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Touch Detector using Arduino TTP223 Capacitive Touch Sensor

In order to design a touch detector, we “interfaced TTP223 Capacitive Touch Sensor Switch with Arduino” in this project. It is a simple DIY project that uses a single touch to switch circuits. By connecting a relay to the touch sensor, any household appliances can be controlled.

The project’s application areas include consumer products, button key replacement, and waterproofed electric products. A switch is required to operate electronic gadgets. When we operate electrical switches with moist palms, it occasionally causes a shock. A touch switch might be required for some projects since electronic loads are much more interactive than standard switches. This experiment uses an Arduino interface for a digital capacitive touch sensor.

Components Required:

  • Arduino Uno Board
  • TTP223 Capacitive Touch Sensor
  • LED or Buzzer
  • Connecting wires
  • Breadboard

TTP223 CAPACITIVE TOUCH SENSOR

A capacitive touch sensor module based on the dedicated TTP223 touch sensor IC. The module offers a single integrated touch sensing area with a sensor range of approximately 5mm, measuring 11 x 10.5mm. The sensor’s activation will be visually indicated by an on-board LED. The output of the module will change from its off state of low to high when it is triggered (default operation). Its mode of operation can be changed to be either active low or toggling output by using solder jumpers.

Arduino TTP223 Capacitive Touch Sensor Switch

This single-channel capacitive touch screen is easy to interface with any microcontroller, Arduino, or even work without any. When a capacitive load comes in contact with the sensor pad, the sensor detects the change in the capacitance. This change in capacitance activates the switches. These custom sense pads are designed from any conducting material and this sensor touch through the layers of a non-conductive material such as glass, plastic, fabric, or even wood.

Features

  • Power supply for 2 ~ 5.5V DC
  • Output high VOH: 0.8VCC V
  • Output low VOL: 0.3VCC V
  • Response time (touch mode) : 60 mS
  • Output Pin Sink Current (@ VCC = 3V, VOL = 0.6V) : 8 mA
  • Output pin pull-up current (@ VCC = 3V, VOH = 2.4V) : 4 mA
  • Response time (low power mode) : 220 mS
  • Low power consumption
  • Can replace the traditional touch of a button
  • Four M2 screws positioning holes for easy installation
  • Size : 24 x 24 x 7.2 mm

Internal Structure:

The TTP223 is a single-key touchpad detector IC that can identify differences in capacitive elements. It uses extremely little power and only operates in the 2.0V to 5.5V range. At VDD=3V, the response time maxes out at 60mS in rapid mode and 220mS in low power mode. The capacitance (0–50pF) outside can be used to modify sensitivity.

Working Mechanism of TTP223 Capacitive Touch Sensor

Capacitive displays do not alter the flow of electricity using the pressure of your finger. They instead work with everything that can conduct electricity, including human skin.

A small electrical charge is transmitted to the finger when a finger strikes the screen, completing the circuit and causing a voltage drop at that location on the screen. The software analyses the voltage drop’s location and issues the order for the subsequent action.

Touch Detector using Arduino TTP223 Capacitive Touch Sensor Switch

Connections:

Do the connection as follows:

  • Sig Pin of TTP223 Capacitive Touch Sensor ——————- Arduino Digital Pin D7
  • Vcc Pin of TTP223 Capacitive Touch Sensor ——————- Arduino 5V
  • GND Pin of TTP223 Capacitive Touch Sensor ——————- Arduino GND
  • LED positive pin ————————————— – Arduino Digital Pin D13
  • LED negative pin ————————————— – Arduino Ground Pin

Circuit Diagram:

Arduino TTP223 Capacitive Touch Sensor Switch

Arduino Source Code:

#define ctsPin 7 // Pin for capactitive touch sensor
int ledPin = 13; // pin for the LED
void setup() {
Serial.begin(9600);
pinMode(ledPin, OUTPUT);
pinMode(ctsPin, INPUT);
}
void loop() {
int ctsValue = digitalRead(ctsPin);
if (ctsValue == HIGH){
digitalWrite(ledPin, HIGH);
Serial.println(“TOUCHED”);
}
else{
digitalWrite(ledPin,LOW);
Serial.println(“not touched”);
}
delay(500);
}

Conclusion:

I hope all of you understand how to design a Touch Detector using Arduino TTP223 Capacitive Touch Sensor. We MATHA ELECTRONICS will be back soon with more informative blogs.

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