Hello there!
An rookie in electronics could use some help here =).
I'm attempting to hack an electronic piano to read the keystrokes into an arduino and do stuff with it.
On opening the piano I found two pins per key that, when I put my multimeter to them, generate around 2 volt when the key is pressed.
So I soldered wire to these to connect to a breadboard (see picture 1).
The second picture shows the circuit I made for one sensor.
This works perfectly, I can analogRead the force sensor and display them in my serial monitor; I get values of around 900 when a key is pressed, and values less than 70 when the key is not pressed.
However, when I connect a second force sensor (third picture), I'm getting the following problem:
When I press either of both keys, they both sound. When I disconnect their GND's, it's not the case anymore. So apparently a shared ground makes that generating current on one force sensor-circuit, also puts current on the second one, making it sound?
Pressing one key also makes the second sensor read 250 even though it's not pressed.
I guesss I have to separate some things somewhere, but I have no idea what. Or should I put a diode somewhere in there?
I hope I'm making this clear.
Thanks in advance for any help!
PS. I don't need the velocity of the note, just whether or not it's pressed. If all else fails I'm gonna try and connect push buttons to the keys but I'm sure there's a way to hack into the existing circuit...
