IR Proximity Sensor.

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.

1. LM358 IC
   Link for US
   Link for Europe
2. Two 100ohm resistors.
   Link for US
   Link for Europe
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 instead) check these LED & Sensors which you can use.
   Link for US
   Link for Europe
5. Two white LEDs.
   Link for US
   Link for Europe
6. Breadboard.
   Link for US
   Link for Europe
7. 10k ohm variable resistor (Optional)

These parts are available at UTsource.net

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.

Thank you...

Comments

[tkle2]

What circuit elements are Rx and Tx refering to?

[Harsh Dethe]

Receiver and transmitter, the IR LED in forward bias is transmitter (Tx) and the one in reverse bias is receiver (Rx)

[saim68]

How did u find those particular resistance values range??

[Harsh Dethe]

Colour code.

[jimMaskell]

Are the values of the resistors very important? I only have acces to 220R, 100k and 1k resistors.

[Harsh Dethe]

Yes values of resistors is important. Because different resistors will change the intensity and sensitivity of the sensor

[saim68]

How did u know those were the perfect resistor values

[JohnW51]

Where can I buy a circuit board like the one shown in this project?

[Harsh Dethe]

All the links are provided in the articles.

[saoudsindhi]

how IR sensor use for distance measure.?

[Harsh Dethe]

IR LED emits light which is reflected from a surface in front of it, The reflected light is sensed by an IR receiver or photodiode. Measuring the intensity of the light reflected back, You can write an algorithm to measure distance.

[LaszloS42]

Hi I just assembled this on a breadboard and the led is always on, added a resistor to it but it still stays on, is there anything else i may have missed because it is hooked up exactly as yours is.

[Harsh Dethe]

if you have made it as in the diagram with same components I've used then you must try switching the receiver LED around. I would suggest first use your cellphone camera to check the LEDs the transmitter one should light up and the receiver one shouldn't.

[MukulB8]

can you please make one on PCB

[Harsh Dethe]

It is not very difficult once you make it work on Breadboard. I'll try to write an Instructable on how to design circuit on PCB .

[MukulB8]

can i use tv sensor istead of photodiode?

[Harsh Dethe]

you mean IR transistor? if so you'll need a little different set up. using 2 IR LEDs is much more easy and cheap

[MukulB8]

ok thanks i try to make with two IR leds

[jayparale08]

When i connect the circuit to supply my led is on plz help where i am wrong

[Harsh Dethe]

add a 220ohm resistor in series with the led