38 Capacitive Touch Sensor
38 : Capacitive Touch Sensor
- Author: Tobi McKellar
- Description: Senses capacitive touches.
- GitHub repository
- Open in 3D viewer
- Clock: 24000000 Hz
How it works
Measures the difference in capacitive time constant when a finger is applied to a touch pad.
How to test
You will need a capacitive touch pad PCB. Alternatively, make your own out of tinfoil! Connect one side of the capacitor to ground, and pull the other up to 3V3 via a large (~1MOhm resistor). The pulled up side should also be connected to UIO0. Reset the ASIC and then put your finger on the pad and observe UO0 rise and fall with your finger presses.
External hardware
Capacitive touch pad PCB
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | BTNO_0. | CIO_0. | |
| 1 | BTNO_1 | CIO_1 | |
| 2 | BTNO_2 | CIO_2 | |
| 3 | BTNO_3 | CIO_3 | |
| 4 | |||
| 5 | |||
| 6 | PTI_0 | PTO_0 | |
| 7 | PTI_0 | PTO_1 |