Ikea Led Lamp

Introduction

After making my pyramid mood light with 12 high power leds, i decided to make a bigger and better version, with the newfound knowledge of possible caveats. After all, the pyramid mood lamp was more of a proof of concept with its shortcomings. I wanted the new mood lamp to be more powerful, so it could also be used in daylight conditions. I did this by using a z-power 3 watt RGB power led. This one led is far more powerful than the 12 ones combined i used before. The colors also mix better because of the wider opening angle and because the rgb chips lay very close together. But you better see it for yourself (please note: all photo's are clickable for a bigger version):

Of course a video says more than pictures, so here you can see the lamp in action with a demonstration of all the different operation modes.

Parts You Need

Here is a list of the components i used for making the led mood lamp.

3 NPN transistors capable of driving 500 mA, for example the BC337
one PIC 16F628 or 16F628A and a suitable device to program this microcontroller
a small perforated circuit board, soldering iron and skills
some 1 watt resistors (5, 10 and 15 Ohm) and a 4 channel DIP switch
a power supply (5 volts, 700 mA)
a casing, i used an Ikea Mylonit lamp
silicone caulking from your local DIY shop to fix the circuit board to the casing
one 3 watt rgb led (i purchased a z-power led here)
a little (aluminium preferably) piece of metal as a heatsink
some thermal glue to paste the heatsink and the led together

With the pyramid lamp i could still use batteries as a power source. Here i'm powering a 3 watt led, so i used one of those small power supplies you can plug into the wall outlet. I was not that satisfied with the diffused look of my previous pyramid shaped led lamp. I had to use fine grained sandpaper to transform the transparant plastic casing into a diffused, milky white one, but when you look closely you could still see some areas weren't as homogeneous as others. And thus beginneth my quest for a bigger and better casing. And one day while browsing at a local Ikea my eye fell on this Mylonit table lamp.

They come in two sizes: 31 and 45 cm high. I went with the biggest version. Funny thing is Ikea already offers this lamp in different colours. But since it's the glass that is coloured they can only light up in one color, instead of all the colors of the rainbow my lamp can show.

General Layout

Here you see the z-power led mounted on a heatsink i took from an old video card. I drilled two holes and two screws hold the star shaped led in place. To conduct the heat better i used some left over cooling paste that came with my cpu. A smaller heatsink would suffice as well, but i had this heatsink gathering dust in my closet, so...

To avoid a shortcircuit i first dipped the screw heads in some silicon paste and left it to dry. If you take a closer look at the power led, you can see the 3 individual chips for the 3 colors. This led is so bright it's almost impossible to look directly into it. Then i started building the circuit after calculating the values of the resistors. I changed the calculated values a bit by maxing each color out and looking at the color of white it produced, as i'm not a big fan of cold, blueish white. I like a warm tone better. This was how my test setup looked like:

The Circuit Board

Once everything was working like i wanted on the breadboard i soldered it all onto a small circuit board.

I cut off one corner to get a better fit in the area under the lamp. This is the schematic of the circuit.

All i needed to do now was pasting the board to the lamp with silicone caulk and soldering the 4 wires from the led to the circuit board.

Programming The PIC 16F628 Microprocessor

I have recycled _{(very ecological of me)} most of the code of my pyramid lamp, but i changed some bits (literally). Because i now have 4 switches at my disposal (the one for switching the lamp on and off isn't used anymore, now that i use a power supply) i wanted to add a random function. So you still have the modes that fade between and jump to different preprogrammed colors, but i programmed a switch for random colors which are calculated on the fly to the other modes. The third switch serves to choose between two different speeds and the last switch enables you to pause at any color the lamp is showing that moment. Here is my source code along with some guidelines to program the pic. Steve Rougier mailed me late 2009 with improvements over the original code and schematic. I recommend using his updated circuit layout. I didn't test his code myself, as i no longer use PIC's but he claims to have made several improvements. Thanks for sharing this Steve! Programming the PIC isn't that hard to do. I uploaded the hex code to the PIC16F628 with this very simple JDM pic programmer i had built before. Everything is controlled through the serial port by a PC program called ic-prog.

Conclusion

I am really satisfied with this lamp. This was what i was aiming for when i first got the idea of building my own mood lamp. I think this version definitely deserves the title 'mood lamp' because it can light up a whole room with its colors. On the left you can see the lamp still shines strong with other lights on and on the right you can see the effect when all other lights are out. In the back on the wall you can see the pyramid lamp i made earlier. I made this lamp in 2007 and during the following years tens of people from all around the world emailed me to say they had succesfully built one too. This is the last project i did with PIC's. I moved on to the arduino platform which is faster and easier to realise something with.