Infrared Extender

Hello all,

I'm just looking for a bit of advice before I start taking things apart.

I have a satellite receiver hidden away in a cupboard and I wanted to have a small infrared receiver at that tv so that I could change the channels without having the door open.

I thought that this would be cheap enough to buy until I started looking today, and they start at around £25.

So my question is whether or not it would be possible to just solder a few wires inside the satellite receiver to the existing points and run the cable up to a small IR receiver at the TV or would I need to repeat the signal along the way? It is only going to be 0.5m at the most.

I already have a infrared receiver connected to a 3.5mm jack which I took from an old video sender, so if it is possible to just simply connect this up I'll put a jack at the back of the satellite box and plug this in.

Thanks

The PICAXE IR commands only support the Sony protocol so you would not be able to use them direct with a satellite unit.
However, if you know (or can find out) what the protocol is for your unit, then it is very likely that you could bit bang the codes out.

That would then give you the possibility of using an existing remote to send to a PICAXE and relay anything (including sequences) to your satellite box.

It may be easier to use the output of an IR demodulator module to switch an oscillator (eg a 555) on or off to repeat the signal, though of course that's not as much fun as intelligently processing the signal.

If you're merely extending the leads to the receiver module by half a metre I imagine that would work fine, though.

I have had an IR "extender for about 10 years to control the TV and stereo in another room.

Very simple concept. No need to worry about signal protocol and no PICAXE needed .

1. An IR receiver photo transistor use to pick up the TV and Stereo remote controller signals in first room
(do not recall and not about to pull it apart, but there may be a simple transistor in the receiver box in room 1 to amplifier the electrical signal a bit)

2. The IR receiver photo transiitor sending the signal to the remote end via wire (some 6 or so metres in my case). 3 core stereo cable with 3.5mm plug each end (as ground, elect signal and +5V)


3. three IR diodes in series for signal strength to re-transmit the IR signal in the second room where the TV and stereo are lcoated.

Uses a ~6Vdc plagpack (wall wart) for a supply. No amplifiers. all very simple and works.

Did try with 2 lower power output IR diodes to start but not successful so advanced to 3 more powerful diodes in series and less series resistance.

Thanks for the quick replies, you must all be as bored as I am in work today!

I think I'll open up the box and try just running the cable first, if that doesn't work then I'll take westaust55's idea and try it that way. Hopefully with the distance being so short it won't be a problem.

Thanks again

IR extender

My daughter had one of these wireless devices that transmitted signals to a Sky box but the device did not actually connect to the Sky box instead what appeared to be a string of beads that came out of the unit was placed near the IR receiver on the Sky box and I presume the signal was IR and beads were some sort of fibre optic link. Might be an idea to simply use a fibre optic cable into the cupboard.

Just a thought don't know if it would work.

Richard

Tricky Dicky said:

My daughter had one of these wireless devices that transmitted signals to a Sky box but the device did not actually connect to the Sky box instead what appeared to be a string of beads that came out of the unit was placed near the IR receiver on the Sky box and I presume the signal was IR and beads were some sort of fibre optic link. Might be an idea to simply use a fibre optic cable into the cupboard.

Just a thought don't know if it would work.

Richard

Click to expand...

Could this have been some kind of filter to prevent other wavelengths affecting it?

Tricky beat me too it.

Optical fibre would be the simplest solution I think.

boriz said:

Tricky beat me too it.

Optical fibre would be the simplest solution I think.

Click to expand...

Could you explain this to me please.

Do you mean that I can just have a fibre optic cable running to inside the cupboard without having anything else attached?

I checked the cable that I have last night and it is an IR receiver connected to a 2.5mm jack. The thing is that there only seems to be two wires connected, I thought there had to be 3?

Think of fiber optic cable as a bendable "light pipe". Ideally, you would use an optical fiber that is rated for IR wavelengths.

You should get *some* IR transmission with almost any fiber cable, as most applications (broadband network connections, etc) don't use visible wavelengths.

See if you can find a UK supplier that has something similar to this (5 feet for $1.69US)
http://www.goldmine-elec-products.com/prodinfo.asp?number=G17059

John

I love this forum, I just find excuse after excuse to buy toys to play with.


If anyone would have a spare minute or two could you look at this link and tell me which would be the most appropriate for me to buy:

http://tinyurl.com/crfbxh

The 3rd link down, 1m of 1mm core plastic cable is only £2, would that do the trick?

I looked at the fibreopticfx.co.uk website but there are no prices, and I would guess they don't sell a couple of 2m anyway, though some of their pictures looked quite good.

@Cheesey
The £2 cable looks a good deal.
Get some to play with anyway.

