Remote Controlled RGB Decorative Lighting Puck

Introduction

This instructable shows how to easily add some decorative lighting to a particular glass ornament but the approach can be used for many other things that can be enhanced with some rudimentary RGB LED lighting.

It is based around a cheap RGB light bulb and remote that was purchased for less than £5. However, proceed with caution as it seems that not all RGB light bulbs are the same despite the same functionality and identical looking remotes.

For the glass ornament shown above, a simple holder was made for an RGB PCB module extracted from the light bulb such that it illuminates up through the base of the ornament, when powered from a 12V DC supply. The frosted/etched finish on the glass diffuses the light to give a nice effect and the colour can be changed, within the limits of the basic RGB module, using the supplied remote unit.

The holder was cut from acrylic sheet using a small hobby CNC that I had the use of, although you can get a much better edge finish without sanding if you have access to a laser cutter. If you are good with hand tools you should be able to produce similar designs. If you have access to a 3D printer with transparent filament then you can create many different variants.

Step 1: Selecting Your Donor Light Bulb

The most important part you will need is a suitable RGB light bulb. The one I used here is the PRO-ELEC LMP-G60E27RGB03-02B 3W LED E27 RC RGB Colour Changing Lamp bought from CPC Farnell for an amazingly low price of £4.86. I say amazingly because the same part seems to be offered for much more than this from the usual eBay cheap sellers and also a lot of Chinese sellers. Even our local home supplies store has similar ones for less than £8 so perhaps there is over supply on the market and prices might be about to tumble.

Most of the cheap RGB lightbulbs are quoted as 3W and require some form of thermal management because most of the power is concentrated into one small component. My preference was to reduce the power dissipation rather than have to provide thermal management. This particular lamp is actually driven from an internal 230V mains AC to 19V DC power supply and the main RGB module uses an on board 78L05 voltage regulator for the control IC. This means that the supply voltage can be lowered to reduce the heat dissipation from the individual LEDs and provide a reasonable level of brightness whilst still powering the control IC at 5V DC.

I found that powering the main RGB module using 12V DC consumed about 32mA (less than a third of the overall current when using 19V) and gave a perfectly adequate brightness with barely any heat dissipation. You can run this back up to 19V DC if you wish to do so but beware of the increase in power dissipation. Also, unless you really know what you are doing and can ensure adequate isolation, DO NOT use the power supply from the light bulb as it is a non-isolated design will have mains and rectified mains voltages all over it.

Also, it is not worth trying to run the module from anything much lower than 12V DC since the RGB LED seems to use multiple series LED chips giving a forward voltage of between 7 and 8 volts DC.

Running at the lower voltage does slightly alter the current ration between each LED colour resulting in a slightly colder looking white. If you really wanted to I am sure you could correct this by placing the appropriate value chip resistor on top of the ones already there but that seems like to much trouble for something that will never be great. Anyway, this actually seemed to make the glass ornament look slightly more antique.

The Infra Red remote control sensitivity seems quite good but the rendering and granularity of the available colours is not great. In general, as light bulbs go, these RGB versions are not much good as the control of brightness is only 5 hardly noticeable levels and the strobe and flash modes I find annoying. However, it does have some good re-use potential with an example presented in this instructable.

Using Other RGB Lamps

There are a number of similar looking bulbs to the PRO-ELEC part, as well as different form factors, along with identical looking remotes. However, it is difficult to tell what is inside these lamps by just looking at them as you would think that they are all the same design below the skin. I did pull apart a different LED spotlight that was called 'MAGIC LIGHTING'. It was less than £4 delivered from China. The central LED got quite hot but the PSU was 5V DC and having no internal regulator, unlike the PRO-ELEC part. This makes it more difficult to drop the power on the LEDs without putting in higher value chip resistors or delicately soldering some axial ones in place. Also, the power supply had a third wire which supplied a 50Hz clocking signal to the control chip so you couldn't just use a standard 5V supply. This design did seem to be isolated but I would not guarantee them all to be like that. This PSU also got quite warm when running at full white brightness.

When power is first applied to the PRO-ELEC part, the control IC defaults to a mid power white light. The Magic Lighting part defaults to a rather more garish flashing of colours through the entire 16 colours.

Even though the remote controls looked identical, there was no interoperability between them.

The Veezio RGB lamp pictured above was found in a local B&Q store and some of the bulbs were on clearance at £4. These parts did have a distinctly different remote. Most of the components could be seen, whilst still packaged, on the PCB under the clear lens but it did not look like a voltage regulator was present and so is probably all 5V DC. The LED chip resistors looked relatively easy to modify though if you wanted to drop the power consumption by adding some more series resistance. Without buying one and taking the top off, it is not possible to determine if the PSU in the body is isolated but I would always assume that they are not.

The real take away here is that there are some parts that are easier to re-use than others and you do need to procure the same types if you want interoperability from one remote.

