Rabbut's Diy Led Rig

[rabbut]

Well, many know I've built a DIY LED array, and many have expressed an interest in the nitty gritty details on it. So, without further a-do;

The array is about 2ft by 15", holding 30 LED's in total. That's 15 Blue and 15 White. They are computer controlled with the blues fading on over an hour, before the whites fading on over the hour after the Blues first started. The whites run full tilt then for 8 hours, the Blues at about 2/3 of full power, before the Whites fade down over an hour, followed by the Blues. The top fans, shown below are on from when the Blues start fading on, and remain on for half an hour after they finish fading off, before the computer turns them off for me

There are air in-takes on the opposite side roughly in line with where the LED heat sinks are, to blow the cushion of hot air off the top of the sinks to keep the LED's cooler, as below

The smaller holes are the air in-takes, the large fans are actually air extractors from the main tank's air pocket above it. They should remove hot and humid air from the tank area, after the tank fans have done their stuff. These have an air temperature sensor inside the cabinet that switches them on and off as needed. Likewise the tank cooling fans below, that have a temperature probe in the tank

All the sensing and computing is done inside the "magic box" at the side of my tank, built into the cabinet. In there about 30 wires connect to various bit and bats in part of the rig I fondly refer to as "spaghetti junction", as that's what it look like I will point out that all those wires are only needed due to the computerised dimming and temperature controlled fans though, for just on and off LED's, you'll probably have a less daunting 5-6 wires to connect up below the rig

*Picture of Spaghetti Junction coming soon...*

So, what gear is essential to making an LED rig?

1) Well, LED's are the obvious one... I'm using third generation Luxeon Star's in Royal Blue and Warm White for my rig, but Cree and Seoul also do suitable LED's that are main-stream, well priced and easy to get. Actually, Cree and Seoul use the same emitters (the bit that makes the light basically) and just package them differently With Whites, you want ones that emit a full spectrum, not just three prime colours to get white, as the Luxeon Rebles do. Start a new thread if you building your own LED rig and need info on whether the ones you are looking at will work, and someone (not necessarily me, others in FW have build DIY LED's also) will get back to you...

2) Constant Current Drivers. I'm using Black Cat drivers, but Luxeon make Buckpuck's that are suited, as do MeanWell and many, many more manufacturers. Ignore the wattage ratings on drivers when you buy them, look instead at the current rating and maximum voltage, as these are more important to you for working out if they are any good. The Voltage says how many LED's you can run off one driver, and the Current says if they are the correct model for your LED's. The driver's current needs to be slightly less than the LED's maximum current tolerance rating. Again, if that's unclear for your own rig, post your own thread as for the LED's.

3) Heat sinks. Heat is the main killer for LED's so you need to get it away from them. They may be small but they do get warm. The Luxeons "burn out" around 150c, and they'll get that warm without heat sinks within about 15s of running at full power without cooling. I'm using generic computer chipset heat sinks for mine. You need a layer of Thermal Paste between the LED and the heat sink though to transfer the heat to the heat sink better... Many have mounted all the LED's onto a custom made heat sink and mounted the sink over their tank. A few also use "strip light style" heat sinks also...

4) Cooling fans. Unless you are using very big heat sinks, you'll need some fans to blow air over the heat sinks and keep the LED's cool enough to operate. I'm using 12cm Akasa PC case cooling fans, as you can see above

5) What am I missing? Erm... Something essential.... Like, erm.... A power supply? Yer, one or two of those could be useful I'm using a Laptop PSU (well two actually), one that can supply an extra 25% of the current needed by your drivers at the Voltage you are running at. Don't run on the edge of what the PSU can do, it will lead to it getting very warm and shortening it's life. A small short somewhere down the like could make this component a fire hazard if under-powered also, so don't skimp here Again, if you don't know what you need, post your own thread and ask

Optional Extras

Well, computers can be used to control the LED's if you like, to get nice fade effects, simulate lunar cycles, cloud cover and sunrise/sunset. Arduino project boards, such as the Duemilanove that I'm using and the Mega boards are popular choices for this. They can be programmed in Java rather than machine code, making life a lot easier. See the Arduino home page for more information. Obviously, computer control adds more complication to the rig, and to use the computer to actually dim the LED's. With Buckpuck's, you can feed the Arduino's output directly into the control pin to dim. With mine, I have to use transistors to connect the control pin of my drivers to a common ground whenever the output of the Arduino goes high... This area of actually controlling the dimming is where most rigs get more complex, so I'd strongly advise posting your own thread if dimming is something you'd like on your rig to ensure you have the correct gear to do it before you break something, if anything is slightly un-clear For instance, if I did the Buckpuck "stick the Arduino onto the control pin" on my drivers, I'd fry the LED's and possible the driver, as the control pin is an internal reference, so the "added voltage" from the signal would lead to the LED's being "overdriven", or having too much electricity pushed through them, overheating them and killing them off Dimming is actually simple if you know what you are doing with electronics, so don't be too put off by it, but I also understand many people running away screaming at this point

Also, you can use a Variable Resistor (often in the form of a Potentiometer/"Pot", two variable resistors in one, that change in relation to each other) to control the light output. How you wire it up to work depends on the driver you are using, but it essentially acts like a primitive dimmer. On my drivers, you'd wire the common pin to ground and one of the two local pins to the control. You dim your LED's by turning the dial...

