Dream Chip Build Thread
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The 3 x 100 led chips (100 led, not 100 Watt) cost me about $430 for the chips, plus $250 for the coolers, or about $680.
I figure I'll spend about another $100 on drivers and such.
Keep in mind, this is for 3 LEDs with the maximum equivalent power draw of 750 Watts, if driven at 1.4A each.
I plan to run them at 180W each, or 540W total.
I figure I'll spend about another $100 on drivers and such.
Keep in mind, this is for 3 LEDs with the maximum equivalent power draw of 750 Watts, if driven at 1.4A each.
I plan to run them at 180W each, or 540W total.
Two would probably be adequate to cover a 4'x2'x2' 120 gal.
I have a 5'x2'x2' 150 Gal, and I'll be using 3 for coverage - probably with 60 degree lenses for penetration.
Hanin has a 180 Gal (I believe), and he also has 3 - I don't know if he plans to use lenses.
With a deeper 210 Gal (72"x24"x28") you may need 60 degree lenses and possibly 3-4 LEDs.
I managed to get the last 3 that the seller ac-rc had from a group buy, so it's likely the only way to get more is to do another group buy or get lucky and piggy-back on top of another.
Edit: Something along these lines is what I was thinking of for controlling the drivers:
http://code.google.com/p/jarduino-aquarium-controller/">http://code.google.com/p/jarduino-aquarium-controller/</a>
<div class="gc_ifarem_title">Meanwell LDD-1000H with Arduino - YouTube</div>
It's pretty neat, and the driver chips (LDD-1000H) can dim down to 0%.
My 3 x 100-chip Dream Chip LED's are on their way.. should be here in about 10 days.
I had a further conversation with ac-rc about future group buys:
So for a future group buy of the Dream Chip LEDs, if they become popular, the total cost for 50 x 100-chip versions would be around $9,000...
We shall see - they have been getting some good reviews on other sites for a few months now.
I had a further conversation with ac-rc about future group buys:
So for a future group buy of the Dream Chip LEDs, if they become popular, the total cost for 50 x 100-chip versions would be around $9,000...
We shall see - they have been getting some good reviews on other sites for a few months now.
Doing some more research, I think I might go with this
http://www.arctic.ac/en/p/cooling/vga/455/accelero-mono-plus.html">http://www.arctic.ac/en/p/cooling/vga/455/accelero-mono-plus.html</a>
Rated for 200w.
http://www.arctic.ac/en/p/cooling/vga/455/accelero-mono-plus.html">http://www.arctic.ac/en/p/cooling/vga/455/accelero-mono-plus.html</a>
Rated for 200w.
I placed an order for 15 of these MeanWell LDD-1000H 1-Amp LED driver chips:
http://www.powergatellc.com/mean-well-ldd-1000h-dc-dc-converter.html">http://www.powergatellc.com/mean-well-ldd-1000h-dc-dc-converter.html</a>
I plan to use 5 on each Dream Chip LED, which will allow me to control each LED channel on each LED separately.
At less than $5 each in these quantities (>10), they're cheap enough and small enough that I can mount them on circuit boards.
They each take a PWM signal for dimming (down to 1%!), so the idea is to build an Arduino LED controller that can handle generating 15+ individual PWM signals to control the whole thing.
The LDD-1000H's will get their power from a 48V DC power supply, wattage to be determined...
http://www.powergatellc.com/mean-well-ldd-1000h-dc-dc-converter.html">http://www.powergatellc.com/mean-well-ldd-1000h-dc-dc-converter.html</a>
I plan to use 5 on each Dream Chip LED, which will allow me to control each LED channel on each LED separately.
At less than $5 each in these quantities (>10), they're cheap enough and small enough that I can mount them on circuit boards.
They each take a PWM signal for dimming (down to 1%!), so the idea is to build an Arduino LED controller that can handle generating 15+ individual PWM signals to control the whole thing.
The LDD-1000H's will get their power from a 48V DC power supply, wattage to be determined...
