What is a Reed Switch?


A reed switch is an electrical switch operated by an applied magnetic field. It consists of a pair of contacts on ferrous metal reeds in a hermetically sealed glass envelope.

What is a Reed Sensor?

A reed sensor is a reed switch with a wire soldered to each end and then encapsulated inside a plastic enclosure. Lightdream’s reed sensors’ contacts are normally open and close when a magnet is present. As the magnet is pulled away the reed sensor switch contacts open.
reed switch encapsulated


What is a Controller?

A controller acts like a hub in the lighting system. It receives signals from the reed sensors, and acts on those signals by turning on or off the output.

LD2015 and LD2000 controllers

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Can a Reed Sensor be used without a controller?

Firstly the Reed Sensor contacts close when a magnet is placed next to it. This would have the effect of turning the light on with the door closed and turning it off when the door was opened.
Secondly the contacts are not designed for the current that the LED strips require and the lifespan would be quite short as the contacts would soon fuse in a closed position.

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What is the difference between the DC and AC Controllers?

The AC controller will switch mains power and has a built-in timer that will switch off the power automatically after a preset period. The AC controller has two channels and each channel can operate independently from the other. It is like having two controllers in the one unit. The timer settings apply to both channels.

The DC Controller is a single channel controller for DC voltages up to 24V. 12/24 VDC are the standard voltages used for LED lighting.

What is the difference between the LD1400 and the LD1401?

They are identical except the LD1401 has a flange at one end. This is to allow the sensor or magnet to be placed in a 10mm hole and be flush with the surface. The LD1400 has no flange and is designed to be installed into a 10mm rebate for the sensor and a 10mm hole for the magnet.

What parts do I need?

Lets say you have a single cabinet, one metre wide, with two doors and one LED light the entire width. You want the light to come on when either door is opened.
Firstly, count the number of doors and that is the number of reed sensors you need. In this case you need two reed sensor kits. Select either LD1400, LD1401 or LD1404.
Secondly, count the number of separately switched LED lights and that is the number of DC controllers you need. In this case you need the light to come on with either door being opened so need a single DC controller, LD2015.

Thirdly, you need to select a power supply. Say for example you have 3528 LED strip @ 120 LED/metre, the power consumption is 9.6W/m. For a one metre LED strip you need a power supply to have a rating of 10W or more. The voltage of the power supply must be the same as the voltage rating of the LED strip however most LED strip is 12V. A power supply can be a driver or a power adapter. A driver is better at maintaining correct voltage with variations in supply whereas a power adapter output will vary. SMPS (switch mode power supplies) overcome this to an extent.

If you have two identical cabinets as above side by side you just double the requirements but you only need one driver rated at 20W or more.

What is colour temperature?

LED strip colour temperatures range from 2700 to 5000K+.
2700 – 3000K is similar to incandescent globes at the lower end to halogen lights at the upper end.
3500-4200K is a cleaner white light and is seen in commercial spaces such as offices and shopping centres and is becoming more common in residential for task lighting.
5000K is a bluer light approaching daylight.
Be aware that descriptors such as warm white, soft white, bright light, cool white, neutral white, natural white, pure white and daylight are often applied to different values of colour temperature and should be used as a guide only.

color temperatures of various LED lights