There are also other optional extras I've seen people play with, like an in-line resistor on the LED string to warm up the LED's colour output, or applying another voltage to the string to cool down the light out-put. The latter can lead to issues of over-driving again though, and dead/dieing LED's if not done carefully...

What did my rig cost then, and where did I get the stuff?

15 Third Generation Luxeon Star Warm White LED's in the three Watt version. They cost £3.12 each delivered through an Ebay seller. It was a one-off auction however. You can buy direct from Luxeon though

15 Third Generation Luxeon Star Royal Blue LED's in the three Watt version. They cost about £3.50 each delivered through an Ebay seller in another one-off auction. Again, available direct from Luxeon.

6 Black Cat 970mA Constant Current Drivers. These were through an Ebay seller, teap0t42, and cost about £6 each delivered (bulk buy shipping discount applied).

3 RAM heat sinks, cut in half, to cool the drivers (they get warm in use). Cost £4.99 each from Maplins

30 Generic Computer Chipset heat sink, £2.50 each from Ebay seller virtualvillage-uk-rho. (don't use that seller in a rush, postage was slow, but what do you expect from China...)

10ml tube of Thermal Paste £14.99 from Maplins

2 Akasa 120mm Computer Case Cooling fans, £9.99 each from Maplins

*Optional Component* 6 Open Collector NPN Transistors (any type will do), the ones I used cost £1.49 each from Maplins

*Optional Component* 6 470 Ohm Resistors, 11p each from Maplins

*Optional Component* 1 Arduino Duemilanove project board, £28 from Cool Components

*Optional Component* 30 25 degree Lenses to make the LED's beam narrower... About 20p each from Ebay seller auspicious.e The delivery was slow and these lenses required modifications to get them to fit the LED's they were supposed to fit though...

So, that's a total spend of around £308.78 for my new light rig, excluding cooling for the tank and air-gap. One down, one to go for the Discus After some more saving up

Control *Optional*

This may be of interest to those folks that want to computer control their rigs, the code from my project...

// Marine Tank LED fading on/off program

// By Rabbut on Tropical Fish Forums

// Written on 17/06/2009



int bluevalue = 255;									  // Variable to keep the actual level for the Blue LED's

int blueledpin = 9;									   // The Blues are connected to digital pin 9

int whitevalue = 255;									 // variable to keep the actual level for the White LED's

int whiteledpin = 3;									  // The Whites are connected to digital pin 3

int fanpin = 2;										   // The Fans connected to digital pin 2

 

void setup() 

{ 

   pinMode(fanpin, OUTPUT);							   // Set-up the Fan pin

   digitalWrite (fanpin, LOW);							// Turns the Fans off

   analogWrite(blueledpin, bluevalue);					// Sets the correct level to the Blues

   analogWrite(whiteledpin, whitevalue);				  // Sets the correct level to the Whites

 } 

 

void loop() 

{

 delay (41400000);

 digitalWrite (fanpin, HIGH);							 // Turn on the Fans

   for(bluevalue = 20; bluevalue >= 8; bluevalue-=1)	 // Fade in the Blues at Eleven Thirty 

  { 

	analogWrite(blueledpin, bluevalue);				   // Sets the new level to the Blues

	delay(276923);										// Waits Five minuites before incrementing the output further, for a 1 hour fade time

  } 

	delay (12);

	for(whitevalue = 20; whitevalue >= 0; whitevalue-=1) // Fade in the Whites at Twelve Thirty 

  { 

	analogWrite(whiteledpin, whitevalue);				 // Sets the new level to the Whites

	delay(171428);										// Waits Three minuites before incrementing the output further, for a 1 hour fade time

  }

  delay (1);

  delay (28800000);									   // Wait for Eight hours before starting to fade off the Whites

  for(whitevalue = 0; whitevalue <= 20; whitevalue+=1)	// Fade out the whites at Nine Thirty

  { 

	analogWrite(whiteledpin, whitevalue);				 // Sets the new level to the Whites

	delay(171428);										// Waits Three minuites before incrementing the output further, for a 1 hour fade time

  }

  delay (12);

  analogWrite (whiteledpin, 255);  

  for(bluevalue = 8; bluevalue <= 20; bluevalue+=1)	   // Fade out the Blues at Ten Thirty

  { 

	analogWrite(blueledpin, bluevalue);				   // Sets the new level to the Blues

	delay(276923);										// Waits Five minuites before incrementing the output further, for a 1 hour fade time

  } 

  delay (1);

  analogWrite (blueledpin, 255);  

  delay (1800000);										// Wait half an hour until Midnight

  digitalWrite (fanpin, LOW);							 // Before turning the Fans off and re-starting the loop

}

The commenting should make it self-explanitory to anyone whom has Java coded before. If you haven't copy that into your project when you have the Arduino project and play arround with the numbers to see what they do. As it is, if the Arduino boots at midnight, the fans and Blues come on at 11:30, whites at 12:30, then whites off at 12:30 and Blues at 22:30, with an hours fade from each mentioned point. Note the big jump at fade-on time. This is because Black Cat drivers dim Logariytmically on PWM control from the Arduino, and that jump is required to actually see any light from the LED's when you want them to come on

Sorry for the wall of text and the no doubt evident lack of Proof-reading
Rabbut

Well, I've just proof-read it, corrected a few spelling issues and added a couple of components (the fans) in the parts-cost list that I missed... I've amended the spend accordingly also.