But, you'll need other bits,
to interface to your TV system.
Others can advise.

e

eclectic said:

@Cheesey
The £2 cable looks a good deal.
Get some to play with anyway.

But, you'll need other bits,
to interface to your TV system.
Others can advise.

e

Click to expand...

That's what I was wondering. I didn't understand if I had to build a circuit that would receive the signal from the remote and then send it down the fibre optic cable or if it was just a case of pointing the remote at one end of the fibre cable and have the other end go inside the cupboard pointing at the satellite receiver.

Didn't want to sound like a total idiot by asking that though!

I have used the plastic fibre to extend the IR signals to a video recorder that was in another room. The run was I think about 4 metres.

John

modeng2000 said:

I have used the plastic fibre to extend the IR signals to a video recorder that was in another room. The run was I think about 4 metres.

John

Click to expand...

Could you explain how exactly you did it. What did you have at each end of the fibre?

I've just ordered myself 3m of it.

It’s the simplest solution because you don’t need anything at either end. Think of it like an elaborate system of mirrors that reflect the IR light from the remote to the receiver.

-Find the IR sensor on the front panel of your satellite receiver box.
-Fix one end of the fibre so that it ‘shines’ onto this sensor. Shine a torch into the other end of the fibre to help with alignment if needed.
-Pass the other end of the fibre through a hole and out of the cupboard and place near your TV with the end facing outwards (towards your chair)

IR light from your remote (pointed at the TV) will travel down the fibre and out the other end, inside the cupboard.

No electronics required.

boriz said:

It’s the simplest solution because you don’t need anything at either end. Think of it like an elaborate system of mirrors that reflect the IR light from the remote to the receiver.

-Find the IR sensor on the front panel of your satellite receiver box.
-Fix one end of the fibre so that it ‘shines’ onto this sensor. Shine a torch into the other end of the fibre to help with alignment if needed.
-Pass the other end of the fibre through a hole and out of the cupboard and place near your TV with the end facing outwards (towards your chair)

IR light from your remote (pointed at the TV) will travel down the fibre and out the other end, inside the cupboard.

No electronics required.

Click to expand...

Thanks for the explanation. I bought the 1mm core cable last night hoping that was the case.

I also ended up buying a 3m of 48 core cable too, I think I could easily entertain myself for a few days playing with that a a couple of leds.

I have another question about fibre and a laser, what are the generally rules for this forum as far as going off topic, I suppose I'd be better starting a new discussion in case anyone is searching in the future.

Thanks again

That is just how I did it except that at the output end I used an acrylic prism to turn the beam through 90 degrees so that I ddin't have the fibre sticking out from the front of the recorder.

John

Just wanted to say that the fibre arrived and everything is working perfectly. Job done for £2 and all I had to do was cut the cable.

thanks again for all the help

I think I posted too soon.

Yes the fibre optic cable is working but only if the remote control is close, the furthest away that it will work is about 18 inches.

So once again I'm asking for a bit of advice, how come it only works when I am up close? Could I put a prism or lens or something similar at the end of the cable to help?

I presume it only works if the transmitter is sending most of its light down the cable. Are the ends polished?

A

I haven't polished the ends of the cable, didn't know that I needed to do that. Does it make a big difference?

Everything works perfectly until I take the remote more than 18inches or so back, then it stops working.

Polishing will probably make a big difference. Like the difference between translucent and transparent. (See: http://en.wikipedia.org/wiki/Transparency_(optics) )

Also make sure that the fibre terminates as close as possible to the receiver sensor. Any light leaving the end of the fibre but not hitting the sensor, is wasted. A ballpark figure might be 90% wasted at 1 inch. You might need to cut a hole in the outer panel to get really close.

Also remember that the size of the other end (the light gathering end) is tiny compared to the total ‘spread’ of IR light coming from your handset. This will also have a large effect on sensitivity. A thicker fibre would help (or a bigger bundle). Another thing that might help is to cut the light gathering end at an angle, so that the end is oval rather than circular. This could double the gathering area. A lens could also be employed to focus IR light from a larger area onto the tip of the fibre.

Lot’s of things to experiment with.

I don't suppose there are any guides that would show me how to polish the ends?

I think I read somewhere that it should be done with wet sandpaper but I can't seem to find that information now.

cheeseslice said:

I don't suppose there are any guides that would show me how to polish the ends?

I think I read somewhere that it should be done with wet sandpaper but I can't seem to find that information now.

Click to expand...

@C
First, recut, as square as possible, using a new Stanley blade.

Then try one of the following

1. 600 / 1200 / 2000 "Wet and Dry" paper. Wet.

2. A superfine nail-file / buffer

3. Sapphire sharpening stone.

e

Metal polish + buffing wheel (Dremel or hand held powerdrill)