Capacitive Sensor Help

Forum 2005-2010 (read only) Software Syntax & Programs
1

Hello All,

I'm fairly new to Arduino and I've hit a snag. The answer is probably simple but I just can't see it.

I'm working with this code for my Duemilanove ATmega168: Arduino Playground - CapacitiveSensor

I'm basically messing around with the code and using tin foil as my sensor. The read out for the serial has a base value of about 1 or 2. When someone touches the foil, it should go up much higher (no higher than 16 for this particular program). However, the read out value barely changes regardless of someone coming in contact with the foil.

It goes to about 3 when I touch it. It doesn't change at all if I step on the foil. Is this type of sensor only responsive to skin?
I have the foil connect via alligator clip to a resistor which I've fed directly into one of the digital pins. The Arduino is plugged into my laptop and when I touch the sensor with one hand and the laptop with my other hand the read out shoots to 16.

I need a higher read out so that I can use the value in Processing (e.g. if value is greater than 5, send something over a network).

How do I fix this sensing problem. I have tried every combination of resistor and wire imaginable to no avail.
Any help would be greatly appreciated.

2

Hi, maybe you can try with a larger resistor value? I think the larger the resistor(I use Mega Ohm ranges) the better the sensing range

3

Basically this is not a very repeatable technique, it is more of a novelty than a serious piece of electronics. It relies on noise pickup from the air. Serious capacitive sensors are available but they all need a specialised PCB.