Articles and whitepapers
Why Wireless Lighting Control? (1/6/2006)
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
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.
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
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.