This is my first Instructable and my first summer project. This is a Pressure Sensitive LED Card driven by a 3 Volt battery and a basic transistor circuit which senses the resistance between the two probes (the foil). Luckily as you press harder the transistor allows for more current to reach the LED this is a neat effect and something which I thought my girlfriend would appreciate. As such I decided to make this simple circuit I was studying into a card for here and in the process document and write up the process.
I included an EAGLE Schematic file of the schematic and a pdf version. Furthermore I have those files hosted on my github account
. The schematic was taken from the circuit used in MAKE Magazine's Introduction To Transistors video.
The video is a good basic introduction to transistors. However, I don't really understand the inner workings of transistors so I am going to avoid in depth discussions of transistors, instead resorting to links to explain a little more about transistors.