Want to make your home look cool and scientific as a smart home. You are at the right place. Today we are going to make automatic Door Bell circuit. This bell is so cool. The buzzer will ring when someone waves their hands towards the sensor. No need to press the old dirty switch.
LM358 IC or any suitable OP-AMP
IR Transmitter and IR receiver(Photodiode)
Resistors (See circuit diagram for values)
Active 5v Buzzer
LM358 is a dual channel op-amp. i.e. we can have 2 channels of input and two outputs. But here we are gonna use only one channel. The IR Transmitter (The one used in Tv remotes) will emit IR light. By applying voltage, we are emitting IR Light from it. The IR receiver in another end will generate a voltage if it receives IR Radiation. This voltage will be applied as the input to the op-amp. When the op-receives this input, it will generate 5v as output which is applied to the buzzer making it ring. So, whenever someone waves their hand IR radiation will hit their hand get reflected and it will reach the receiver. Thus, it will make the buzzer shout. This is all about its working
To Implement this automatic Door Bell circuit practically you need to do some modifications. You will need to buy or make a 220VAC to 9v DC and give it as input voltage as u cannot on 9V battery. Also, you need to reroute the buzzer to place it inside your house. You can also add additional circuits with this to generate some other sounds.