I am building an interactive sculpture which uses capacitive sensing to take readings and control various outputs like sound and lights.
I have followed this topic on arduino to create my circuit: http://playground.arduino.cc/Main/CapacitiveSensor?from=Main.CapSense
I have found that it is difficult for me to get repeatable results and results that are stable enough for me to use for this purpose. The sensor pad needs to be very large and I think this is why I am encountering issues.
I have noticed that there are still a few things which I have not tried yet to improve the stability of the sensor. So before I decide to go down a different route I would like to try them but I am unclear of the following things which are quoted from the link above:
'Research has shown that a small capacitor (100 pF) or so from sensor pin to ground improves stability and repeatability.'
'Adding small capacitor (20 - 400 pF) in parallel with the body capacitance, is highly desirable too, as it stabilizes the sensed readings.'
I was just wondering if anyone may be able to help me out with what type of capacitor I should use to do this? There are so many different types ceramic, electrolyte etc...
Please would someone be able to email me a link to the type of capacitors I should use to stabilise the circuit?
I would be very grateful.