IRForum

Hi, I've been trying to play around with different IR LEDs to flood a room(approx 20-30 sqm) with IR in order to control multiple moving targets at the same time (20+) i'm having some trouble achieving the range i need and flooding at the same time. It seems a narrow beam helps with more range but you sacrifice area of effect and wide beam seems to sacrifice range. I cant seem to figure out the sweet spot. I played around with two TSAL 6400s pulsing 300 ma using the constant current circuit on this forum but i only seem to get around 8m out of that and i have to point fairly accurately the farther i go at my device.
I've ordered this higher power LED to play with but have not yet:


My question is am i better off possibly mounting multiple narrower beam lower power LEDs like a Tsal 6400 on one transmitter in an arc? Or 1 or 2 much higher power LEDs with a wide angle and driving it with 1.5A? I am willing to place multiple transmitters in 2-4 corners of the room to achieve this but im not sure what the best course of action is. Ive read that IR can bounce fairly well so i feel this should be achievable. My room will be dimly lit and no ambient light will be involved.

As a first step I would try 2 different LEDs with different angles.

If that does not work, try multiple pairs of LEDs to give more coverage.

If that does not work...using a 12V supply only to the first LED, would allow many more IR LEDs to be connected in series.

Please provide more detail about what you are trying to control & the speed of the targets.

What IR receivers are you using?

Also, consider having more than 1 receiver on each target to capture different angles to the target..

Have you considered a ceiling mount for the emitter?

Thanks for the suggestions I will try different LEDs. What do you mean a 12V supply ONLY to the first LED?

Im trying to control wearable devices the targets are just people moving normally. No fast targets.

I'm using a standard IR receiver i had lying around not sure the part number, i didnt think the receiver makes that much of a difference. Should I look for certains specs?

I have considered a ceiling mount but I thought that might be more difficult to work with. Would i mount numerous LEDs in a circle perhaps?

What do you mean a 12V supply ONLY to the first LED?

In the circuit mentioned where the 5V connects to the first LED...if you connect it to 12V instead, you can put up to 6 IR LEDs in series. The rest of your circuit can be 5V or 3V£ levels.

Alternatively, our SendIR module (via our webshop) comes with 2 IR LEDs in series delivering over 300mA to each LED. You could hook several of these up together by daisy-chaining the Tx signal.

Im trying to control wearable devices the targets are just people moving normally. No fast targets.

However, they will likely block each other from time to time. So having more than 1 receiver on each target could help. (Or just one on the head with a ceiling emitter.

i didn't think the receiver makes that much of a difference

...famous last words....it matters a lot! Particularly in your use case.

I would need to know more about signals you are sending, how often and the frequency etc.....details

I have considered a ceiling mount but I thought that might be more difficult to work with. Would i mount numerous LEDs in a circle perhaps?

For what you described...it would likely be better.

For use cases like these there can be better/alternative solutions to the one you are using. Would need more details.....etc

In the circuit mentioned where the 5V connects to the first LED...if you connect it to 12V instead, you can put up to 6 IR LEDs in series. The rest of your circuit can be 5V or 3V£ levels.

Right thats what i thought

However, they will likely block each other from time to time. So having more than 1 receiver on each target could help. (Or just one on the head with a ceiling emitter.

Occasional blocking is not an issue

...famous last words....it matters a lot! Particularly in your use case.

Oh no what should i be looking at when it comes to receivers? Sensitivy?

I would need to know more about signals you are sending, how often and the frequency etc.....details

I would be sending signals sporadically sometimes a 2-3 a second other times once every few minutes.

For use cases like these there can be better/alternative solutions to the one you are using. Would need more details.....etc

What do you suggest? What kind of details are you looking for?

If you post the type of signal you are sending (protocol, #s bits & carrier frequency) I can suggest a good receiver.

If you post a reasonable textual summary of the use case of your project, I may be able to make some helpful suggestions.

I'm still in the testing phase so i have not decided what the ideal protocol and carrier frequency should be and to be honest im still learning the differences. But im currently just using the basic 38Khz frequency and NEC protocol. My project basically involves controlling LEDs for the most part.

Ok

So a good IR receiver would be TSOP34438. This along with the suggestions above should be OK.

When using NEC, if you can use less than the standard 32 bits...say 24 or 16 bits then the performance should be better.

you only need 24 bits for full RGB coverage (vs 32 for NEC standard)


In most situations you shouldn't need the full RGB spectrum..so using 6 or 7 bits per colour could suffice.(=21 or 18 bits)

Will definitely try that receiver thank you.
I went ahead and mounted 6 TSAL 6400s together and thats working much better. According to the datasheet its supposed to withstand upto 1.5A pulsed
Would pulsing 1A through the LEDs help achieve maximal range? Do you think the LEDs can handle that?

When using NEC, if you can use less than the standard 32 bits...say 24 or 16 bits then the performance should be better.

Will keep this in mind.

The strongest TV remotes can use around 300mA. So I tend to stick with that as an upper limit/range.

The datasheet does cover the upper limits for LED current. However, I would suggest you give serious consideration to safety and assume that people will walk up to the emitter and look directly into it.

Unfortunately, I am not in a position to provide any advice or suggestions wrt safety issues like this. There are standards available but you must do your own research & validation.

I suspect your best approach is to come up with a solution that works without maxing out the IR current. (e.g. emitter on ceiling or high on walls, multiple receivers per person, a mix of TSAL6100/6200/6400s)