ESP32 Forum

Hi,

I tried using esp32 touch sensors and have a few problems. I tried following the instructions in the esp32 datasheet: Appendix A - Touch Sensor. The diagram shows a capacitor b/w ground and esp32 pin. But as soon as I add a capacitor the system immediately registers a touch? Is there any documentation on what the value of capacitor should be? Is that diagram even correct?

I also noticed that the sensitivity is really low. You have to really touch and press for this to activate. And it does not work well at a few mm distance. Most online touch hacks are really using touch on an electrode which is separated by a small dielectric like a tape and no capacitor. Has anyone tried to do this at 3-5mm distance? I want to add a glass/fibre panel and use touch from that.

The documentation also tells not to have any components below and near the electrodes. I want to use an led to indicate the status of of the touch switch. Preferably as a circular led light. Is this possible?

--
Thanks,
Harish

The touch sensors must be covered by an insulator (forming the capacitor dielectric). In general this is the plastic cover of the front panel, with the PCB and the electrodes right behind. If you cannot stick the PCB behind the panel, you can use springs. I think I have a nice document about capacitive sensors design, if I retrieve it I will send you a link to my cloud storage.

Thanks Franco. The design doc for capacitive sensor design would be much appreciated.

Good morning, friends.

I have been looking for the same info: the touch sensor capacitance. Is there any docs from Espressif that tells us this information? Actually, is there any internal capacitor for the touch sensor hardware? Does it do hardware-calibration?

Thanks in advance.