IR Problem

AndyH747

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Hoping someone might know the technical reason for the odd symptoms I'm getting with controlling an HDMI matrix with IR.

I have an 8x8 matrix utilising HDBaseT Lite receivers at each display which allow IR feedback to the sources connected to the matrix. However one display is built into the wall as it is a bathroom TV. The TV has an IR Out jack at the back which will utilise the normal IR receiver built into the TV. So whatever IR is received at the TV is fed to this IR Out jack. I wired this back to the matrix position and used the IR emitter and eye which came with the matrix to send the IR signals to the sources by attaching the emitter to the eye. All worked as expected with full control of all the sources via the TV in the bathroom. However the IR commands which normally switch sources do not work. I cannot switch the matrix but have full control of all the sources. I'm at a loss to explain this as the IR is obviously getting through because source control is fine. However for some reason the IR sent from the bathroom TV for source switching is being ignored.

If I take the remote used for switching sources directly to the receiving eye then the sources are switched ok so it's something to do with the IR used for switching sources not being successfully transmitted from the TV to the emitter attached to the receiving eye. However what would cause this signal to be ignored yet the IR to all sources not affected?

Any ideas why this is happening as the manufacturers are stumped and so am I!
 
Why dont you wire the output jack on the TV to the IR input Jack on the HDBaseT receiver, then the signal will be being sent in the same way as all the other TVs.

From your description you seem to be trying to switch sources externally at the matrix rather than internally as the receivers would normally do.

Maybe the matrix doesnt support this ?
 
Sorry but I've tried that. I'm using the receiver as the IR input, I just can't use the standard receiving eye. I've tried attaching the emitter from the TV to the normal receiving eye on the receiver. I've also tried using the jack directly but this didn't work either. All methods provide full source control but won't switch the matrix.

I have also tried doing it externally as you mentioned but again this didn't work. Had full source control but no matrix switching.
 
What Matrix and what TV is it ?

If the IR on the HDBaseT receiver works perfectly without the TV IR pass thru then the TV is "stripping out" the matrix IR. This could be an IR frequency issue that the TV eye cant handle.

Have you tried seeing if the matrix remote commands are being passed through the TV. Use a smartphone camera in video mode and aim at the receiver emitter. You should see the flash of IR emission on the IR emitter. Try with a source remote (Sky etc) as you know those go through then try with the matrix remote
 
Thanks for the reply.

Matrix is an HDAnywhere modular 8x8. TV is a Tilevision 22".

I'll try seeing if the matrix IR commands are actually being emitted. Hadn't thought of trying that. As you say the IR commands to the matrix appear to be stripped out. If this is a freq issue not much I can do.
 
You would need to know what the Bathroom TV is doing with the IR it Receives/Re-transmits and what range of frequencies it covers!

Joe
 
Yes but as it is successfully passing all the source IRs you'd expect it to handle the matrix IR as well. It suggests the matrix IR is on an odd frequency.
 
'It suggests the matrix IR is on an odd frequency.' - or the TV is 'Odd' :)

Not the first time I have seen problem with the TileVision IR PassThru - you may need to add in a Xantech or similar repeater device.

Joe
 
'Or find a way to add the actual IR eye from the receiver somewhere' - tricky in a wet room!

Joe
 
Not possible to use the default receiving eye. Will have to find another solution. Can switch using IP control but not as convenient as using the waterproof IR remote.

I'm using Roomie as a control system for most of the house so could use one if their IR to IP adapters which would work fine. Just a shame the only IR signal not getting through the current setup is the switching one. Have even tried using a different set of IR codes for the switching as you can teach these to the matrix. However no joy with that either.
 
I've managed to check the IR output at the emitter using the method mentioned above - thanks for that tip. Yes the IR is definitely being emitted when the matrix switching command is sent via the bathroom TV.

What I still don't understand is if the matrix is programmed with a custom IR code the matrix still cannot be switched. I can't understand why all other IR commands for the sources are getting through fine yet the matrix codes are not even though the IR is being emitted from the test above. Surely if the bathroom TV was stripping out the IR then none of it would get through and surely some of the sources would also be affected. The only info I can find on the IR used by the TV is in the interface connection manual which states the TV uses the NEC protocol for control of the TV.

The only other anomaly I've noticed is with the matrix supplied IR emitters. These use stereo jack plugs whereas most emitters use mono jack plugs. Those that use stereo jack plugs only utilise the tip and ring or the tip and body. After cutting one of the jack plugs off the emitter, I was surprised to find a three core cable. All the emitters I've used previously only ever use two cores, one for the cathode and one for the anode.
 
What are HDC/your supplier/installer saying - they are likely to have faced this problem before now.

Joe
 
That's the problem HDC haven't come across this before and they are unable to provide any further technical info on the IR protocol at present as they don't have this info immediately to hand. They're trying to get the info I've asked for but there's been nothing forthcoming as yet.

I'm the installer of this unit which is why I'm trying to solve the problem!
 
Is the Matrix IR getting through the TV (just not working with the Matrix) or not even getting through the TV?

Joe
 
It's getting through the TV fine, just not switching the matrix. However the IR must be getting corrupted as it transits through the TV eye. Some part of it must be getting stripped out. What is confusing is why this isn't happening with the source IR commands as well. However I guess it depends on the type of IR commands and frequency that the matrix uses/accepts. Without being able to analyse the IR being emitted I've no way of knowing what's being stripped out.
 
Do you have access to any form of IR Learning/capture device that will allow you to download and compare the 'Direct' vs. a 'via the TV' capture?

Joe
 
Yes I can certainly learn the code being emitted at the TV capture side but I haven't any method of actually looking at the code. I used to be able to do this with a Philips Pronto and could look at the hex code but I no longer have this. However it might be worth learning the emitted code anyway and seeing if it switches the matrix when used direct.
 
Thanks Joe. I emailed the TV supplier and they have commented as follows:

"The TileVision IR receiver uses a carrier frequency of 38KHz, with a tolerance either side of it. If the external device remote control does not use 38KHz or fall within this range, this can cause corruption of the received IR signal.

One method to try is to learn the external device IR codes in to the TileVision learning remote and then use the TileVision remote to control the external device.


The IR pass through carrier frequency is 38Khz. Usually this does not cause a problem as the tolerance of most IR receivers of external equipment will allow this frequency. Try repositioning the IR emitter, or moving the IR emitter away from the IR sensor of the external equipment.


A very long lead length can cause problems, but usually off the shelf lead length of 1 to 2 meters does not cause any problems.


The IR pass through will only drive a +5 volt emitter. A 12 volt emitter usually does not work at all, it is unknown how a 3 volt emitter fairs."

Looks like the receiver on the TV is very standard at 38Khz. I've tried using the Tilevision supplied remote but that doesn't work either even with the learned codes. The only issue might be the length of cable run utilising the IR signal. It is probably in excess of 10m. That could be the issue. However not sure why that would result is some IR working and not others.

Will keep investigating.
 

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