IR Detector





Introduction: IR Detector

In this Instructable I will show you how to make a simple infra red (IR) detector.
When your TV stops responding to the remote it is hard to tell if the TV is broken or the remote doesn't work. With this little pocket-sized gadget you will know.
Spying has become more and more accessible to the average man. Whit this gadget you can check if someone has installed a night-vision camera in you room or office.

First I am going to show you how to build it and then how to use it.

If you are just interested how IR remote control works got to step 7.

Step 1: Electronic Components

For this project you will need a couple of electronic components,all in total 3$.

1. Fototransistor (IR_Transistor);( in this chase I used RadioShack 276-0145);(picture 2)


3.Micro switch.

4.330 Ohm resistor (picture 3)

5.An electronic solder board (holes)

6. 9V battery snap

7. 9V battery

8. Rubber band

(all of the electronic components can be bought at your local RadioShack)

Step 2: Tools

You aren't going to need many tools for this project.

1.Wire cutter

2.Wire insulation stripper

3.Heavy duty cutter or a big wire cutter ( to cut the board)



6. Soldering iron (not shown)

Step 3: Mark and Cut

Use the marker and draw the line that you will cut. Mine is 7x2.5 cm. Just enough space to fit the battery and the circuit.

Step 4: The Schematic

OK, first I will give you the schematic and then I will explain it.

Step 5: Put It All Togother

First take the Fototransistor,bend it (picture 1) and solder it. (picture 2)
Now take the LED and solder ti. (picture 3)
Take the resistor and connect the negative(shorter) pin of the fototransistor and the positive(longer) pin of the LED whit the 330 Ohm resistor,(picture 4) and cut the pins.(picture 5)
Solder the switch in between, a little bit down.
Now take the 9V battery clip and cut it about the lenght so that you can connect it to the switch and the fototransistor. Save the black wire from the battery clip because you are going to need it.(picture 6)
Connect the black wire from the clip to the switch, and the black wire that you saved, from the switch to the negative(shorter) side of the LED.(picture 7)
Connect the red wire to the remaining pin,the positive(longer) side of the fototransistor.(picture 8)

Step 6: You Are Done

Now, just connect the battery clip to the 9V battery and secure it to the board whit a rubber band.

Step 7: Remote Control by IR Signals

Infrared Remote Controls: Inside
The dominant remote-control technology in home-theater applications is infrared (IR). Infrared light is also known as plain-old "heat." The basic premise at work in an IR remote control is the use of light to carry signals between a remote control and the device it's directing. Infrared light is in the invisible portion of the electromagnetic spectrum.

An IR remote control (the transmitter) sends out pulses of infrared light that represent specific binary codes. These binary codes correspond to commands, such as Power On/Off and Volume Up. The IR receiver in the TV, stereo or other device decodes the pulses of light into the binary data (ones and zeroes) that the device's microprocessor can understand. The microprocessor then carries out the corresponding command.
To get a better idea of how the process works, let's take a look inside a typical remote control -- the universal remote that came with the author's digital cable box. The basic parts involved in sending an IR signal include:
-Integrated circuit
-Button contacts
-Infra red light-emitting diode (IR LED)

On the component side, the infrared receiver sits on the front of the device where it can easily see the signal coming from the remote control.
You've probably noticed that some remotes only work when you're pointing them directly at the receiver on the controlled device, while others work when you're pointing them in the general vicinity of the receiver. This has to do with the strength of the transmitting IR LED. A remote with more than one IR LED and/or a particularly powerful IR LED produces a stronger, broader signal.

Step 8: Test Your Creation

You are all done!!! Test you creation!

Take any remote. Put you fototransistor close to the IR LED of the remote. Push the switch,hold it, and push any button on the TV remote,hold it. The LED on the detector should start blinking.

IR light is not visible by a naked eye but you can see it whit a camera also! (picture 3)

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Please be positive and constructive.




Thanks for the instructable, very simple and quite informative. Could I adopt this type of sensor into a laser tag system? Maybe run a line of them over a vest and have them react when either one is hit? If anybody out there could help me out with this, please.

You can also use your phone's camera to detect IR.

instead of using fototransistor i can use photodiode

I have been trying to make this on a bread board before soldering it and the LED lights up and stays on. Any reason why it would do that?

This might be because the detector is detecting the infrared light that is being emitted by the lights in your room. If you cover the tip of the detector with your finger or turn the lights on, does the LED still glow?

There are 3 different types of Photo sensitive Devices and they can look almost identical. I have bought plenty off E Bay and from sellers here and in China claiming they are such, but are in fact much cheaper less useful IR Photoresistors (LDR's) Black or clear in the same 3mm or 5mm package these make Nil output exposed to light, their Resistance just drops like in conell1 project I suspect. You need a proper Photo Transistor like the one listed, or similar like the Kingsbright L-93DP3C

but it is very weak :(
tnx anyway it was fun to learn :)


can we increase its range

can we use a ir led of a remote in place of fototransistor.

our body also releases heat so can we make a circuit to detect it .