long range -Remote signal strength length increment

hi friends!,

Normally the IR led transmit the signal and we get the output from the receiver.Many circuits are in the google search engine. But i want the remote work in the long range distance. maximum 35 feet.Is it possible?.

I checked with my TV remote . The remote manufacturer used the transistor based circuit. I tried with the NPN 2n2222 transistor. (i used 160 ma in Ic)its work in the range of 20 feet only. The maximum forward current of my IR led is 100mA. How to make the circuit with working in the long range upto 35 feet ? How to increase the length of successful transmission? i am using the 38 KHz carrier frequency IR wave. the wavelength 940n.

i attached the circuit below.The r1 is 2.7K and the R2 is 47ohm 2 numbers connected in parallel. i tried it , it works on some 20 feet distance only.

Suggest your design ideas.

thanks for your future help. Please provide details whatever you have.

You are doing very well to make a homemade remote control that works from 20 feet away.

I do not know what is a safe current burst to send through an IR led. You probably would like to increase it, but 100 mA sounds about like the safe limit for one LED (unless the datasheet says otherwise).

To get greater distance, you'll need to add more sending LED's. Either in series or parallel.
If in series then you may need to increase the supply voltage.
If in parallel then you need to add balancing resistors so one led does not 'hog' the current.

If you want to experiment, fit a reflective tube in front of the IR led so it will aim a concentrated IR beam toward the detector.

BradtheRad said:

You are doing very well to make a homemade remote control that works from 20 feet away.

I do not know what is a safe current burst to send through an IR led. You probably would like to increase it, but 100 mA sounds about like the safe limit for one LED (unless the datasheet says otherwise).

To get greater distance, you'll need to add more sending LED's. Either in series or parallel.
If in series then you may need to increase the supply voltage.
If in parallel then you need to add balancing resistors so one led does not 'hog' the current.

If you want to experiment, fit a reflective tube in front of the IR led so it will aim a concentrated IR beam toward the detector.

Click to expand...

Thanks for your reply.
The Peak forward current of the IR led 1A. So that is not the problem. because we gave the pulsed voltage to the LED. Absolute maximum of forward current is 100 mA. my question was how to increase the strength and make the long range sensibility. if additionally we add the paralleled same led ,how the current not flow to that particular LED? Is it increase the length distance of range ? do you know any IR LED have the highest current?

Once again thanks :grin:

Instead of pumping more power to waste, try to use a larger optical reflector to direct better your light into the receiver.
Use a flashlight reflector, e.g. 2-3 inches in diameter, to see an extended range.
Naturally you must point your beam on the spot. For this you can add a laser pointer and align its axis with your device.

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And you can use another such reflector in the receiver.
More courageous can adopt an IR laser as light source (modulated like the LED). But such device may be dangerous to human eyes. I would prefer the reflectors, it is cheap and it worked for me for over 100 m.