A futuristic funking-up of my own living room lighting, much to the wife’s dismay I suspect.

When it comes to lighting, I’ve always been a bit of a fan of doing something modern and different. Not to put down anybody else’s tastes, but personally I don’t like luminaires which pretend to be something they’re not such as modern PIR electric lights designed to look like olde-world oil carriage lamps, or brass light switches in the ‘Georgian’ style... not that I imagine many Georgians had light switches in the mid 1700’s, although if they did then they wouldn’t have been of much use as it was another hundred years before Swan/Edison popped up with the bright idea of the electric light bulb.

Anyhow, I’ve always preferred something with a rather more space-age or industrial appearance, so not long after moving into my current abode in 2002 I installed a fluorescent light into the living room.

Yes, fluorescent.

Actually, it was an SES (E14) bathroom wall light that I converted into 4-pin TC-L fluorescent and then recessed into the living room ceiling. This was before Part-B of the building regulations sprung up to say you shouldn’t go cutting dirty great holes into your plasterboard ceiling without fire stopping it, but there you go, it was the olden days... at least it was as far as my kids are concerned.

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So, above is the before shot showing the rectangular fluorescent light in the ceiling. The dome thing behind it is a disco light for... well... all the great parties I have with my hundreds of friends. Also note the coving around the edge of the room. I used to think that looked really smart, now it just seems... somehow... dated.

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The fluorescent light had the look at the time, but its illumination was harsh on the eyes of course. We didn’t use it much and preferred to use two floorlamps of an evening.

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And then one Saturday morning at the beginning of April this year, I decided it was time for an overhaul. I wanted an edge-lit room with the ability to set the desired colour from a controller giving a ‘wall wash’ effect. Putting in a bit of research over Easter, I decided to install a Ledridge DMX controlled lighting system with hard wired wall controller, all supplied by SRM on the Budbrooke Industrial Estate in Warwick. This solution consists of RGB LED tape cut to size and mounted on an aluminium heatsink all the way around the room. The colour can be set to straight RED, GREEN or BLUE, or can be colour mixed to a cool white with all three LED elements on full together. By varying the brightness of the individual elements, you can also make other colours (i.e. red and green make yellow etc.) You set the colour from the controller using the iPodesque touch control dial, or you can activate a preset program that either selects a specific preset colour, flashes through the primary colours or cycles through the available spectrum of colours with user-definable speeds from slow to fast.


The touch dial sends the colour to a DMX controller which the RGB LED tape is connected to. This block diagram shows how my configuration fits together. As I’ll mention later, for this project I have installed two RGB ‘zones’ that operate independently, but more DMX controllers can be daisy chained if your controller supports multiple zones.


The DMX controller takes the information supplied by the wall controller and converts it into DC voltage pulses sent to the separate RGB LED elements on the tape. For the sake of example, in order to make purple, a continuous 12v is sent to the blue channel, while the red channel may get a 12v pulse for just a few milliseconds before it is switched off for the same amount of time, then switched back on again. This makes the red channel half as bright as the blue as it is being pulsed on and off continuously, but mix bright blue with dim red and you get a purple colour. Meanwhile, the green channel is doing nothing. The rate of the pulsing is high enough that the human eye can’t detect it, so the light appears as dimmed rather than as flashing.

That’s a simplistic example, but by pulsing the different channels at varying rates, the brightness of the individual elements can be controlled to 'mix' the light output into a wide array of colours. This pulse modulation is also how the dimming option works – the dimmer you want the lights, the shorter their ‘on’ pulse periods are and the longer their ‘off’ pulse periods.


When it comes to pulses, an even square wave will have a 50% duty cycle, i.e. half on and half off. Where the duration of the mark time (Tm) differs from the space time (Ts), the amount of light given off by any one colour can be varied greater or lower than 50%. In the above diagram the blue channel has a long mark time and a short space time, while the red channel has a longer space time resulting in the blue light appearing brighter than the red light because it is being powered on for longer. Assuming the green channel isn’t doing anything, the resultant colour would be a shade of purple. Widen the length of Ts in proportion across these channels and you still get the same purple, but it becomes dimmer.

