Jeremy Cook
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Liberate your next electronics project from the constraint of wires and run current through a painted line of graphite instead. A DIY graphite paint won’t conduct electricity as well as a wire or an expensive commercial conductive ink. But it’s perfectly good for connecting LEDs to batteries in flexible circuits and making a sheet of paper touch-sensitive enough to play like a piano keyboard.

Materials

  • Powdered graphite
  • White vinegar
  • Syringe
  • Elmer’s clear glue

Stats

Time: 2 hours

Cost: $12

Difficulty: Easy

Instructions

  1. To make the ink, put powdered graphite in a cup, cover with vinegar, and stir. Let it sit for a few minutes.

  2. Once the graphite settles on the bottom of the cup, remove the clear liquid on top with a syringe.

  3. Stir in about a teaspoon of glue to keep the graphite suspended. A thick line of paint has a resistance of a few kilohms per inch.

  4. To test, use a small brush to draw lines connecting a 3-volt coin cell battery to an LED. Let the circuit dry and watch it light up!

This article was originally published in the January 2015 issue of Popular Science.