In this project, I'm going to explain how to make a simple IR proximity sensor using IR LEDs, LM358 Dual Op-Amp and some basic electronic components you can find at any local electronics shop.What Is IR Proximity Sensor?
IR stands for Infrared which is a light with wavelength which is not visible to human eyes but cameras can see it. It is used in many applications such as TV remote and night-vision cameras.
In a proximity sensor, an IR LED and a Photodiode are used to find an obstacle. The IR LED transmits light in forward direction when an obstacle is ahead the light reflects and the Photodiode is activated by this method obstacle is detected.
There are many IR modules available online which are cheap they cost about ₹200 or about $2-3. Which can be used in an obstacle avoiding robot or line follower robot.
In this tutorial, I'm going to show you how to make a simple IR proximity module which will cost about ₹50-60or about $1.Making Connections :-
- Follow the circuit diagram and make the connections, refer to the pictures to make it easier to replicate the design on a breadboard.
- First insert the IC in the breadboard.Next connect Pin no. 4 of the IC to Ground and Pin no. 8 to +5v.
- Now connect Pin no. 2 to Ground.
(If you need to set the sensitivity of the Receiver then you can add a 10k ohm variable resistor to it. Connect the left terminal to Ground and Right Terminal to +5V and connect the central Terminal to pin no. 2 of the IC, Now you can vary the sensitivity using the variable resistor)
- Now take the normal LED and connect it's +ve terminal/Anode (longer lead)to pin no. 1 of the IC. and connect a 100/150ohm resistor to the -ve terminal/Cathode (short lead)and connect the other end of the resistor to Ground.
- Now get the IR LED and connect it's Anode/+ve terminal to +5v and Cathode/-ve terminal to Ground via 100/150ohm resistor. This will act as the transmitter.
- Now connect the second IR LED in reverse bias. Connect its Cathode/-ve terminal to +5v and connect it's Anode/+ve terminal to Ground via 15k ohm resistor. This will act as the reciver. (you can use a photodiode if you have one)
- Once the receiver IR LED is connectedconnect a wire from pin no.3 of the IC and Anode of the receiver IR LED.
With this, the connections are done and the circuit is ready to be powered up by a 6v battery.
When you power up the circuit the LED would be off but as you take your hand over the IR LEDs the normal indicator LED should glow.
If it doesn't then recheck all your connections and try again.Where to Use ?
sThe ensor can be used for many projects.once completed and tested you can solder it to a PCB and make a small module like the ones sold online.
It can be used for obstacle avoidance robot or line follower robot. Or even for applications like motion detection, etc.
I have made it for a line follower robot and will be posting its tutorial, too.
Hope this was useful and informative.If you have any questions feel free to ask.