Going back to the physical installation, with the coving ripped down I still had a flat ceiling but nowhere to hide my LED strips. Simply putting them around the edge of the room would look messy. To give myself a gap around the edge of the ceiling to physically hide the LED strips, I needed the ceiling to be lowered all over except for around the edges. This would give me an edge trough in which to install the strips and other associated gubbins such as the DMX controllers.

Now, mention to many jobbing builders that you want your ceiling lowered for these kind of shenanigans and I suspect you’ll get short shrift. Fortunately, I knew a local family firm who were up for the task. In the meantime, I had the idea of installing a second RGB zone, independently controlled to the outer edge lights and appearing in three cut-outs along the middle of the ceiling.

Actually, these three central lights would be something of a hybrid. As well as being RGB controllable, the electrics that served the existing ceiling light were still in place, so it made sense to install some basic white 230v LED lighting that was nothing to do with the RGB elements but would operate simply as practical lighting for the room when needed. I did this partly because I was worried that my edge-lit solution may not be bright enough if the room needed to be lit practically, but I need not have bothered as the RGB lights are sufficient on their own. Still, the old light switch and feed were in place, so I may as well make use of them.


Above shows one of the three central lighting clusters. In the middle is a 230v R7s LED lamp and on either side of it is an RGB LED strip mounted on aluminium heatsink track. These are attached to the old ceiling plasterboard and the new frame for the lowered ceiling will be built around them.

Once my first-fixing was complete, the builders got cracking and motored through one of the hottest days of May to construct my boxing made of a wooden frame which was then plasterboarded and plastered.

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When done, I had my lowered ceiling with the edge trough measuring about 15cm wide and 15cm deep.

I wanted to provide a cover to diffuse the light all the way around, but needed a way to hold it in place. Using a laser line, a wooden beading edge was affixed around the edge of the boxing and the walls of the room to give me a lip all the way around that a cover could sit upon.

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Once this was in place, the aluminium heat sink track was installed all the way around the outside edge of the box and the RGB strip was stuck to the track using its 3M self-adhesive backing.

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The RGB strips are supplied in five metre lengths and are each supposed to be connected to their respective DMX controller in parallel. The manufacturer doesn’t recommend exceeding five metres because the volt drop may affect performance. That said, I needed 13m of strip to get around the boxing, and the DMX controller was right next to the start and end points for the loop. Because of this I figured I might be able to reduce cable runs by connecting my two five metre and one three metre strips together in a ‘ring’ configuration. Although the furthest point would be over five metres away from the controller, with two parallel paths to play with the effects of voltage drop are reduced. As it turned out, the hunch worked and the RGB strips function perfectly throughout the entire length in my case.


Once the plaster had dried, I cut out the middle sections of plasterboard where the zone 2 RGB lights and 230V white lights were located. To frame the central lights, I used.. well.. frames – actual picture frames from Next. Some opaque plastic was used to line the glass to mask the physical appearance of the wiring and hardware behind while also diffusing the light shining out. The entire room was repainted in matt white to best show off whatever colour was to be displayed.

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To construct the covers to go around the outside edge, I used sheets of clear polystyrene as these were easily cut to shape.

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I went for the 4mm thick stuff as I didn’t want it flapping around, but one 1200x600mm sheet would yield about four 1200mm long strips, so in the end only about three and a half sheets were needed. The polystyrene sheets were cut accordingly, then to make them opaque one side was sanded with an electric sander.

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The strips then simply sit on top of the beaded edges all the way around the room. They can be lifted out for maintenance and cleaning as required.

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When switched off, the strips hide the DMX controllers, wiring and any visibility of the LED tape. When switched on, they diffuse the light nicely.

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Let’s take a closer look at the component parts....

The DMX controllers and LED tape run on 12V DC although some models use 24V. Either way, a fairly beefy piece of power supply equipment is required. The total power consumption for my zone 1 and zone 2 lighting project (14 metres of LED tape overall) clocks in at about 7W per metre so that’s about 100 Watts. That’s a fair amount of juice for lighting a domestic room these days. Ledridge can put together the component parts for you and they wholesale through SRM in this neck of the woods. The power supply they provided me isn’t going to visibly sit well in any newly designed room, and with a cooling fan you’ll know it’s running. In my case I installed it in the room next door which is a storage area for the business. It can whirr away all it likes in there.

