About: Hi, I am bharat .

hi in this tutorial i am going to show you how i made a ir motion sensor alarm.

Step 1:

this is a simple transistor based circuit here i use two ir led and one ir photo diode.second ir led IS CONNECTED with buzzer parallel through a switch.

Step 2:

this ir led creates a latch because of it our buzzer continuously on even after object is not available.

Step 3:

as i mentioned if we want to stop alarm we need to reset it

with this switch.

Step 4:

here is the circuit diagram for better understanding

Step 5:

now we can test it. you can watch video to understand how it works.