need of long range IR transmiter

[compass1982]

hello everyone,
can anyone show me how to biuld a long range IR transmitter circuit (can be detected more than 20 centimetres from a IR detector). and any suggestion on the IR transmitter led? please help, i am stucked in he middle of my project

 

[HarveyH42]

We really need a lot more information. Can you post a diagram of what you've done so far? How much more than 20 cm? A TV remote is good for 15-20 feet. The IR laser diode from your slow-ass 4X CD burner might get you half a mile (and possiably do some permanent eye damage...).

Most IR LEDs put out plenty of light, just that it's not reflected well. Instead of potential eye damage, it would be better to work on the detection/reciever side.

 

[audioguru]

If you are transmitting data, not voice or music, then why not use the simple IR transmitter circuit in a TV remote and a TSOP IR receiver IC? They have a range of about 10m.

 

[Nigel Goodwin]

If you are transmitting data, not voice or music, then why not use the simple IR transmitter circuit in a TV remote and a TSOP IR receiver IC? They have a range of about 10m.

Easily that, when I was testing my IR PIC tutorial circuits they worked fine the full length of the workshop at work, something like 18 metres?.

 

[compass1982]

this is the IR transmitter and receiver that i constructed:

If you are transmitting data, not voice or music, then why not use the simple IR transmitter circuit in a TV remote and a TSOP IR receiver IC? They have a range of about 10m.

i am not transmitting data too, juz wanted to use the transmitter IR light to activate the receiver circuit. i found that this TSOP is good, can please provide the full circuit for me? thanks a lot

 

[audioguru]

You don't have a current-limiting resistor in series with your IR LED. It will burn.

The TSOP1738 is a complete IR receiver. It needs only a 5V power supply. Get its datasheet from www.datasheetarchive.com .
Nigel also has them in his PIC tutorials.

 

[compass1982]

i have a question, based on the circuit that i constructed, is it possible to boost it so that the transmitting range becomes further?

 

[audioguru]

i have a question, based on the circuit that i constructed, is it possible to boost it so that the transmitting range becomes further?

Of course. Use a TSOP IR receiver IC for very long range. Your IR receiver circuit is just a single emitter follower transistor with hardly has any gain.

 

[compass1982]

are you saying that the problem that caused my IR circuit could not work in long range is because of my receiver circuit? so u suggest i replace the normal IR detector with TSOP into the circuit or only plug the IR to the PIC? sorry to bother as i am a noob in electronic stuff.


edited: is the TSOP compatible with other ordinary 2 pin IR transmitter ?

 

[audioguru]

Yes, your receiver didn't have any gain. A TSOP receiver has lots of gain and many other features.
The TSOP is tuned to an IR carrier frequency. The TSOP1736 is tuned to 36kHz, the TSOP1738 is tuned to 38kHz and there are also other carrier frequencies available. Just tune the frequency of your 555 oscillator in your transmitter to the same matching frequency.

 

[compass1982]

thanks for the reply. TSOP 1738 is being tuned to 38kHz, meaning i must tune my 555 timer exactly 38kHz or is there any tolerance? can u show me the formula to tuned the 555 timer, as i wanted to compare with my formula. thank you

 

[audioguru]

The datasheet for the TSOP IR receiver shows the width and tolerance of its bandpass, and the datasheet for the 555 shows the formula for its frequency.

I think the resistor values in your 555 oscillator are too low, and the capacitor's value is too high.
You should add a current-limiting resistor in series with the IR LED so that its current does not exceed the max spec'd on its datasheet.

 

[compass1982]

i have reconstructed the circuit, is the value of the resistors and the capacitor ok for this circuit?

 

[philba]

your LED doesn't have a current limiting resistor. (hmm, seems like I've heard that before...). it's hard to say which will burn out first - the 555 or the LED. also, you left rst floating, no cap between con and gnd and no decoupling caps. other than that, it's fine.

look here for more info: **broken link removed**

 

[compass1982]

regarding the TSOP1738, is it the receiver itself already capable to boost the range of 20 metres? or it need additional circuit to make this happen? can anyone show me the programming for this sensor? i am using PIC 16F877A? is the output of TSOP1738 measured by resistance or voltage?

 

[Nigel Goodwin]

regarding the TSOP1738, is it the receiver itself already capable to boost the range of 20 metres? or it need additional circuit to make this happen? can anyone show me the programming for this sensor? i am using PIC 16F877A? is the output of TSOP1738 measured by resistance or voltage?

It's just a standard logic level output, you can connect it directly to an I/O pin on the PIC - check my tutorials for exact details - it's ESSENTIAL to include the decoupling capacitor and resistor in the power feed to the receiver, or you get seriously strange problems!. There's no programming involved with the sensor, only of the data you send over it.

You can't really do anything to the receive side to increase range, you need to increase the transmit power - multiple LED's, higher power pulses, more accurately focused (using narrower beamwidth LED's).

 

[compass1982]

thanks, i do get to your tutorials site (but yet i still could not find any details about the sensor, can you show me the direct link?) and i found that the coding that you used is different from mine. i am using microcode studio plus to write and compile my program. winpic800 to burn my program into the PIC.

 

[Nigel Goodwin]

Try

 

[panadol]

hi, sorry to interrupt.
im also building something like what mr.compass is building...

my problem is that my range of IR is very very short, i would say it is only about 5cm..my IR led is being supplied for 100mA(which is the max)

I am using normal IR transmitter and normal receiver.
As i've read this thread, im quite consufed over what actually does affect the range of the IR beam?
isiit the receiver?transmitter?

I am getting a TSOP1738 soon and i havent try on it yet. will this recevier actually boost my detection range?

I thought of getting a highpower wide beam IR emitter too....my desired range is around 15~20 feets.

 

[Nigel Goodwin]

Both affect it, you can pulse the IR LED at fairly high currents (1A is quite common), and this increases the range. Using the TSOP receivers is good as well, as these are very sensitive and a really easy to use - bear in mind you need to modulate your LED at 38KHz or so, depending on the exact TSOP you use.