Note: Please scroll down to see all details of this project below ↓
Touch-Free Switches
Objective of This Project
As part of the final independent project for my Electronics Lab, I want to build something that can be useful for our society today. The primary use of this circuit in our daily lives is to function as a touch free-switch for hygienic purposes, whereby, traditional switches present a lot of risks that could potentially affect our health in the long term. However, the circuit that I’ve designed can do something much more than just turning ON/OFF an LED, instead of putting our output as ordinary LED we could potentially connect it to other electric devices. This includes but is not limited to, a touch-free fan, a fan that can be operated by hand movement, a touch-free automatic door, a security system, and other industrial applications.
Designing my Touch-Free Switches on NI Multisim
I design this circuitry on NI Multisim. The main component here is the LM555 Timer used in an “astable mode” for the “trigger mode” and "monostable mode" for the "timer mode" of the touch-free switch. In an “astable mode,” the timer will act as an oscillator that generates a square wave with a specific frequency depending on the values of the resistors and capacitor used, which allows us to trigger the output as HIGH or LOW. Whereby, in “monostable mode” will allow the timer to generate a pustulating output which allows us to give the circuit a specific time duration.
putting everything together
After testing if my circuits for both "trigger mode" and "timer mode" is working properly on NI Multisim, I then started building all the circuitry on a separate breadboard for each of the modes. Whereby, both circuits are working properly as expected. In this case, instead of attaching the output to something like a motor or a fan, I attached it to something much more simpler like a yellow and blue LED (however, we can change the output to something more useful) representing different modes.
Touch-free switches
Final Demo
This is the final demo of my touch-free switches project. There are two modes for this circuit built separately, one is "trigger mode", pressing a button to turn something on, and another one is "timer mode", pressing a button and it will switch off at a specific time depending on the resistors and capacitors values.
