Sunday, October 25, 2009

Building a Multimedia Server: Remote Infrared Control

Gentlemen and occasional ladies, here is the second volume of Multimedia Server series of blogs. This covers remote infrared control of audio receivers and other home entertainment equipment. Infrared continues to be the standard for remote control of home electronics and entertainment equipments. It has two severe flaws:

  1. No talk back or acknowledgment capability
  2. Line-of-sight remote control

Infrared remote controls, per se, do not expect to receive an acknowledgment of the command that they send to home entertainment equipment. In a complimentary fashion, home entertainment equipments do not care to send an acknowledgment to the infrared control that the command that was issued has been executed. This situation is like a deaf and blind person giving a command to a dumb and blind person. Both of them are blissfully unaware of the real status of each other. This is not a real problem when home electronics equipments are in the line-of-sight, since you can view the status of the equipment directly. However, this becomes a real problem when you have to hide all that home entertainment equipment in an old shelf in your basement, garage or attic.

Let us first solve the problem of "line-of-sight". A couple of years back, there were tons of complicated solutions that required installation of expensive infrared distribution hubs and wiring. Now this issue has been resolved by several manufacturers in innovative ways. These devices are called remote control extenders. Here is how I have quickly classified them:

  1. Type 1: Universal Remote Control and several other remote control manufacturers make remote controls that generate UHF signal in addition to infrared signal. In addition, they make a base station that converts UHF signal back to infrared signals. Unlike infrared (IR) signal, UHF signal is not blocked by walls.
  2. Type 2: Powermid type of signal converters, which receive the IR signal and convert that signal to the RF signal. At the other end, a Powermid receiver receives the RF signal and converts that back to the IR signal.
  3. Type 3: X10 infrared signal receivers, which receive the IR signal and convert that into an X10 signal, which you can use to control and X10 power control device to turn the equipment on and off.
  4. Type 4: Insteon infrared receiver and transmitter devices that can receive infrared signals and convert them to Insteon signals and vice-versa.

There are several other solutions like z-wave and more expensive professional-grade IR distribution systems. I briefly looked into these other systems and dropped them from my list since either they were too expensive or I was unwilling to spend time to learn an unfamiliar technology.

Type 1 Non-line-of-sight Infrared Remote Control Solutions

I use a URC (Universal Remote Control) MX600 remote control with MRF-250 base station. You can find more details on these on www.universalremote.com website. This remote control takes a little getting "used to" but give it a little time and I can assure that you will begin to love it. You will need to use IR emitters (with 2.5mm mono male plugs, if you are using MRF-250 or you will need 3.5mm mono male to 2.5mm mono male adapter, if you are using IR emitters with 3.5mm mono male plug), since IR blaster generally causes an overload of IR signal, if it is too close to the audio equipment. Since I have MRF-250 too close to my audio equipments, I found it quite unreliable. Therefore, I've used IR emitters all over. I recommend using triple head (or 3-eye) IR emitters, which will allow you to remote control up to 18 different devices, for instance, satellite receiver, 300-DVD jukebox, audio receiver, subwoofer amplifier, etc

Type 2 Non-line-of-sight Infrared Remote Control Solutions

I liked X10 Powermid device for converting IR signals into RF signals.

You can find a lot more details about this device on www.smarthome.com. However, I did not like pointing my remote all the time at this device. Secondly, this pyramid shaped device was breaking the décor of the family room. Therefore, I decided not to use it. Here is a stock picture of Powermid remote control extender device.

If you are already using X10 protocol for home automation, I understand that Powermid will allow you to convert IR signals to X10 signals over home power line. I haven't tested this feature though.


