The Problem

Preconditions

Let’s assume that you are in your living room. You face a TV (probably an HD one), a cable box (and/or external DVB-T tuner in case your TV does not support the latest DVB standards), a DVD or/and a Blue-ray player, an amplifier (of X channels, hi-fi or not, AV or not) with speakers all round. In addition (depending on how lucky you are or how much you love audio/video devices) you might also be looking at some HTPC (with TV reception or not), a CD player, a projector, a satellite receiver (with hard disk or not) and maybe a Playstation 3.

The problem that we will talk about here is not the mess of cables that all these devices require (nor the power consumption of them, nor the WAF of the whole installation). The problem is that of control.

How you (or - even worse - your spouse, children, parents or great parents) manage to control all these devices and make them fullfill their purpose: serve audio and video for the ears and eyes of you and the ones near you?

Problem defined

Ok you say, so what is the problem? Each device comes with a stylish (or not so stylish) remote control that enables you (and the other users of your system) to control it. You point the thingy towards the general direction of the corresponding device, press the big red button (or similar) and presto: the device turns on (ok, it might also turn off if it was already on , but let’s assume that in that case you would skip pressing the particular button in the first place). All is well (and no problem really exists) if the device is the TV, you are happy watching exclusively whatever your TV set is capable of receiving (and decoding) and you are satisfied with the sound quality of its built-in speakers.

But what if you wanted to watch a program from cable (or DVB-T or satellite tuner), or watch a Blue-ray movie, or listen to a CD played by your DVD or CD player, or watch a series episode recorded or downloaded to your HTPC? And what if in each of these cases you would like the sound to be fed to your amplifier and be played through your (spectacularly sounding) speakers.

In any of the above cases you will need three different remote controls (one for the TV, one for the “source” device and one for the amplifier). In addition, for each different set, the “source” device and thus its remote is a different one. So you end up in the quite usual situation whereas in addition to all your glorious pile of hardware you are also facing a coffee table (or couch or side table or armchair arm) full of remote controls of various sizes, shapes and colors. Each one with its uniquely styled keys and distinct key layout.

In order to control any of the above example sets you need to juggle with the various remotes, switching from one to another, trying to memorize the key layout of each one and aiming straight (or in specific angles depending on the devices’ positioning). As an example, starting from a “whole system is off” state, if you wish to watch a program from the DVB-T receiver you have to:

It sounds like, and it is a nightmare.

And do not underestimate that you will need enough light to be able to make the remotes and their keys apart (so no dark theater room here) and also have a fairly good eysight. All of these together with the various problems inherent in the IR (as described below) constitute the problem we try to address here.

Terminology

Here are some terms that will help us clarify what we will talk about later:

A device that we use for command input/selection. E.g. a device’s factory remote control or a universal remote control.     One or more such devices must be present in any control system.

A device that we wish to control. E.g. a TV set, an amplifier etc. One or more such devices must be present in any control system.

A (stand alone) device that receives commands and marshals them to the corresponding target device. In simple setups no such device is needed. The IR sensor of a TV might be seen as such, but it is not as it is part of the TV itself.

Software that runs between a Remote Device and a Control Device and allows:

Control Software is not present in simple setups. Its presence implies that at least one Control Device is also present.

Hardware on which the Control Software is executed.

Complexity

In the preconditions section of the problem we described a system (or family of systems) which is our main concern. The problem can be further expanded in the following directions:

Technologies

We describe in this section some of the most frequently appearing communication technologies for (home) audio-video devices.

IR - Infrared

http://en.wikipedia.org/wiki/Consumer_IR

Advantages

The vast majority of audio and video devices come equipped with an IR sensor and corresponding IR remote control. Consumers are well accustomed to operating devices in this way.

You can just control your device using the supplied (included in the price) remote.

Disadvantages

There can be no obstacles between the remote and the sensor. The angle and distance between the two are limited for proper reception. Some cheaper devices are equipped with low quality remotes.

