Hi,
as I use multiple Bare Paint inputs (basically I am reading the capacitance from any single object, I have 4 jelly structures in this case) and when I touch JellyA I get good readings and likewise from JellyB, but as I touch both the values increase/double. How can I avoid this?
I got digital pin 2 and 4 connected to a breadboard, 10k resistor between, and a sensor pin to the jelly, further more I have 6 and 8 connected in the same way to another jelly.
Ideas?
No idea what you are talking about.
Got some links to "bare paint" and "jelly structures"?
I remember seeing it on the Adafruit website: Bare Conductive Paint - 50mL : ID 1305 : $34.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Please attach a photo and schematic how it is wired.
And upload your sketch.
Is the jelly conductive ? I don't have jelly lying around to measure it.
Thanks for the extra info.
How large are the jelly structures ? Perhaps they become antennas or pick up the 50Hz/60Hz mains noise.
This is the bare paint company: http://www.bareconductive.com/
Can you place 4 jelly structures with short wires apart from each other. For example with a distance between them that is twice the size of the jelly structure.
Did you read the CapacitiveSensor page ?
http://playground.arduino.cc/Main/CapacitiveSensor
They use a common pin for the signal send wire.
I suggest you use the same as the example.
Use pin 4 as common pin, and the other pins 2,3,5,6.
So pin 2,3,5,6 are the sensor pins to the jelly.
Use 4 resistors from pin 4 to those other pins.
In your sketch do this:
CapacitiveSensor cap0 = CapacitiveSensor(4,2);
CapacitiveSensor cap1 = CapacitiveSensor(4,3);
CapacitiveSensor cap2 = CapacitiveSensor(4,5);
CapacitiveSensor cap3 = CapacitiveSensor(4,6);
The sensor wires does not need to be grounded.
The GND of the Arduino should be connected to earth ground (a water pipe or something like that).
You could try the capacitor of 100pF to 10nF as suggested on the CapacitiveSensor page.
What do mean that you ground them both ?
Do you have a foil under the jelly connected to earth ground ?
Be sure they don't connect to the jelly, and that is almost the same as adding a capacitor.
"Earth ground" is digging a deep hole in the ground, put a wire in it. Or connect a wire to the water service pipes in a house, assuming the metal pipes and the water will be connected to earth ground somehow.
I'm not sure it will be okay in the end. This is radio waves fuzzy science, and everything influences other things. But at least the grounding should help some.