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The two minute guide to lighting control in the smart home

Andrew Brister 10 November 2010
The two minute guide to lighting control in the smart home

Lighting control in the home can create different scenes or moods, can aid security and improves energy efficiency. Ian Trudgeon of thinkingbricks looks at the things you should consider when planning a project.

Lighting control is also known as dimming. The basis of dimming is to switch the lamp on and off very quickly, up to 100 times a second. The human eye cannot detect the change, and actually perceives more light than is actually output from the lamp. For example, when a 50% light level is set, the eye perceives approximately 70% light.

The lamps in a property are divided into a number of circuits, of which there may be several in one room. By changing the level of lighting across the circuits in a room, a number of lighting scenes or moods can be set. These can adapt for changes in the use of a room, or to highlight different areas in the room, or across the property as a whole.

Instead of the standard switch, a key pad with a number of buttons gives the client access to the different scenes, using buttons 1-4 for example.

Specifying lighting control accurately is about understanding the loads present on each circuit. A load schedule is created by calculating the number and wattage of the lamps on any circuit. Once this is in place, a lighting control system can be designed to control the various circuits correctly. For example, 10 x 50W halogen down lighters would have a load on the circuit of 500W.

Lighting control systems can also control other elements, or can activate relays to automate devices alongside the lighting, for example window blinds. 

One touch control
Buttons on the keypad can be programmed to turn all the lights off across the property (normally from the master bedroom or other nominated point). Similarly, a keypad in the entrance to the property can light specific rooms, for example the kitchen to make a welcome home scene.

Lighting control can make the house appear occupied. By selecting a button on the keypad programmed as “holiday”, the client can press and leave the property to replay the lighting use within the house over the last few weeks, which adds security via lighting control.

Linking the security system can mean that alarms will trigger whole house lighting, or flash external lighting to help find the property quickly.

Efficiency
By reducing the output of lighting, even by 10-15%, the energy spent lighting a home can become more efficient. This will also increase the lifespan of the lamps by 200-400%. Lighting rooms only when occupied also aids efficiency, linking infrared sensors to the controls for the room.

Using a central time clock, lighting can be brought up gradually to match the daylight levels, rather than being switched immediately to full power.

What types of lighting can be dimmed and what can’t?
Conventional lamps, such as the common GLS and halogen lamps are simple to dim. With the advent of LED technology and increasing use of energy-saving lamps such as compact fluorescents, the challenges of dimming are much higher.

It may be that different types of lamp are used in the same room. A key limitation in dimming LED lighting, for example, is the low loads that the lamps have (sometimes less than 1W); some dimming racks cannot cater for such low loads.

The answer is that the majority of lighting can be dimmed, with the right cabling in place (for control), and the right specification of lamps and dimming equipment.

A solution that will deliver for the client is always possible by talking through what is required and planned between the lighting specifier and the lighting control system installer.

Ian Trudgeon is project director with thinkingbricks. He is offering RIBA-certified CPD courses on all aspects of home technology.

www.thinkingbricks.co.uk/architects-and-technology.htm

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