Some target devices (from the same or different manufacturers) might share some of the IR codes. So trying to control the one, inadvertently operates the other as well (with unexpected results). Same problem exists if two or more target devices (same model from same manufacturer) are present in your setup and cannot be set to receive different IR codes sets (which is a quite rare feature).

With IR the remote just sends a command to the target device. Whether the command was received or whether the command was valid given the device’s current state cannot be returned in any way. Only you (as a listener or watcher) can say what really happened.

As IR remotes with hard keys can only have a limited number of physical keys, some (on/off) functions, such as turn-on/off or mute/un-mute, are handled by the same physical key. Other functions (such as input switch, or aspect ratio selection) are usually operated by a single key that switches between alternatives. The result of pressing such keys depends upon the device’s current state. Without discrete commands the remote control system cannot reliably operate a device.

RF - Radio Frequency

http://en.wikipedia.org/wiki/Rf_module

http://zigbee.org/Specifications/ZigBeeRF4CE/FAQ.aspx

Advantages

Since no optical clearance is required for the transmission/reception of RF, the target devices might be anywhere (e.g. hidden in a closet or even in another room).

Most applications of RF are two way (e.g. cordless phones) so depending on the manufacturer and model the target device can send back an answer for each command it receives.

Disadvantages

Interferences and physical objects might limit its range

Mainly used for the emission part: an RF to IR device close to the controlled devices receives the RF signal by the remote and proceeds in distributing it as normal IR signal. A/V devices that receive and reply using RF are very rare.

SERIAL - RS232

http://en.wikipedia.org/wiki/RS-232

Advantages

Cable connection (RS232 usually crossed) between control device and target device ensures that commands are transmitted reliably.

Target devices in most cases return an acknowledge for the sent command (e.g. whether it was well formed, whether it was valid according to device’s current status, etc). For commands that are status inquires the actual device status is returned.

Disadvantages

Most reliable, allows (and in most cases implements) two-way communication. Target devices supporting Serial usually also include discrete commands and inquiry commands in their command set. Only drawback is that in order to send commands to a target device using Serial Interface, a Control Device is necessary.

IP - TCP/IP

http://en.wikipedia.org/wiki/Tcpip

Advantages

Both wired (Ethernet) and wireless (Wi-Fi) versions are quite reliable nowadays (with the former being even more reliable)

Same as for Serial

Disadvantages

But that will probably change as more and more network enabled devices are designed and hitting the streets.

Universal Remotes

http://en.wikipedia.org/wiki/Universal_remote

Universal Remotes (URs) are a solution to the problem described above. They come with a built-in database of codes from various manufacturers and models. So you can assign the ones you want to control to the UR and control them from it.

UR Characteristics

URs usually operate using IR. More expensive models also add RF (and collaborate with RF to IR converters). And the most expensive ones can also operate using Wi-Fi.

Most URs can control a specific number of distinct target devices (4, 6, 8, 18).

Portrait (most usual) or Landscape (most exotic), number of physical or touch keys, physical keys with distinct shapes, backlight, light and movement sensors.

Most URs can learn commands from an original IR remote.

Some URs can be programmed in the sense that programmable soft keys can be assigned to specific commands. Also macros, i.e. sequences of commands possibly to multiple target devices, can be defined and assigned to keys. Programming can happen on the remote itself or by connecting the remote to a PC and programming it from there (through locally installed software or web-based applications).

Early UR models operated in a device mode. At any time the UR could control the selected device only. A much friendlier way is to operate in activity mode, whereas the UR controls the set of devices that participate in the specific activity (e.g. TV, DVD and Amplifier).

Some URs offer a simple LCD area in order to help with the programming of the remote and/or convey some status info (e.g. which is the currently selected device/activity). Others include a bigger, colorful and possibly touch sensitive screen for the same reasons providing a much better interface. The screen can also be programmed to host virtual keys that are not found as physical keys, allow scrolling etc.

Advantages

Disadvantages

Hand held touch screens

Read this article for an introduction of how touch screens can be used for remote control purposes.

A solution: RemoteX4