Saturday, October 24, 2009

The Spooky Jack-O-Lantern using capacitive touch sensor - Halloween Special

As we all know Halloween is approaching and so do the spooky ideas Its easy to scare someone when you have this "Spooky Jack-O-Lantern" in your house. If someone tries to reach in and grab the treat Bowl lights up!

This spooky project is powered with AVR Microcontroller which uses a capacitive touch sensor/proximity sensor to detect presence. Capacitive proximity sensor is designed using two aluminum foils act as plates of a capacitor, which creates an electric field when voltage is applied across them.

This Capacitor is connected to microcontroller pin which actually charges capacitor and then measures capacitor discharge time through resistor. If someones hand is near foil capacitor Capacitance decreases (human body = water, electric field strength reduces and hence the capacitance) and it takes longer time to discharge – this is what AVR comparator detects.

No comments:

Post a Comment