"Next Generation" Remote control extender is conceptually similar to Powermid. However, the "Next Generation's" transmitter in this case is hidden in the battery compartment of your remote control. It cleverly replaces one of the 1.5volt AAA or AA batteries in the battery compartment of your remote control with a half-size rechargeable battery of 1.2volt and uses the remaining space to insert a tiny RF transmitter. The half-size rechargeable battery and the RF transmitter are in an AAA sized sleeve. For AA size batteries, you insert AAA-sized RF transmitter sleeve into another AA-sized sleeve. This remote control extender seems to be quite popular on www.amazon.com with more than 500 positive reviews. The best benefit is that you can continue to use your existing remote. However, I came across two major issues with this remote control extender. These are as follows:

  1. The spaceship shaped RF receiver that converts RF signal back to IR signals has only one 3.5mm IR emitter jack behind it. Therefore, if you are planning to use IR emitters, you can't control more than six devices. The reason is that the most eyes IR emitters have are six. I tried a 3-eye IR emitter and it was quite effective. I did not try 6-eye IR emitter.
  2. Each remote control unit will need a transmitter and a rechargeable battery. If you have used a "learning remote control" to transfer all the IR commands for various home entertainment devices to a single remote control then that solves this problem. However, I found that rechargeable batteries had to be charged frequently. The battery charger is in the spaceship shaped receiver. Therefore, if your home entertainment devices are located in your basement, you will have to go there each time you needed to replace the rechargeable battery.

Type 3 Non-line-of-sight Infrared Remote Control Solutions

These are X10 infrared receivers that receive an IR signal and convert the IR signal into an X10 signal. Now you can use other X10 devices, e.g., X10 appliance module, to control your remote home entertainment center. The problem is that your remote control will be limited to the controls allowed by X10 hardware. In addition, X10 is not a reliable protocol for communication, since similar to IR remote controls, it does not send an acknowledgment. On the other hand, the benefit is its low cost of ownership. I tested X10 model IR543, which can control four X10 modules. In general, I'd not recommend it for controlling power to your home entertainment devices.

Type 4 Non-line-of-sight Infrared Remote Control Solutions

These are powerline+RF communication devices that send an acknowledgment. One of the protocols developed by SmartHome (www.smarthome.com) is Insteon. For instance, SimpleHomeNet's EZUIRT can work as an IR distribution hub. You will need two of these transreceivers. One to convert IR signal to Insteon signal and another one to convert Insteon signal back to IR signal. Alternatively, you an use IRLinc to convert IR signals to Insteon and then use EZUIRT to convert Insteon signals back to IR. I'm using an IRLinc to dim lights while watching movies using the same remote control that I use to control the multimedia server and home entertainment devices. Perty cool, eh!

Solving the Problem of Lack of Acknowledgment

This requires using an acknowledgment based reliable communication protocol to supplement IR signals. The way I have done it is that I've used Insteon-based low voltage input/output control modules (e.g., I/O Linc) to send a signal to a KeyPadLinc button, when a device is turned on or off. Therefore, when I turn-on my multimedia server controller (Helios, now discontinued and manufacturer closed down) using my UHF remote control MX600, Helios sends a signal to SimpleHomeNet's EZIO Input/Output relay controller through a 110v to 6v 100ma DC step down transformer. EZIO sends a corresponding Insteon signal to KeyPadLinc device in my family room, which lights up the LED under that button confirming to me that multimedia server controller is turned on. Please refer to SmartHome website for more details on Insteon-based home automation modules.

Some of the newer models of audio receivers now have TV output of status, e.g., volume control, channel select, etc through HDMI output. This is another way of solving the problem of lack of acknowledgment. I found it best to use a combination of methods to achieve the degree of control that best suits your needs.

Finally, a couple of words about remote control of the desktop PC that works as my multimedia server. I have discussed this topic in more detail in my earlier blog on infrared control of a ReadyNas device. I'm providing a link here. Therefore, I'd skip this topic. I've used the same method to soft-on and soft-off my desktop PC using infrared remote control. Basically, what I've done is that I've added an infrared controlled power switch in parallel to the existing push button switch that turned-on and turned-off my desktop PC. Let me confess that I tried the PC remote control devices and USB IR receivers as shown below in pictures but decided to give them up due to following reasons:

  1. I found that the software had spyware built-in
  2. USB ports do not have standby power, therefore when desktop PC is turned-off, I can't turn it on using USB IR receiver

I have included a brief description of these USB IR receiver-based PC remote control devices because you never know, what did not work for me may work for someone else.

In my next blog, I'll be discussing the setup and configuration of multimedia controller and server.