Touch Sensor Interfacing with PIC16F877A (TTP223B)

In this tutorial we are going to discuss Touch Sensor Interfacing with PIC16F877A (TTP223B).

Prerequisites

Before start this tutorial we should know below topics. If you know already, please go further.

Components Required

Introduction

The TTP223B is a Digital touch pad detector IC which offers 1 touch key. The touching detection IC is designed for replacing traditional direct button key with diverse pad size. This device uses your body as part of the circuit.

When you touch the sensor pad, the capacitance of the circuit is changed and is detected.  That detected change in capacitance results in the output changing states. In the normal state, the module output  low, low power consumption; When a finger touches the corresponding position,  the module output high, if not touched for 12 seconds, switch to low-power mode.

Specification

  • Operating voltage 2.0V~5.5V
  • ƒOperating current @VDD=3V, no load, SLRFTB=1,At low power mode typical 1.5uA, maximum 3.0uA and At fast mode typical 3.5uA, maximum 7.0uA
  • Operating current @VDD=3V, no load, SLRFTB=0,At low power mode typical 2.0uA, maximum 4.0uA and At fast mode typical 6.5uA, maximum 13.0uA
  • The response time max about 60mS at fast mode, 220mS at low power mode @VDD=3V
  • Provides Fast mode and Low Power mode selection by pad option(LPMB pin)
  • Operating Temperature:-20 ~ +70 ℃

Touch Sensor Pin Outs

Like  a lot of the sensors out there, this is three pin sensor.  You provide, power, ground and monitor the output.

  • SIG – Output (If it detects touch, this will be HIGH otherwise LOW)
  • VCC – 2v to 5.5v
  • GND – Ground

Touch Sensor Interfacing with PIC16F877A

Connection

Touch Sensor

  • Vcc – 5v
  • Gnd – Ground
  • Sig – RD0 (PORTD.0)

LCD

  • RS – RC0
  • RW – RC1
  • EN –RC2
  • Data Lines – PORTB

Touch Sensor Interfacing with PIC16F877A

Source Code

If this sensor detects any touch, LCD will display “Touch Detected”.

References

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