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Infrared Distribution in a Structured Wiring System

Introduction

In order to make my switching system ‘Wife Compatible’ (verified) I had to devise a simple and bulletproof method of managing it. At first it was a web portal but I realized fairly quickly that not only did it have to be simple, it also had to be in context and unfortunately browsing a website while trying to control the TV is not in context for most people.

What is in context? Why a remote control of course.

Read on for the full scoop..

My Pronto

After surveying what my options were I pretty much settled on the pronto controllers. They are cheap, easy to get and very flexible. In general I hate touchscreen remotes, I’m too tactile for them, but in this case it fit the bill perfectly.

I gave it some hard thought and realized that essentially each switching configuration comes down to a two item combination, Place and Task. Once you know both of these you can tell the switching system to make the change. For example, in ‘AutoPatchese’ switching input 3 (Tivo ) to Output 2 ( Office ) is the command ‘CI3O2T’ ( Change Input 3 to Output 2 Take ). Easy enough, now its just a matter of navigating the screens in a way that makes sense.

If I am trying to watch something on TV the first fact I have is that I know where I am. Since I know where I am I can tell the Pronto Remote where I am and this is precisely what my ‘Home Page’ on the remote does.Each room of the house is represented on this screen (granted I don’t have a very big house!). I originally toyed with the idea of actually have a blueprint of the house represented on the screen but I never could get it to look quite right and in the end this format was a lot easier to comprehend and adjust to.

Once my location is determined the Pronto loads the associated device list that is available for that room. In my case every device is available in every room although this is by no means a requirement. I just create a file that has a button for each component in my system. The catch here is that even though the bitmaps are identical the actual file is unique per room because I have to transmit a unique I.R. code to identify each combination.When pressed this I.R. code is transmitted, received by Girder and then Girder issues the appropriate switching command ( ex:CI3O2T )

As a nicety I then switch the Pronto to the control map for that component. No one ever uses this, they just pick up the actual Tivo remote and get to work.But its a nice touch and always draws a smile.

How do I get my I.R. codes? Luckily the Pronto ships with a huge library of pre-determined I.R. codes and thanks to some wierd derivative of Moore’s law most of these I.R. codes are assigned to equipment long obsoleted by the march of technology. My personal favorites are early LaserDisc codes. Something like ‘Stop’ on Pioneer LaserDisc player ends up representing the switch of my Media PC to the Living Room.

I.R. Distribution

This code is beamed into my I.R. switching system that is comprised of components from Xantech such as the DinkyLink reciever and a powered I.R. switch. Distributing I.R. is painfully simple, you just need 6 wires (3 pair in telco speak) and a standard Cat5 has 4 pair so that does nicely and leaves me a pair left over for POTS (Plain Ole Telephone Service). 3 wires are dedicated to send and 3 to receive.

You simply:

1. Wire your receive wires from the I.R. receiver to the related Cat5 wires
2. On the other side you drop those into the first 3 slots on a standard 6 pair telco distribution block.
3. On the other end of the telco distribution block you pass the signal into the I.R. repeater input for signal amplification. (this is now your reception bus).
4. On the I.R. repeater output you wire it BACK to the telco block but now on the other 3 slots. (This is now your transmit bus) .
5. Wire your I.R. emitters to the transmit bus. This includes both the other 3 cat 5 going BACK to your room of choice as well as a few I.R. emitters for your media closet to control your Tivo, DVD player, Media PC etc.
6. Wire the 3 transmit wires into your room local I.R. emitter if required. Usually not if you centralized your components.

This image shows Cat5 coming in from the rooms in my home (Green Cable) and entering the telephone distribution block (green circuit board that is long and rectangular). The blue cable on the end connects the 3 pairs (6 wires) to the black box on the right which is the amplified I.R. switch/repeater. The black wire coming out of the top of the repeater is my emitter and it actually loops down and back up to the small black block you see towards the bottom/center of the image. The orange/white wires coming out of that feed back into the Telco block for I.R. emission to the rooms. Here is a secret, you really only need TWO wires for I.R., the 3rd is ’signal’ to turn the red L.E.D. on when sending and receiving. Above this is the large POTS distribution block so that every room has a phone running on the same infrastructure. The nice thing about this is that if I ever get multiple lines I can wire them into the block and switch that particular room to the new line. Telco Lineman the world over are thanking me for not having to climb under my house ever again. Your Welcome!

This scheme allows you to basically shoot any remote at any TV in any room and have the I.R. output blasted to -all- other rooms *and* the Media closet.

In the Media Closet I have a USB-UIRT plugged into my Media PC as well as an MCE2005 remote receiver (to control my Media PC). The USB-UIRT picks up the Pronto codes via Girder and then Girder handles the heavy lifting of converting ‘Stop on a Pioneer Laserdisc’ to ‘CI2O3T’ via RS-232.

And thats how you control a whole house A/V switching system using I.R. Distribution and an old Pronto remote you got on ebay for $45. The next step is to build an I.R. switching appliance and get the $2000 media PC off of serial switching duty. This will make the system more bulletproof and actually allow me to make it useful to the homes next occupants (this is California and we generate wealth by moving every 3-5 years). It’ll also be a darn fun project that utilizes REST, Ruby on Rails and embedded linux but thats fodder for another article entirely..