Articles and whitepapers

Why Wireless Lighting Control? (1/6/2006)

By Paul Wafer, Rako Controls

The advantages and benefits of 'scene setting' or mood lighting control systems have been discussed in previous articles, but if the requirement for such a system is to be taken as a given, then the discussion must focus on the possibility and practicality of installation. Traditional systems have typically comprised a dimming box or rack that houses the power electronics, to which all of the lighting cabling is brought back, and from there a data cable of some type is wired to the switch plates.

This cabling is completely different to a normal domestic wiring scenario. It will involve major electrical works, and the probability of having to re-decorate after walls have been chased out to pull in the data cables. The reality is that the initial cost of the equipment can be dwarfed by the additional cost of installation.

Faced with these issues, a number of manufacturers are now producing wireless control systems which obviate the need for extensive re-wiring. With wall panels that communicate to dimmers via RF (Radio Frequency), and dimmer receiver modules small enough to be pushed through the cut-out for a 50W downlight, it is now possible to completely retro-fit a scene control system into a property using the existing wiring. Furthermore, dimmers can be wired in-line with the flex of a table lamp or up-lighter and plugged into a standard 13A socket.

Small dimmer receiver modules

Most systems will use battery-powered wall panels. Assuming that battery life is three or more years, these wall panels highlight one of the big plusses of wireless, namely scalability. No longer is adding an extra wall plate to a room one of those 'You should have thought about that earlier' situations. Simply screw a new plate to the wall and the job is done.

Battery-powered wall panel for dimming and controlling four scenes

As with anything in life, there is no complete panacea, and a system will still need to be planned, and in some instances, such as wall lights, modifications to the power wiring may still be necessary.

What types of wireless system are there?

The most simple systems available use infrared 'wall box' dimmers. These just replace the existing light switch, and are limited to single-room applications. Radio frequency-based systems have the advantage of not needing line-of-sight with the dimmer, and so suit both single- and multi-room projects.

Reliable operation is essential with a lighting system. To provide this, manufacturers have a number of choices open to them, each with pros and cons. For the RF systems, there are a number of different carrier frequencies used. The most common two are licence-exempt systems using 433.9MHz and 868MHz. These relatively low frequencies are widely used due to their excellent range capabilities. Many budget systems however, tend to be AM-based and not FM, which can prove a problem with signal strength and consistency of operation. Some systems are based on the commonly-used 2.4GHz frequency. These usually have to rely on 'mesh' network technology due to the higher frequencies being absorbed by water and building materials. Indeed how many of us have used WiFi at home with a laptop and found it will work in one room, but not the next?

Since RF travels through walls, it is imperative that any system has a method of coding both rooms and circuits within a room in order to avoid crosstalk with either neighbouring rooms, or indeed with the neighbours! A common concern is the possibility of spurious interference from other RF equipment such as garage openers or car key fobs, but in reality, any reputable supplier's kit will have more than adequate protection against this in the form of an addressing system. In this case, it is important to pick a system that supports enough addresses to not only cope with the planned installation, but also future additions, as this is a major selling point of wireless solutions.

Hybrid systems

As installers use more wireless systems, and confidence in the technology grows, 'hybrid' systems are evolving. An example of such a system is the Rako RAK-4. This provides a practical solution where a property is being re-wired with a centralised dimming position, but offers the wireless benefits of no data cabling to the switch plates.

A client may wish to commit to lighting controls to all main areas of a property, but maybe not as far as the guest bedrooms and bathrooms. With a hybrid system such as the RAK-4, the main area lighting loads can be hard-wired back to a central dimming position, and the RF wall plates will then control the lighting as would a traditional hard-wired solution. Come the time when the client wants to make additions, in-line dimmers can be introduced to the conventionally-switched circuits. RF wall plates then replace the switches, and the whole system, both hard-wired and in-line dimmers, all operate seamlessly from the RF wall plates, as well as via audio-visual, time clock, and SMS text message interfaces.

Hard-wired Rako RAK-4 dimmers in the cupboard controlling the downlights, and an in-line dimmer controlling the table lamp

Conclusion

With consideration and a little planning, a wireless lighting system can be installed with all the feature sets of the more complex hard-wired systems. Given all of the interfaces now available to link with home control systems, multi-room audio products, security, and a whole host of other home automation products, wireless lighting is now a reality, not a dream!

Paul Wafer is a Director of Rako Controls Ltd, UK manufacturer of Wireless Lighting Controls.

www.rakocontrols.com