Support for WTC401SPI touch sensor

[lanrat]

Describe the problem you have/What new integration you would like

I'm requesting support for the WTC401SPI touch sensor. I've found this touch sensor in some ESP32 based LED lamps for the brightness and color controls.

The datasheet and some example code can be found here.

Please describe your use case for this integration and alternatives you've tried:

I'd like to replace the firmware on some of these LED lamps with ESPHome, but in order to get the inputs working, support for this chip would be required.

Additional context

One lamp that uses an ESP32 and the WTC401SPI is the dlamp.

[lanrat]

Found a similar touch panel which may share similarities with the underlying library: https://github.com/racerxdl/wtc801

[Tomcuzz]

So did some messing around with one of these and was actually able to get this working using a lambda in esphome Code might need a bit of tidying up but a good starting point could be:

spi:
  - clk_pin: <SCK Pin>
    mosi_pin: <SDI Pin>
    miso_pin: <SDO Pin>
    interface: hardware

spi_device:
  - id: wtc401
    cs_pin: <SCS Pin>

binary_sensor:
  - platform: gpio
    name: "Touch Registered"
    pin:
      number: <Flag Out Pin>
      inverted: true
      mode:
        input: true
    filters:
      - delayed_on: 100ms
    on_press:
      then:
        - lambda: !lambda |-
            id(wtc401).enable();
            uint8_t data = id(wtc401).transfer_byte(0xFF);
            id(wtc401).disable();
            if (data == 131) {
              id(power_button).turn_on();
<There are other pins I don’t have hooked up but you can log to check these number>
            } else {
		uint8_t ndata = ((55 - data)* 255) / 53);
            }
    on_release:
      then:
        <Do something when finger released>

[lanrat]

Hey @Tomcuzz, I haven't looked into this in a while. By any chance are you also looking at porting ESPHome to the dLight?