I had an idea of making a 7x4 touch panel that would have 28 touch points using 11 touch inputs on the Teensy3. Here is a very simple sketch of a portion of my idea:
Each "button" would consist of two concentric copper tape squares, which are the brown squares in the diagram. I would have a wire for each row and column, represented by the red lines. The inner squares would be soldered to the column wires. The end of the wire would be simply soldered, and then at each junction with subsequent squares, I would splice in a wire that would solder to the inner square. I would do something similar for the row wires as well. The red blobs in the diagram represent where I would be soldering a connection.
In code, I would then check each row and column wire to check for a delta in the touch values to determine which row and column are active, to pinpoint which button is being pressed. I only want to support single touch, so if more than one "button" is being touched, I don't care if I can't determine which exact button was pressed.
I want to know if my idea would work. My main concern is crosstalk between different rows and columns. Would a touch at C1R1 induce a touch reading in R2? I would imagine some amount of change would be registered and I'd have to play with square size/separation distance.
I welcome any thoughts/suggestions to make this work before I go about trying it out.
Each "button" would consist of two concentric copper tape squares, which are the brown squares in the diagram. I would have a wire for each row and column, represented by the red lines. The inner squares would be soldered to the column wires. The end of the wire would be simply soldered, and then at each junction with subsequent squares, I would splice in a wire that would solder to the inner square. I would do something similar for the row wires as well. The red blobs in the diagram represent where I would be soldering a connection.
In code, I would then check each row and column wire to check for a delta in the touch values to determine which row and column are active, to pinpoint which button is being pressed. I only want to support single touch, so if more than one "button" is being touched, I don't care if I can't determine which exact button was pressed.
I want to know if my idea would work. My main concern is crosstalk between different rows and columns. Would a touch at C1R1 induce a touch reading in R2? I would imagine some amount of change would be registered and I'd have to play with square size/separation distance.
I welcome any thoughts/suggestions to make this work before I go about trying it out.