IMG 0142The power supply has been mounted high on the wall to keep it out of the way, but with exposed terminals I'll need to find a way to cover it without compromising the ventilation.

When designing something like this, due consideration needs to be given to the location of the control and power supply parts. They should be somewhere ventilated but accessible, yet out of sight.

The individual DMX controllers are smaller affairs, and in my case I was able to site them in the trough around the edge of the room along with the LED strips. Pictured is the zone- one controller with its RJ45 input from the wall colour dial and its RJ45 output to the zone 2 controller located on the left, while on the right is the DC input and RGBW output. In my case I’m using RGB rather than RGBW strips, the latter having an extra set of white LEDs fitted to provide a true white rather than one created by colour mixing. The wires have been painted to help keep them masked. It doesn’t look pretty, but they won’t be seen.

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In order for each DMX controller to be associated with a zone on the wall control, DIP switches have to be set according to the following diagram Ledridge kindly supplied to me.


The wall controller is a LTECH DX8 capable of controlling up to four zones. I’m only using zones one and two at present, but I’ve sited the controller in a central location in my open plan living area as I intend to extend into the dining room and kitchen with new zones there in their own right.

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You can select multiple zones to set them to the same output, or control any zone independently to the others. The MODE button allows you to select a program preset for certain colours, an RGB flash mode or a smooth colour changing mode. The SPEED/BRT button changes the speed of the flash/smooth colour change, or if held down it will alter the brightness up or down.

Interestingly, the RED, GREEN, BLUE and WHITE buttons do not set the named colour, but they remove that colour from the current output. As stated before, purple is made of red and blue, so if you have purple light and you press RED, the red will be removed leaving you with just the blue. It’s a bit strange, but it does allow you to switch off individual channels within the selected zone meaning you can turn one or more zones wholly off while others remain on.

The iPod-like touch dial allows you to swipe your finger around to manually select the colour of your choice. The only other thing to mention about the touch controller is that it requires a neutral unlike a normal light switch, so if retrofitting something like this then unless the neutral passes through the switch position, new cabling will have to be installed.

I took the decision to hard wire my touch controller to the DMX controllers, but the LLTOUCHDX8 does have an in-built transmitter and Ledridge also offer a receiver option. This allows you to site the touch control away from the DMX receivers without having to run an additional signal cable which could be useful in some installations. They also offer the ubiquitous mobile app so you can control the lighting from your phone, but I’ve written before about how I don’t like apps that may be here today and gone tomorrow. Call me old-school, but I know that a physical cable between my wall controller and DMX controller will be more bulletproof than a radio signal or a WiFi app.

When it comes to the signal wiring, normal shielded CAT-5 twisted pair is fine to use. The DMX controllers have RJ45 inputs and outputs, and standard off-the shelf patch cables can be used so long as they’re of sufficient quality, or you can make your own if you know how to properly crimp an RJ45.


Only two wire pairs are used, the orange pair to carry the signal, and the brown pair for ground. For my controller, I cannibalised a redundant old shielded DSL modem cable that was lying around, replacing one RJ11 end with the required RJ45 and wiring the other directly into the terminals on the back of the controller.

Technical support from Ledridge was very good, and a deserved shout goes out to Bianca and Jess who provided fast answers to my queries on DMX addressing, wiring and touch controller operation, as well as their assistance alongside Iain, from Warwick's branch of SRM, in making sure the right component parts were ordered in the first place.

All in all, I’m very pleased with how the project has turned out. Besides the novelty of being able to set a different slant on any given evening by having such control over the lighting, it can help to add a level of immersion when the right colours are set for the planned entertainment as we found when watching Tron last week.

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This sort of project isn't cheap to put together but, working with a reputable builder, this kind of bespoke lighting is something we can offer. If plain old ceiling pendants and lampshades are proving a bit boring for you, then get in contact and we'll look to put together something more exciting to meet your needs!

If you want to see a video of the installation, and why wouldn't you, then you're in luck as eight minutes and thirty nine seconds of your life can be lost on my YouTube channel where you'll find more about this particular project complete with wobbly camera work and a cheesy synth backing track! Simply click below and resign yourselves to it people!

Update 30/12/17

A demonstration of the LTECH DX8 controller can also now be found on my YouTube channel: