IR sensors

[arien]

hi everyone..

we are currently doing a project on our electronic design subject. it is an automated light control system and we are using IR sensors for that. The project is working but the problem is that the range is too small. The transmitter and receiver works when they were 5cm apart only. can anyone recommend a long range(approx. 3 feet or more) pair of IR sensor with low biasing voltage? (9V) Please give the specific specs if you can. It will surely help us. Thanks a lot and God bless.


arien

 

[audioguru]

Why not fix the circuit that you have?
Attach its schematic and parts list for us to see why its range is so small.

The range for most TV IR remote controls is 10m.

 

[Krumlink]

They have such crazy range because they are blasted with around 1 amp of current so fast that it doesnt effect the LED much.

 

[audioguru]

TV remotes use an IR receiver IC that has high gain. Its case rejects visible light. It has automatic gain control. It has a bandpass filter. It is smart.

 

[penoy_balut]

TV remotes use an IR receiver IC that has high gain. Its case rejects visible light. It has automatic gain control. It has a bandpass filter. It is smart.

Agree.

I use TV IR TX/RX LEDs for my projects they are cheap, low power and long range. Data modulate the 38kHz driving IR transmitter, make your own communications protocol or use the popular RC5.

 

[arien]

hello..

Why not fix the circuit that you have?
Attach its schematic and parts list for us to see why its range is so small.

The range for most TV IR remote controls is 10m.

attached here is the transmitter and receiver we have used.. the parts and components used were indicated.. please kindly check the circuit provided..
thanks a lot..

 

[audioguru]

The receiver doen't have an amplifier for the extremely weak signals from the IR diodes. The IR diodes are probably sensitive to visible light unless they have a black case.
No wonder the sensitivity is poor.

 

[philba]

agreed. use a modulated IR receiver like the 1138 from vishay (or similar). You will need to modulate the transmitter so it will require a second 555.

 

[arien]

agreed. use a modulated IR receiver like the 1138 from vishay (or similar). You will need to modulate the transmitter so it will require a second 555.

How can we modulate the transmitter? How can we incorporate that to the present tx circuit? thanks a lot.

 

[arien]

I use TV IR TX/RX LEDs for my projects they are cheap, low power and long range. Data modulate the 38kHz driving IR transmitter, make your own communications protocol or use the popular RC5.

RC5?.. microprocessor?.. sir,we don't have enough knowledge on microcontrollers..