is very important to have the opportunity to play with the tools of the trade, placing a scalding hot soldering iron into a child’s hand can be a bit reckless and we don’t want to see you end up on the evening news. So, how do you make basic electronic circuits exciting for kids (and, let’s face it, everyone)? Well, you make it squishy.

Squishy Circuits are the brainchild of AnnMarie Thomas, a professor at the University of St. Thomas and director of the UST Design Lab. AnnMarie leads a team of students looking at both the playful side of engineering (squishy circuits for students, the science of circus, toy design) and ways to use engineering design to help others (projects in technology design for older adults). You can learn more about AnnMarie at her website.

Drawing inspiration from Leah Buechley’s LilyPad collection of sewable circuits, AnnMarie had the idea of sculpting circuits. The original idea was a squishy breadboard consisting of conductive and insulating layers. Together with Sam Johnson, a summer research student, they came up with the idea of highly conductive and insulating doughs that could be used to build circuits. They collected a handful of common homemade dough recipes and checked resistance. A great deal of research was carried out that summer carefully measuring the resistance of the dough over time. Results from these studies created a pool of data from which the group was able to hone in on the perfect recipes as well as present to the scientific community.

We discovered Squishy Circuits while watching AnnMarie Thomas’s TED talk, “Hands-on science with Squishy Circuits.” The nature of the talk and call to play were right in line with SparkFun values and so the next day we whipped up our first batch of conductive and insulating doughs. We set up all the materials in the education tent at this year’s AVC and watched in excitement as people of all ages strolled into the booth to check out the Squishy Circuits. There’s no denying it, everyone wants to play with this stuff.


An hour of playing with Squishy Circuits will tucker just about anyone out.

Having a fun way to introduce fundamentals of electronics and circuits to people of all ages is an incredible tool to share. We recently had the pleasure of working with a SparkFun family member, two year-old Daphne, who was willing to come in for an afternoon Squishy Circuits play date. Daphne was a wiz at putting together the Squishy Sound Circuit and we all enjoyed her sweet jams. Watching a two year-old begin to grasp the concepts of electricity is truly awesome and, yeah, pretty darn cute.

There is an amazing opportunity to tap into the imagination from the color of the dough all the way to circuit design. We had a ton of fun just playing with the food coloring to get bright dough (as evidenced by our bright purple conductive dough and flashy red and green insulating dough) and that was before we ever even built a circuit. We’d love to see what you come up with so please send any projects to education@sparkfun.com. 

We have included recipes below for creating the conductive and insulating doughs with a few tips and tricks from their creator, AnnMarie. We’ve also included a link to a wish list of parts used in the circuits presented in the video. While the recommended lifespan of the doughs is about one month, they can be frozen for long-term storage. You might just find a few Ziplocs full of colorful dough tucked away in our SparkFun freezers – the Department of Education is always prepared to play!

You can learn more about Squishy Circuits on their homepage and Facebook page! If you'd like to make your own, download the recipe PDF and the source code ZIP file for the examples from the video!

General tip: We recommend adding spade or fork terminals to the ends of the wires. By crimping or soldering on these terminals, you greatly improve the surface area. This trick greatly improved our Squishy Circuits at SparkFun!

We’ve created a wish list that includes many of the items used in the circuits highlighted in the video above. This is just a basic list and we encourage you to invent exciting new Squishy Circuits using motors, sensors, etc.

And, while we’re at it, we just want to take a minute to highlight another cool project that came our way recently from Michael Candy. Michael came up with this project when he was creating a sound installation using an infrared range finder that changed the frequency of a speaker according to proximity of the viewer. The range finder worked by sending an analog signal so he thought of trying a fruit instead of the range finder and it worked awesomely! When creating the keyboard some of the fruits and vegetables had very similar sounds so he altered the effect by changing what metals were used when connecting the fruit (brass screws, galvanized nails, stainless steel etc.)


Comments 23 comments

  • Is that GLaDOS attached to that potato in the back?

  • My kids had a blast playing with the squishy circuits and making throwies at AVC. Now that I have the recipe, we’ll have to make some over the summer. Thanks!

  • Those vegetables almost sang “God Save the Queen.” Chance?

  • The squishy circuits look fun, I’ll have to try this with my nephew.
    I envision extruding rods of this with a Playdough Fun Factory ® and laying out multi-layer boards…

  • Never call something a “sandwich” to a kid unless you want them to eat it. Just sayin.

    • Fair enough - though it wouldn’t hurt them one bit. In fact, we did a little testing just to be safe, and I don’t think most children would fancy the flavor much. Then again, I remember a few of my peers eating some interesting things growing up…
      :)

    • I agree. I remember my 2-y/o niece saying “Spider!” while watching me eat kalamari and I had to say “noooooooooooo.” Yoou have to be explicit with kids, otherwise… Lord Of The Flies!

  • Finally Playdough for big kids

  • Why did you guys film this in the classes area? I can tell by the purple throwing stars in the background.

  • Its great for electrolysis they make awesome electrodes.
    A great recipe :P

  • Wow. That’s really cool.
    Do you guys have a age range this would be best for? I’d really like to make some of this stuff for some friends kids.

    • Daphne, our Squishy Circuits expert in the video, is two years-old. As far as I can tell, there’s no upper limit - everyone loves this stuff! There’s nothing particularly dangerous about the dough at all so the only caution would be general care with the electronics.

  • That is SO AWESOME. I love how it’s safe for kids to play with and Daphne is sooo adorable.

  • loving the sleepy person at the back of the 2nd picture

  • Is this edible?

  • This is really a great way to teach small kids about electronics engineering

  • I’m glad to see the education department is starting to rise in power. Looking at the SparkFun Organization Chart, it appears as though they will soon overthrow Marketing and Engineering.

  • Hmmm. That “Squishy Circuits” thingy look interesting, but seems limited. I guess that’s the price for simplicity.
    So, would that keyboard be a “kiwiboard” or a “keygourd?”


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