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.
Step 1: 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 is used to find a obstacles . 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 Instructable I'm going to show you how to make a simple IR Proximity module which will cost about ₹50-60
or about $1.
Step 2: Components Needed.
2. Two 100ohm resistors.
3. One 15k ohm resistor.
(any value between 100-150 ohm will work and any value between 10-15k ohm will also work)
4. Two IR LEDs.
(One IR LED and one Photodiode can also be used but as I found it difficult to get my hands on a Photodiode I used IR LED instade)
check these LED & Sensors which you can use.
5. Two white LEDs.
6. Breadboard wires.
8. 10k ohm variable resistor (Optional)
These parts are easily available in any electronics shop and are very cheap or you can buy it online from Amazon or Ebay. or you can refer to the links I have provided
Once all components are gathered we can move to the next step...
Step 3: Making Connections.
Follow the circuit diagram and make the connections, refer to the pic 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 white 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.
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.
Once the receiver IR LED is connected
connect 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 white LED should glow.
If it doesn't then recheck all your connections and try again.
Step 4: Uses.
The Sensor 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 linefollower robot and will be posting it's tutorial too.
Hope this was useful and informative.
If you have any questions feel free to ask.