Instructables

RGB Color Controllable High Power LED Room + Spot Lighting

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Color Controllable High Power Lighting - no longer for billionaires only! Build your own fully color controllable RGB room or spot lighting for under $100. Perhaps you are asking yourself: "why would i want an any-color light?" well, for starters you can give your pets a virtual color make-over! ever wondered if Fido might look better in purple? perhaps you'd like to see your makeup the way Bono's seeing it with those blue-lens sunglasses? or maybe you're sick of your almond-white wall paint and want to give it just a tweak of eggshell today? of course, it's a gimme for the dance-party, but you can also use it to tweak the shade on your existing room lighting, or as a standalone to get any shade of white (and perfect color rendering) - invaluable for visual arts. in search of an existential crisis? i just spent a good half an hour with this light staring at my hand and trying to figure out what color it is *supposed* to be. Recently i've been using it as a portable personal light-space. you know - you walk around with an ipod to have your own sound-space, no you can walk around bathed in your own personal color too!

Specs:
- Controller can power up to 360 watts of LED lighting - between 3 and 100+ power LED's
- Analog dial or slider for Red, Green and Blue - create an infinite number of light colors!
- easy to make a room light or a spot light by switching lenses / covers
- very fine analog control for precise color matching (or white matching)
- Includes current-limiting protection circuit
- Simple 7-component thru-hole circuit - No microcontrollers or programming!
- Controller cost: $25
- 50-watt, 15-LED lamp cost: $50
- Efficient: 50 watts of LED light equals 100 to 150 watts of incandescent light.
- Efficient: 80-90% controller efficiency
- Controller can be used with a variety of power sources
- Recycled materials & electronics: 20-40%

I've included a lot of detail in this instructable that applies to any power-LED project, and i've got several other power-LED instructables too, check those out for other notes & ideas. 

why not digital?? this controller was specially designed to be as simple as possible by using analog-only. it turns out that it works really well. yes, a digital PWM controller is "better", but it requires "chips" and is thus more complicated to build. i've included a circuit for a digital PWM controller here.

This article is brought to you by MonkeyLectric and the Monkey Light bike light.




 
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laurage2 months ago

Hello,

Which GE Silicone-2 did you use? From what I read there is a very wide range of them. (Or would any do?)

I have really had a gut full of the electrical LED  power supplies... wasting power and all the BS with the designs etc.

So I came up with a VERY simple way to run and control LED's.

Assuming the power supply is 12V - or on a charging car battery - say 14.2V.... or even 15V for the silver / calcium car batteries...

OK just for simplicity's sake we will have a 12V power supply.

Each LED has a PEAK forward voltage.... which is only relevant for the amount of current in the supply. I have run single 3.5V 20ma LED's on 240V mains supply with only teeny capacitors to limit the current  - they were getting 200V... and almost zilch milliamps... and they ran quite dim.

So OK assuming that the 3W LED's peak forward voltage is 3.9V.

Each LED has an internal resistance - and with enough of them in series - they LOWER the available voltage to each LED - thus acting as the current limiter at the same time.

So if we add 4 LED's in a string and run them on the 12V, we get a total peak voltage capacity of the LED's at 15.6V, thus giving each LED 3V - which is about 20% less voltage than the "accurately regulated voltage and current supply".

Less voltage = less current - so the LED's will also be a bit dimmer, but you will also have more of them...

QED.

It's really just a case of suck it and see.

For 2.2V LED's on a 12V supply, I'd be using say 8 of them in series to start off with and then perhaps dropping to 7 LED's in the string.

There is a magic point of about 15% less voltage than the peak forward voltage that gives enough resistance to stop thermal run away from occurring - and the light is still quite bright, and you have an extra LED or two in the series...

AND you don't have to mess around at all with any BS current limiting circuitry.

Doing the calculations, getting the parts, making the circuits, and they also tend to waste power etc.....

This way - dead reliable, and slightly dimmed LED's last almost forever.

Hi Wrogerwroger,
you made a point here. In your 240VAC power supply example did you put the LED's as the rectifier diodes in a Greatz rectifier brigde driving the complete LED string to get no loss from the rectifier as well? The bridge LED's would be dimmer I guess than the rest.
hossa231 year ago
Hey there,

I tried to assemble a circuit like that with 4 SEOUL LEDs of each color (R42182, G42182, B42182), however the 10k slider I added does not seem to work like expected.

With my 19V power source I can switch only between like 13.2V and 12.9V incoming to the LEDs. It joes does not dimm anything...

