need help to build long range IR transmitter

[aruna1]

hey guys I'm trying to build a 38khz transmitter that works about 5m(at least) but its unsuccessful.currently I'm using this circuit. but it cant use more than 50cm. i have no idea how to increase rage.

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equation is f=1/(0.8*R1*C1)
I have some NE555 and a 9V battery some transistors and couple of 0.1uf,0.01uf caps.can some one give me a circuit with higher range (at least 5m).
i know i have to give large current to IR led but i cant figure out a way to do that.

and i want some thing that will not eat 9v battery.
thanks

 

[Mikebits]

The value of R2 seems a bit large. I think your transistor is not turning on enough due to R2. Also R4 and d2 are just wasting current and are not needed.

I assume U1 is getting power as it is not shown.

 

[aruna1]

R2 and D1 is for indication.
and can you suggest a value for R2?

 

[Mikebits]

R2 and D1 is for indication.
and can you suggest a value for R2?

You really don't need an indication, it is just bling. I have not looked at data sheet for your transistor but I would guess maybe a 1k or less resistor for R2.

You can experiment by dropping the value and see if range improves.

 

[Mr RB]

After fixing R2, reduce the duty cycle by putting a diode and resistor (in series) both in parallel with R1. That will give a shorter LED on cycle. I would try for an on duty of maybe 10%. Then after you tune the frequency back to the sweet spot you can increase LED on current by reducing R3.

 

[aruna1]

You really don't need an indication, it is just bling. I have not looked at data sheet for your transistor but I would guess maybe a 1k or less resistor for R2.

You can experiment by dropping the value and see if range improves.

i'll chk,thanks

 

[xtrmi]

What is the maximum distance for an IR transmitter? I was thinking of a similar project.

 

[blueroomelectronics]

What is the maximum distance for an IR transmitter? I was thinking of a similar project.

What range do you need?

 

[xtrmi]

Lets say 300 feet? I actually only need about 30 feet, but can 300 be achieved?

 

[blueroomelectronics]

30ft yes (indoor), 300ft not really. Use RF for 100m range like an XBee.

 

[aruna1]

What is the maximum distance for an IR transmitter? I was thinking of a similar project.

i guess reciver support upto 10m

 

[Nigel Goodwin]

R3 is massively too big it wants to be at least only 10% of that, and preferably smaller - you really need 1A or so pulses through the IR LED.

You also don't want to feed it with continuous pulses, short bursts of pulses generated from a PIC are far better, and give a much longer range.

Check my IR PIC tutorial, it uses very few parts, and does 15m easily, as most IR remotes do.

 

[aruna1]

Finally finished(i guess)

R3 is massively too big it wants to be at least only 10% of that, and preferably smaller - you really need 1A or so pulses through the IR LED.

You also don't want to feed it with continuous pulses, short bursts of pulses generated from a PIC are far better, and give a much longer range.

Check my IR PIC tutorial, it uses very few parts, and does 15m easily, as most IR remotes do.

well i was thinking using a pic for simple transmitter is a waste coz PICs are expensive here.
anyway i found a 555 circuit and it seems working (didn't had time to chk distance).
that means my project(remote fan controller) is finished.i used 12F675 in receiver and code is using 99% memory,so i had to remove few options).i probably i will be able to upload all details (description schematic source code etc, ) if i can finish documenting.(i guess there is a separate forum or something here to post projects)

thanks everyone for all of your help.

 

[blueroomelectronics]

You might be better off to use a regular TV remote control as the transmitter, they output data in pulse streams (your IR detector probably won't like continous IR)

 

[Nigel Goodwin]

You might be better off to use a regular TV remote control as the transmitter, they output data in pulse streams (your IR detector probably won't like continous IR)

No, assuming it's a TSOP type, a continuous wave will drastically reduce range.

 

[blueroomelectronics]

That's why I said to use a TV remote. It's pulsed and cheap. Nice case & lots O buttons too.

 

[aruna1]

i finished my project
thanks for everyone who helped me

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