Step 2: List of Parts Materials and Tools

Parts and Materials Required

RGB LED Lightbulb (see previous step about variants) PRO-ELEC LMP-G60E27RGB03-02B 3W LED E27 RC RGB Colour Changing Lamp used in this instructable
12VDC @ 500mA Power Supply (the lightbulb I used drew about 32mA but there is no cost advantage in getting a lower power version but you might want to power multiple pucks)
DC barrel line socket to suit DC power supply (optional - you can just cut off the PSU DC barrel connector and solder the wires directly to the PCB)
Connecting cable (optional - if you choose to have a connector between the Puck and PSU)
Acrylic (Perspex or Plexiglass) sheet colour to suit taste (I used 3mm black and clear but this depends on your final design)
Glue (the proper glue is expensive so I used some Evo-Stick PVC & ABS glue which seems to do the job if the surfaces are flat enough)
3 x felt pads for the base

Tools Required

Basic hand tools such as pliers, cutters, strippers and screwdrivers
Soldering Iron
Access to a small CNC router and/or Laser Cutter would be ideal

Step 3: Remove the RGB Module

Assuming that you may wish to re-use the diffuser dome in your project then, using a pair of side cutters, start to nip into the housing just below the dome baseline as shown in the picture.

Nibble enough away to get a reasonably wide bladed flat screwdriver between the holder and the dome lip.

Gently prise the dome off with the screwdriver; it is only held on using a white silicon rubber sealant.

Remove the two self tapping screws.

Carefully lift the edge of the module, opposite to the hole where the wires attach, and cut or desolder the two wires.

Slide off and separate the heatsink from the PCB module and clean the grease from the back of the PCB. Note the red and green wires shown in the picture were attached so that I could power the PCB for test purposes.

Caution the PSU has 230V AC and 540V DC all over it so discard this unless you really know what you are doing.

Step 4: Design Your Puck

There is plenty of scope for plenty of different designs here as the PRO-ELEC RGB module is relatively small and low profile, as are the PCBs from other similar light bulbs.

The bare PCB from the Pro-Elec part is about 1mm thick and 47mm diameter. Some alternative bulbs look to have a smaller diameter module than this one.

All components sit just within an envelope of 43mm diameter and 3mm height, located centrally on the PCB.

The hole in the PCB next to the power attachment pads conveniently allows the cable to be fitted to exit above or below the PCB.

The sensitivity of the IR receiver IC seems good and given that even the opaque acrylics don't seem to attenuate IR light that much, the remote works well even with the PCB completely covered with black acrylic.

For this application, I wanted to place the light under the base of a glass ornament. The base measured just under 66mm diameter. The basic design that I used comprises three acrylic parts which are: -

Base (3mm black acrylic)
Retaining ring (3mm clear acrylic)
Locating ring (3mm black acrylic)

The Base ring (1) has a 47mm diameter x 1mm deep recess to hold the RGB PCB. A 4mm wide x 2mm deep channel is for the cable exit. I had to pare down the cable that I had to about 1mm the so that it would fit under the PCB. A better solution might be to use 4mm acrylic for the base and make the channel deeper or just place a hole below the cable outlet on the PCB. Another option would be to put a slot in the Retaining ring and bring the cable out from the top of the PCB. This may also be a good option if you don't have access to a CNC router.

The Retaining ring (2) is there to hold the PCB in place and needs to have hole about 43mm diameter to clear the components.

The Locating ring (3) is optional and is only there to hold the glass ornament that I was using in place and could be omitted. If you are going to make something like an RGB coaster then I suggest filling the hole in the Retaining ring with a clear non corrosive silicone or just cover retaining ring with a disc of clear or translucent acrylic. The choice of colours is arbitrary but I went for a black-clear-black acrylic sandwich such that the light would be seen out of the clear centre filling.

Step 5: Making the Puck

Having extracted the RGB module, prepare the speaker cable, or the end of your 12V DC supply cable, to attach to the PCB power pads. It is best to place the cable in the final orientation (above or below the hole) then strip and trim the ends to the correct length to align with the pads so that no undue strain is placed on the pads when finally soldered.

Once you are happy with the location of the cable, tin the ends and attach it to the PCB by carefully soldering the two ends to the two pads on the PCB. Make sure that the + and - on the PCB pads correspond with the polarity of the power supply to be used.

As I had access to a cheap Chinese engraving/milling machine, it was just a matter of designing three simple parts. The parts are simple enough that you can design them straight into CAM software to produce your G Code. I used CAMBAM, which is fairly easy to use and is relatively cheap, although the parts that I machined were simple enough to be designed and cut using the restricted evaluation version.

Once the parts have been cut out of the acrylic is it worth leaving the protective film on until you are ready to glue the parts together. Make sure the parts are OK by doing a dry fit and deburring and trimming as necessary.

When ready, remove the protective film from the faces of the base and retaining ring where they are to be glued. Apply a smear of glue to fully cover the top part of the base and a couple of drops in the cable recess. Carefully align the two together with the RGB module sandwiched in between. When you are happy with the alignment, place some weight on top to keep the parts held together for at least 30 minutes until the glue has dried.

The locating ring can then be glued in the same way.

When both parts have been glued, sand and polish the edge of the assembly as required and add the felt pads to the base.

If you are using it as a coaster, fill the hole in the retain ring with a clear non corrosive (ie does not give off acetic acid) silicone rubber enough to provide some protection from spills etc.