Hello all,
I have one of the small Chinese amplifiers with dreadful remote reception. I'm pretty sure this is due to the IR eye, I believe it is a "IR receiver module" from my research, being about 3mm behind the opening on the front metal panel of the amp and the hole is ~3mm. The sensor cannot be pushed forward as it is mounted all the way to the surface of the board.

I tried placing ~4mm piece of cylindrical clear plastic into the opening on the front, like a lens, in an attempt to sort of reflect the remote signal into the hole. After a bit more research, I believe the 'lens' would need to be red for it to have a chance of working.

Am I even close to a potential solution?

Thanks for reading!

 

Hi Brian
Do you have a module type/number for your Chinese IR amp.?

You don't need a Red lens for focussing.
Usually an IR filter is to reduce the ambient light falling on the sensor, which can effect the performance.

What is the project controlling.?
E

 

Welcome to AAC.

You are unlikely to have any success with a light pipe that doesn’t have a larger aperture than the 3mm hole.

A much better approach would be an IR Repeater like this one. It just “watches” for the IR signals then repeats them to the IR LEDs attached to it. While I couldn’t find a good selection on Amazon, there are version that use small, flat, right angle housings for the LEDs intended to be attached directly to the device being controlled over its IR receiver aperture. The one in the link has several transmitter LEDs to cover the inside of a cabinet, which allows it to be closed and still work with the remotes for whatever is in there. It is USB powered but is a completely standalone device that needs no configuration.

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I am struck by the Aussie pricing and lack of selection. I know the AUD is only .67 USD but the prices are still insane. The device below is exactly what I would hope you could find and it is ~$10USD on Amazon in the US. The model above is not available in the US so I can’t compare but it would probably be no more than $15USD.

​

 

Hi Brian
Do you have a module type/number for your Chinese IR amp.?

You don't need a Red lens for focussing.
Usually an IR filter is to reduce the ambient light falling on the sensor, which can effect the performance.

What is the project controlling.?
E

Thanks for the quick reply!

I will have to open it up tomorrow and see if there is any info. I can at least share a photo of it.

You are unlikely to have any success with a light pipe that doesn’t have a larger aperture than the 3mm hole.

A much better approach would be an IR Repeater like this one.

Thank you for the input.

I am familiar with such devices but there has to be a much simpler solution. The front of the amp is directly in front of me, ~ 2.5m away, on a shelf without anything in front of it just under the TV.

So if I find a light pipe >3mm diameter I may have success? Maybe like a mushroom shape?

 

Hi Brian
Do you have a module type/number for your Chinese IR amp.?

You don't need a Red lens for focussing.
Usually an IR filter is to reduce the ambient light falling on the sensor, which can effect the performance.

What is the project controlling.?
E

For something to act as a light pipe in any useful way it has to be capable of multi-mode transmission at the desired frequency. I can’t find a single example of a light pipe made of plastic intended for IR use. There are metallic ones that are basically inside plated tubes, kind of neat but not relevant.

Common polymers like PMMA (Plexiglass, Perspex), and PC (Polycarbonate, Lexan) are very good at transmitting IR in the proper range for IR remotes (~850nm) but I don’t know if they exhibit TIR (Total Internal Reflection) at that wavelength that would allow them to act as effective light pipes.

And, we are still dealing with a tiny aperture so the input to the potential pipe is very limited so losses are material and light pipes are not particularly efficient when the source is off center.

I believe the best solution is either relocating the internal IR sensor by moving it closer to the panel, or making it entirely remote. This is major surgery, so the proxy version that I suggested seems the best route.

 

Hi Brian,
Anyone of these lens options usable for your project.?
E
https://www.google.com/search?clien...HcqmCtQQjJkEegQIChAC&biw=1117&bih=634&dpr=1.4

 

So if I find a light pipe >3mm diameter I may have success? Maybe like a mushroom shape?

I think the light pipe is a non-starter, but theoretically you could possibly use a lens outside to maximize off axis transmission to the inside. Alternatively, you could increase the size of the aperture? You could replace it with a piece of PMMA intended for IR use. You can get very dark red, and even black.

 

Hi Brian,
Anyone of these lens options usable for your project.?
E

This particular lens might work. You’d have to remove the flange on the back but that shouldn’t be too hard. I think I would consider the 45° version rather than wider—or the narrowest that covers where you will be using it from.

I think its quite speculative, though, and while the experiment might be worthwhile, I would give it a low probability of success.

 

Maybe the problem is in the remote controller. Is the transmitting IR LED aligned properly and does it have a clear path? Is the IR filter on it clean and free of scratches. Do you have a known good battery in it and are the battery contacts clean?

 

Wow! This is much more complex than I anticipated... As is usually the case when it's not one's profession.

I just tested the 3 battery and it is 3V. It and the contacts are clean, I see no scratches. I also checked and verified the remote is sending a signal with my phone. The effectiveness of the remote has been poor since new.

I certainly don't need 200 lens so I'm happy to try several other ideas. Of which, couldn't I simply disassemble and use the lens from another IR receiver module?

 

Just realised I never replied with an update. After closer inspection I noticed the IR sensor was ~4mm further from panel than the other 3 LEDs and leaning to one side.



In addition, On the inside of the front panel are ~2mm recesses that added further distance from the opening.



I re-soldered it seated correctly, bent it forward and that significantly improved reception.

Thanks again for assisting!