No matter what resistors I use with R1/R2 (tried several combinations, even plain trial&error), even without any resistors the circuit is just lighting. Without of course at maximum brightness.

Anyone got an idea where I have failed here? (Also have some 12V computer power supplies laying around if that would be all it takes...)
dlhylton2 years ago
Wow, your way is a lot more complex than mine. I basically take a full voltage and a nail and bolt and just place it on the heat sink.

http://www.learningaboutelectronics.com/Articles/Why-attach-a-heat-sink-to-a-voltage-regulator

But great job on putting this together. Great stuff.
goldFlake2 years ago
hay man thanks for the hint of running the 1 watt overspec..
i have also sinilar led costs .3 USD here ( yes 1/3 rd of a dollar us ) in pakistan.. they say its one watt.. i tried it running at 750mA it was muchg much brifghter but was also very hot .. so i returned back to 350mA usng pot .. so i think if i attach a large number f these to a pc heatsink and attach a 12 volts (1.5 Watt) dc brushless fan it can be very bright as well as cool and give more life ? what r ur words? have u over driven it ? can u share more info ..
bjcryss2 years ago
when mounting the VREG with a TO220(or similar) casing, how did you manage to get the screw that holds the VREG to the heatsink, not to touch the inside of the hole in the VREG ? I always had this problem, how did you resolve it ?
stp715a2 years ago
Hi. Have read all your material with great interest and appreciation. Thank you. Have built your LM1084 circuit many times for LED projects. The lastest is interesting in that I designed a 1.55A array using a 0.4 sense resistor (actually 2 X 0.8 ohm sense resistor in parallel). When I measure the amperage while the circuit is ON the reading is a steady state 600ma and no where near the 1.55A the circuit should draw. Any ideas or suggestions appreciated.

Thanks again for all the helpful instructables.
Super_Nerd2 years ago
I have an idea. Due to changes in the light's enviroment like temperature, time, or weather they change to preset colors.

ex.

60 degrees and under bright blue

Sunny Day Yellow

Get home from work/school Cyan
Trimaran3 years ago
I wonder if Q1 getting really hot in a short time is normal. It is similar to the one used in this instructable.
That is normal - hence the big heat sink. The more power the regulator dissipates, the more you have to sink.
mglipton3 years ago
I am using an LED with these stats:
2.9V @ 700mA
3.35V @ 3A
I want to control it up to the max current. Seems you define R3 for a single current. Do I calculate that with the max (3A) current, giving a 0.2-Ohm resistor (closest value)? Thanks!
I'm wondering, could this potentially be used to "wash" a wall with blue or green while having foreground objects lit with "white" light. The reason I'm asking is this might be used as a "magic" portable blue or green screen for video composting. Yes? No? Maybe? Go to hell?
that should work. i dont see why not. try it, that's the only way to see.
should work, as long as your wall isnt too reflective
im pretty positive that wouldn't work at all.... good idea though, and companies like datavideo actually sell chroma key kits that work with a retro-reflective screen and a ring of green/blue leds around the camera lens

Datavideo CKL-200 Dual-Color Chromakey Light System

 




Spuzzum3 years ago
They sell thermal epoxy specifically for heatsinks.. a lot better than silicone. In fact, that's what the reefer led supply shops recommend if you don't drill and screw the stars down. "Arctic Silver Premium Thermal Adhesive".
drfusion3 years ago
Hey, having a little trouble getting this to work right. Mostly it seems the resistor combinations I use won't turn off the LEDs(voltage not low enough) and won't turn them up high enough. I'm using LED's with FV of 3.2 and max of 3.75. Using a 2k pot. 19.5v supply. The LM1084IT-ADJ. What should my R1 and R2 be? Thanks!
Never-mind, I figured it out. Ended up with R1=680, R2=2.7k. I had blown the regulator chip earlier experimenting and didn't realize it! :) Dropped in a new one and presto! Thanks, this circuit deserves grand kudos!
aRnonymous4 years ago
Great instructable!! I really like it, but there is one question that comes to my mind.

Lets say i have a power source V and a luxeon Led, and Resistor(R1) in between that makes the led shine in full power.
and now i insert in between a pot meter in series, This would change the resistance of the circuit lowering the current, meaning making the led give off less light, never allowing to go above the R1 value which is the max.
now do this three times for RGB and you got the same project with simpler circuitry don't you? why wouldn't that be good?

why do you choose to use voltage regulator and transistors?
 
This is my only question before i start making this instructable so could someone please explain this in detail to me? Thanks
Because the potentiometer would start smouldering and eventually fail completely.