Yep, these are DC-DC drivers, and this module limits the max current to 1000mA.
They have lower end versions for 350mA, 700mA, etc...
I got my 3 x Dream Chip LEDs plus the heatsinks and adapter plates this morning, I'll post some pictures soon.
The LDD's support a wide range of voltage, up to 54V DC, and they'll step down to whatever is required to power the LED string.
I placed an order for 15 LDD-1000H's, and they're backordered - should arrive early April.
But for less than $5 each, I can wait.. I think the order total was like $75.
I plan to draw up a circuit board to hold up to 16 of these LDD's, each channel controlled by an Arduino-generated PWM signal.
Nice thing about these drivers is if the PWM signal is at 0% (or <0.8v, ground), the LDD turns off the LED.
Also, I ordered a 48V 480W 10A AC-DC power supply on eBay, which will be enough power to drive all 15 LED channels.
15 channels @ 1A max @ 32V = 480W
48V @ 10A = 480W
So you'll never be able to fully drive the chip as each channel is rated for 1400mA?
Yes, you wouldn't be able to fully drive the chip... But I don't think you'd really want to, for heat and power consumption reasons.
Even AC-RC's par readings didn't have ALL the channels on at 1400mA, they had all on at 1A (5A total):
Got my Dream Chips and the heatsinks from AC-RC:
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These heatsinks are different from normal computer CPU heatsinks, in that they're made for cooling GPU's (video cards).
These in particular are nice because they're symmetrical on the left-right direction, which should allow for making a case/cover for the LED assembly a lot easier... They're also relatively short, making for a smaller assembly size.
The real useful part is the adapter plate - since the holes on the heatsink base are almost universally the same, it makes for an easy method to mount the LED to the heatsink.
The heatsink even came with an instruction sheet with dimensions, small heatsinks for GPU RAM chips, and thermal paste...
The 120mm fans are also quieter, and they use a 4-pin wire which makes it easy to control for speed.
Two of the wires are for 12V and Ground, the third wire gives you a tachometer signal for reading the fan RPM, and the fourth wire accepts a PWM signal to control the fan speed.
These heatsinks are different from normal computer CPU heatsinks, in that they're made for cooling GPU's (video cards).
These in particular are nice because they're symmetrical on the left-right direction, which should allow for making a case/cover for the LED assembly a lot easier... They're also relatively short, making for a smaller assembly size.
The real useful part is the adapter plate - since the holes on the heatsink base are almost universally the same, it makes for an easy method to mount the LED to the heatsink.
The heatsink even came with an instruction sheet with dimensions, small heatsinks for GPU RAM chips, and thermal paste...
The 120mm fans are also quieter, and they use a 4-pin wire which makes it easy to control for speed.
Two of the wires are for 12V and Ground, the third wire gives you a tachometer signal for reading the fan RPM, and the fourth wire accepts a PWM signal to control the fan speed.
Opened up one of the LED packages, and was pleased to find it came with a thermal pad for the back.
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alt="" /></a>
The thermal pad can take the place of thermal paste in between the LED backplate and the heatsink or adapter plate.
I also noted that the wires are a relatively thin 22 gauge wire, but they're covered in silicone rubber sheathing for protection from heat.
The thermal pad can take the place of thermal paste in between the LED backplate and the heatsink or adapter plate.
I also noted that the wires are a relatively thin 22 gauge wire, but they're covered in silicone rubber sheathing for protection from heat.
This http://www.reefcentral.com/forums/showthread.php?t=2222702">thread</a> on RC has had a long-running DIY thread on using the Meanwell LDD drivers with Arduino, and one of the persons there drew up a 10x10cm [IMG]http://www.reefcentral.com/forums/showpost.php?p=20968604&postcount=297">circuit board</a> that can hold 5 x LDD drivers for wiring them up.
I placed an order with the files for 10 boards from ITeadStudio.com, the total cost was about $35 for 10 boards.
I'm probably only going to end up using 3-5 of these boards, so if anybody's interested in a few, hit me up.