 

[degsod]

It looks good mate, I have a small LED system on mine, and will deffo install on my 6x2x2 when I get it. I will also look at the computer control. Do you have to reboot the program every day at midnight?

 

[TigerIssey]

Nice one Rabutt, Thank You.

Will have a good look through it and have a look at the components you mention.

Will you be doing a wiring diagram at all??

 

[rabbut]

The program runs on a continuous loop. When it gets to mid-night it "re-sets" itself. After initially starting it up though after programming/re-programming/power failure/clock adjustments in spring/autum though, you would have to press re-set at midnight to "syncronise" the things clock with "real-time"

EDIT to add, I *may* have a play with a wireing diagram at some point, but not tonight. My head hurts after that

 

[TigerIssey]

Wwwoooooo, did not mean now chuck, I am not going out tomorrow to get all the bits and start.

Just generally whether you would do one, I find them easier to understand.

Thanks again

 

[degsod]

The program runs on a continuous loop. When it gets to mid-night it "re-sets" itself. After initially starting it up though after programming/re-programming/power failure/clock adjustments in spring/autum though, you would have to press re-set at midnight to "syncronise" the things clock with "real-time"

EDIT to add, I *may* have a play with a wireing diagram at some point, but not tonight. My head hurts after that

Sounds good, I will deffo include something like that in my next project.

 

[xxBarneyxx]

Nice write up mate

 

[rabbut]

Thank you Barney. I remember you mentioning you were thinking about LED's at some point? Hope that hasn't put you off too much

I might think about a wiring diagram today at some point, one of the basic "on/off" LED style project, as well as how mines been done. For simplicity, I'll dot-out repetitive bits, so I'll only show one LED string, and the three LED's in the middle of the string will vanish behind dots...

All the best
Rabbut

 

[TigerIssey]

That Rabutt sounds wonderful

Thank you very much.

What wire do you use to connect everything up??

 

[degsod]

On my first rig I used speaker cable which was quite thick, on my second one I changed it becausee the cable from the drivers was very thin so being a computer guy I used cat 5 cable which was nice and neat as you get 4 twisted pairs in a single cable.

 

[keenonfish]

Wow, it's nice to see high powered led's coming down in price

Nicely done Rabbut, looks very professional. Shame all that excess heat can't be used to supplement the main tank heater/s, someone's got to attempt that one soon surely

BTW that programming looks very neat, almost makes me want to learn java . I tried to imagine what it would look like in assembler, I would have to sit down with pen and paper for that one

Olly.

 

[xxBarneyxx]

I was planning on doing an LED rig but the amount of money it would cost to buy the parts just to make something that matches my T5's at the moment is too much. Still considering maybe making a couple of small LED rigs to go alongside my T5's to create a few extra bright spots for SPS and a clam.

 

[TigerIssey]

Barney, that is kind of what I will be using it for. It makes sense moneywise as you will not have the running costs of the T5's plus its the T5 tube costs for a 6ft tank that put me off adding extra T5's especially when really after 6 months they need replacing. LED's don't need that constant replacement.

 

[rabbut]

Handily, the Arduino programming thing assembles the Java into Assembly. It comes in at about 18,000 bytes of the 30,000 maximum the Arduino can handle, so about 560 lines assuming 32bit base... That would take more than a sheet of paper to muddle out in assembly Heat was the main reason for me to install LED's the Halide made too much heat. I've seen one person water cool them, so you could probably make a dig that cooled the heat into the tank, but what an expensive mess you'd make if a pipe slipped off and salt water got onto the 'tronics

Where possible, you want a nice thick and high-purity copper cable, to reduce resistance and hence increase efficiency. Audio cable therefore is best, I used 2mm copper equipment cable, and Twisted pairs are OK for small strings. They'll melt with higher powered rigs, most TP's being rated at about 20W. My strings are 15W each (six strings of five). Past 15W on TP wire, the cables will get hot and waste a lot of power...

All the best
Rabbut

 

[FishBeast]

Very nice setup dude! I am currently working on a setup which will house between 3-5 high output RGB leds controlled by the PIC 16f628a microcontroller. Although I find myself becomming overwhelmed with the coding side of things. Are you using the ATMega8 chip? How is it to program?

I want my project to replicate sunrise/sunset in a tropical tank. Also I after the sunset I want to fade in the blue spectrum for a moonlight. If I can pull this off I will be very happy, and so will my fish!