Say the current flowing through each LED is 700mA (0.7A) which is quite common for high powered LED's. Now, if the voltage across the LED is 3.2V (full brightness), the the power being dissipated is: P=IV = 0.7*3.2 = 2.24W. If you connected a potentiometer in series with this LED then it would also have to be capable of dissipating this much power. However, most pots have an absolute maximum power rating of 0.5W which is well below what is necessary, which is why it starts smouldering.

Using the voltage regulator, the current on the input branch (the one with all of the resistors in it) is kept very low and therefore the power dissipated by each resistor is very low. But, the current in the output side can be SET (using R3) to anywhere up to 3 or 5A depending upon what voltage regulator you use.
Hello! This project is amazing - I would like to make it for some friends of mine that just got married and a house. They built their own bath tub, which is amazing in itself. Now, they would like to have some rgb LED's to light the tub romantically and who am I not to provide? But I would like to offer them some dynamics and a remote. I have found the following product:

http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=/specs/LDRF-RGB4.htm

but I am not quite happy since the analog driver that makes this project so beautiful is not included, which is neigh impossible with a remote I imagine. Anyway, do you have any advice for me? Thanks in advance!
ledpwr3 years ago
I just finished making my own rgba light (yes it has amber as well !) You can see it here.  It puts out over 2400 lumens at 80watts! Thank you Dan for the best instructable ever!
DSC00361.JPG
gonzabarra4 years ago
is very exelent, and veri prolijed
nanozap4 years ago
I've been using the more "simple" current driver with NFET, NPN, and R1&R2, and it has work great for 1watt, 3 watt and 10 watt LEDs.
I'd like to construct the controllable driver with voltage regulator for use with (2) 10 watt LEDs; V= 23 volts, current = 1000ma. Cut off voltage =18 volts, max voltage= 23 volts. I'll use the 2.5K pot for R4. I need to figure values for R1&R2, but I am math/calculation deficient ,Any help will be appreciated.
DanCat6 years ago
Hi, id like to know how you cut your board. Like what tool did you use? thanks.
Looks like there's a hacksaw in that photo. That's likely what he used.
 I found this controller shield for the arduino. Does anyone know that, if properly combined with this instructables controller, it could be used to control the system. it has 10 K potentiometers and other useful inputs and controls . i figure that if the programing was done right, it would make an excellent controller module. please respond ASAP and give me advice.

www.sparkfun.com/commerce/product_info.php
modulis4 years ago
Here you can see my assembly. It cost me about $200 here in Latvia.
Used single 10W led for each colour. Also I used potentiometers with switch, so I can turn off each chanel completely without the VREG burning. The hardest part in all this was getting the right R1 and R2 and insulating the VREG.
DSC_0164.JPG
modulis modulis4 years ago
forgot to say thanks to Dan :)
excellent instructable
rawdog794 years ago
For 1W LED's, would 80 degree C wire be safe enough to use?
rawdog794 years ago
Thank you for all the responses!
BJCK19905 years ago
Has anybody found a new website that sells these LED's. It seems that the links he posted are now dead.
ebay is usually the cheapest.
Briguy95 years ago
What I was saying before I deleted my own comment was:

Three Things:

1. The link http://www.lumiledsfuture.com/ is outdated, you should remove it.
2. The other link http://www.futurecb.com/ works fine, but
3. In the FutureCB link, there is a parenthesis at the end of the link, making it so you can't directly access the site from the link. You should edit the link so the parenthesis isn't messing up the link.
Briguy9 Briguy95 years ago
Oh yeah you should also replace LumiLEDsFuture with FutureElectronics.com
will a different type of npn transistor work, not many a stores sell them, and cbf ordering one
I've got everything I need for this project but my potentiometers/sliders are slightly different in terms of the legs, it has five pins on each side. Attached is a diagram and some pictures (sorry bad quality). Can you please help. Tell me which leg goes to which wire. Thanks
p_1.pngp_2.pngp_3.pngp_4.png
I would say the extreme corner pins are mounting pins to create a reinforced attachment to the circuit board and the two clusters of three pins are for TWO separate potentiometer tracks. Possible from a stereo system or something.
As a matter of fact you are right, I went to my electronics teacher and he wasn't too sure either so we used his multimeter and worked out that it didn't matter which side you would solder because it gives the same output. The very outer pins are for mounting, the single inner pins are the input and the two inner pins are the variable output. Its like on a circular potentiometer it has three pins and two are the variable output. My teacher said that if you solder them together it will give you both low and high variables of resistance.
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