Switch boards are from long time and it has been a very essential part of our life. We use then day to day and will be using it forever. With years of development the switch boards have enhanced. In this article we will build a project which is touch based switch board using TTP223.
In this project we will use a touch sensor to power on and off home appliances. These switches will be not like traditional switch. This project is very interesting and will give you a concept of interfacing these touch sensors with AC appliance to control them.
Disclaimer: This project involves working with AC appliances. Please proceed only if you have proper knowledge of working with AC connections. Direct contact to AC voltage can cause death. IoT Starters take no responsibility if any damage happens. If you are not sure please contact a professional or take a help from a professional to connect AC appliances.
TTP223 Capacitive touch sensor module
This sensor is very easily available in online and offline stores. It is cheap and economical as well. It has 3 Pins as in Vcc, Output and Ground. This touch module is 3.5 V – 5.5 V tolerant. You can add a ceramic capacitor to change the sensitivity.
The TTP223 is a touch pad detector IC. This works with single touch at time. This touch detection IC is developed to replace traditional switches. It consumes low power and has wide operating voltage. Due to this features, this module can be used for various DC or AC application.
At the back of the module you could see two jumpers named A and B. Combination of these two jumpers configure this module as momentary switch or on/off switch.
|Open||Closed||ON/OFF on Touch||High|
|Closed||Closed||ON/OFF on Touch||Low|
The TTP223 is a touch pad based detector 6 pin IC. This acts as a tactile switch. This module can easily replace traditional switches.
- Input Voltage range: 3.3V – 5.5V DC
- Compact Module size: 15mm x 11mm
- Detection of touch is stable and efficiency is good
- Simple to interface with Arduino and other development boards
- At low power mode typical 1.5uA, maximum 3.0uA
- Sensitivity can adjust by the capacitance(0~50pF) outside
Below parts are easily available in electronic stores.
- Capacitive Touch Sensor Module TTP223 x 1
- 5V DC Relay x 1
- Led Any color x 1
- Transistor BC547 x 1
- Diode 1N4007 x 1
- Resistor 330Ω, 1KΩ x 1
- Jumper Wires
- 5V DC Power Supply
Uses of Parts:
Touch Sensor Module TTP223 :- This is used to detect the touch.
5V DC Relay :- For Switching and controlling AC load
Led :- For indication
Transistor BC547 :- For switching Relay
Diode 1N4007 :- Works as Freewheeling diode and stops reverse current flow
Resistor 330Ω, 1KΩ :- For limiting the current
5V DC Power Supply:- Powering up whole project
Understanding this circuit diagram is easy and simple. This contains a handful of components which is easily available. You can use a PCB to build this circuit. If you are not sure about connecting AC appliances then take help from a professional.
Building this project is simple and easy. Any beginner can build this. You can build it on a bread board and later you can frame it on a PCB. Here we have used a 5v DC relay module connected with a capacitive touch sensor to build a Touch Based Switch board using TTP223.
Since we need the module to act as a ON/OFF switch, we have kept A open and B closed. This enable the circuit to self lock mode after touch. If you want to keep it momentarily switch then you can keep both A and B as open.
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After connecting all components as per circuit diagram it’s time for testing. Here, we have already build a 5V DC relay module for testing electronics circuits. Touch Based Switch board using TTP223 is ready for testing. Now based on the results
- The relay and the LED will get activated, when we touch the Touch Sensor Module.
- It will be high till the time the touch sensor module is touched again.
- Which means in one touch the relay will be high and in second touch the relay will be low.
- As a result this will act as switch and the corresponding device/ appliance connected to relay will turn on and torn off respectively.
This project is economical and simple to build. This project is perfect for a beginner. This touch module is easily available in the market. The touch module will be behind a non-metallic substance. Hence the risk of electric shock is negligible. You can build this project and comment on how you are using this project. You can share if you make some more advancements and make it multipurpose.