Introduction
A touch-sensor system is built on a substrate which carries electrodes and relevant connections under a protective flat surface. When a user touches the surface, the capacitance variation is triggered and a binary signal is generated to indicate whether the touch is valid.
ESP32 can provide up to 10 capacitive touch pads / GPIOs. The sensing pads can be arranged in different combinations (e.g. matrix, slider), so that a larger area or more points can be detected. The touch pad sensing process is under the control of a hardware-implemented finite-state machine (FSM) which is initiated by software or a dedicated hardware timer.
Read More on PCB and Touch pad design considerations for best results.
ESP32 Capacitive Touch pins
There are ten capacitive pins available on ESP32 names as Tocuch0 to Touch9.
ESP32 Cpacitive Touch Circuit
Do not connect any capacitor, Ccomponent, Ctrace and Celectrode are representation of capacitors formed in circuit.
ESP32 Capacitive Touch Buttons Code
/* * Copyright (c) 2018, circuits4you.com * All rights reserved. * * ESP32 Capacitive Touch Example */ byte touch; //====================================================================== // Setup //====================================================================== void setup() { Serial.begin(115200); touch_pad_filter_start(T0); touch_pad_set_filter_period(T0); } //====================================================================== // Loop //====================================================================== void loop() { touch= touchRead(T0); Serial.println(touch); delay(100); }
Results
Open serial monitor and observe the reading when pad is not touched reading will vary from 70-80, when touch is detected reading will go to 0-20.