circuits in play dough | that conference 2015
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Post on 19-Aug-2015
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- 1. @scichelli #thatCircuits Facilitated by Sharon Cichelli Principal Technical Lead Headspring in Austin, Texas With thanks to Squishy Circuits University of St. Thomas http://www.stthomas.edu/squishycircuits/ Circuits In Play Dough
- 2. Try this! If the blobs touch, the LED wont work.
- 3. Building a Circuit A circuit is an unbroken loop for electricity to flow through. Use the dough to connect each LED leg to a battery terminal. But dont let the two clumps of dough touch each other. Thats a short circuit. Not lighting? Flip the orientation of the LED. Nothing special about the dough; salt water conducts electricity. (See recipe next.)
- 4. Mix: cup water tablespoon vegetable oil food coloring Stir that into: 1 cup flour cup salt Mix it, then knead it with extra flour until it is the consistency of fun. Conductive Play Dough
- 5. Motors! And buzzers!
- 6. Motors and Buzzers 9 volts is too much for these motors. They shut down to protect themselves. Each AAA battery is 1.5 volts, so two together gives 3 voltsjust right. Use foil instead of dough. The dough has a high resistance, so it starves the motor of enough current. The foil is more conductive. The buzzer motor is like the one in your phone.
- 7. Watch out for short circuits Battery terminals connected directly to each other get hot! An LED connected directly to the battery ruins the LED.
- 8. Short Circuits A short circuit happens when current flows through a different path than the one you wanted. In the LED + dough circuit, if the dough blobs touch, current will go there instead of through your LED. So the LED doesnt light. Foil has much less resistance than dough; foil lets more current through. LED + foil, the LED gets more current than it can handle. Permanently. Did you fritz an LED during the workshop? Dont sweat it; they cost pennies. Now were learning about current!
- 9. Keep making circuits! The recipe is a few slides earlier. Batteries, battery holders, LEDs, motors, speakers, sensors can be found on Amazon, eBay, Adafruit.com, Sparkfun.com, and at Frys and Radio Shack. (Shush. I miss the Shack.) These LEDs are through-hole (not itty bitty surface mount), 10mm diameter (5mm is fine), and have a forward voltage (minimum volts to work) of about 2.7 volts.
- 10. Thanks to our sponsors!
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