Circuit building and prototyping is getting easier and easier these days! In this Instructable, you'll see how to make a simple touch sensing circuit just by drawing it!
1x Glossy Photo Paper
2x Coin Cell Batteries
1x NPN Transistor
Step 1: Draw the Circuit Path
You can follow a schematic or template, keeping in mind where the batteries are going to be. I just drew freehand using an AgIC marker, but any conductive drawing tool ought to do.
Step 2: Conductak for the Batteries
I stuck a bit of Conductak onto the the circuit where the batteries were going to go. I stuck one battery to each glob, being careful with polarity, and then folded the corner of the paper over and stuck the batteries together with more Conductak. No binder clip needed!
Step 3: Conductak for the Components
Next, stick some Conductak onto the rest of the circuit for your electrical components. Then stick your components on. That's it!
Step 4: Play!
When you touch the pattern in the middle, your skin completes a circuit. The current that passes through your skin would be too low to light an LED, so we use a transistor to amplify the current to a level that can turn the light on.