Selection for IR Emitter & Receiver

[attabros]

Hi everyone,

I'm going to start a project "Infrared Data transfer"
therefore I'm little confused about what devices should I use
as IR transmitter & IR receiver the devices should support
the range between 30 to 45 meters.

Can anyone suggest how I will chose IR transmitter &
receiver as well as necessary notes to start this project
as I haven't done this type of communication before.

Thanks.

[FvM]

Hello,

30 to 45 m is quite a lot and will need a powerful sender and/or good optics. As you didn't specify your data transmission requirements further, I can't give particular hints. For low speed transmission, usual remote control receivers can be a solution. PIC projects with software generated modulation for this kind of receivers can be found everywhere at the internet. The use either RC5 remote control or selfmade protocols.

Regards,
Frank

[attabros]

Does the range depend on Receiver device or transmitter or both
transmitter & receiver depends on it ? I saw some projects
on the internet they use a simple IR led for transmitter
& on receiver side there is a three pin (GND VCC & output) IR receiver device.

[FvM]

For a given protocol, modulation type and transmission bandwidth, the range mostly depends on the sender but also on the receiver, unless it's operating noise limited (= at the physical defined sensitivity level).

In a practical view, you seem to lookout for existing receiver solutions as the said three-pin remote control ICs. I've been talking of software generated modulation and that's just another word for using a simple IR LED respectively more than one together with an appropriate high current driver. As a simple calculation, if you achieve e. g. 10 m range with a single IR LED (probably not when driving it from a PIC pin without current amplification), then you need an array of about 20 for 45 m with an identical receiver.

I suggest, to review the said internet projects more thoroughly.

[SherpaDoug]

The optics can play an important part if you can use directionality. Can you point the transmitter and receiver at each other? How accurately can this be done? The narrower the beam of the transmitter and the field of view of the receiver the longer range you can get. This can be hard to do if either end is mobile.

Also two low power transmitter LEDs may be more reliable than one high power if there might be a small obstruction like a blade of grass.
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The search for better is endless. Instead simply find very good and get the job done.

[Rohit de Sa]

For low speed unidirectional communication I have achieved excellent results with a cheap Sony-type remote control. The Sony-type remotes use the SIRC protocol. With a simple TSOP1738 and a 12F675 on the receiver side I got a range of over 15m in noon sunlight, and over 30m at night with streetlights. You may try this out as well, but naturally your results may vary. Do note that the flicker from fluorescent lighting sometimes creates problems with IR. A filter may be of use.

FvM said:

[temtronic]

As others have said , 'optics' will be the main issue.

I'd startout using one of those super cheap LED laser pointers or a 'laser level' that you can SEE. They can cover the distance allowing you to cut code and get the optics 'right', then switch over to the IR devices.

This way you'll not be fighting 'is it my code, or the optics or the IR devices or the 'world' that's making life miserable'...
Small clean steps are always better than jumping into a mudhole!

[Gabriel]

you could consider modulating a cheap red laser pointer..
and using a standard ir demodulator IC.... they come in diferent modulation frequencies and output straight TTL level digital signals...

.... your range would be.... well as far as you can acurately aim your laser i would say.... 30 - 40 m easy.

just a thought...
_________________
CCS PCM 5.078 & CCS PCH 5.093

[languer]

2+ year old topic guys

[Gabriel]

you are right.... didnt even notice... sorry.
_________________
CCS PCM 5.078 & CCS PCH 5.093