<fieldset class="gc-fieldset">
<legend> Attached files </legend> [IMG]http://atlantareefclub.org/boards/data/uploads/attachments/840835=43364-5UP-LDD_HPcb.png>
class="gc-images" title="5UP-LDD_HPcb.png[/IMG] style="max-width:300px" /></a> </fieldset>
I placed an order with the files for 10 boards from ITeadStudio.com, the total cost was about $35 for 10 boards.
I'm probably only going to end up using 3-5 of these boards, so if anybody's interested in a few, hit me up.
<fieldset class="gc-fieldset">
<legend> Attached files </legend> [IMG]http://atlantareefclub.org/boards/data/uploads/attachments/840835=43364-5UP-LDD_HPcb.png>
One of the design features I wanted to implement was individual channel dimming control with the Meanwell LDD-H driver chips.
Since each LDD-H driver can accept a separate PWM signal, and each Dream Chip LED has 5 channels, for 3 Dream Chips that's essentially 15 separate LED strings to control.
The problem is that most Arduino boards, even the newest http://arduino.cc/en/Main/ArduinoBoardDue">Arduino Due</a> (my board of choice) only has 12 PWM output pins.
This meant finding a extra circuit board that could handle generating multiple PWM signals, and there are two chips that are popular for that:
<ul>
<li>[IMG]http://playground.arduino.cc/learning/TLC5940">Texas Instruments TLC5940</a> - This chip is a 16-channel PWM generator that can be used to directly drive small LED's (the small 2-pin round ones, not like Cree's).</li>
<li>[IMG]http://www.nxp.com/documents/data_sheet/PCA9685.pdf">NXP PCA9685</a> (pdf link) - Also a 16-channel PWM generator for small LEDs.</li>
</ul>
They both have mostly the same capabilities:
<ul>
<li>16 Channels</li>
<li>12-bit dimming (4096 levels of dimming!)</li>
<li>Daisy-chainable (connect multiple boards together - want 96 PWM outputs? 6 boards.)</li>
</ul>
However, the TI TLC5940 while popular has a crucial flaw - its PWM channels act as a [I]current sink</em> (negative or ground), and not a [I]current source </em>(positive).
The LDD-H PWM input requires a positive voltage of up to 6V DC, with a current source providing 0.1mA - a tiny amount, but still it needs to come from a [I]current source</em> and not a [I]current sink</em>.
The PCA9685 [I]can</em> provide the same capability as the TLC5940, and its PWM outputs can provide up to 10mA of current per pin - perfect!
It also has a PWM frequency of up to 1000 Hz / 1kHz - lights flicker at 60 Hz, so at 1000Hz the dimming will be super super smooth, in combination of 4096 levels of dimming.
You'll be able to dim at 1% without flickering.
TL;DR:
I'm going to buy one of these [IMG]http://www.adafruit.com/products/815">Adafruit PCA9685</a> driver boards to use for driving the LDD-H drivers.
The Arduino will control the PCA9685 board, which will control the LDD-H drivers... and let there be light. :)
Since each LDD-H driver can accept a separate PWM signal, and each Dream Chip LED has 5 channels, for 3 Dream Chips that's essentially 15 separate LED strings to control.
The problem is that most Arduino boards, even the newest http://arduino.cc/en/Main/ArduinoBoardDue">Arduino Due</a> (my board of choice) only has 12 PWM output pins.
This meant finding a extra circuit board that could handle generating multiple PWM signals, and there are two chips that are popular for that:
<ul>
<li>[IMG]http://playground.arduino.cc/learning/TLC5940">Texas Instruments TLC5940</a> - This chip is a 16-channel PWM generator that can be used to directly drive small LED's (the small 2-pin round ones, not like Cree's).</li>
<li>[IMG]http://www.nxp.com/documents/data_sheet/PCA9685.pdf">NXP PCA9685</a> (pdf link) - Also a 16-channel PWM generator for small LEDs.</li>
</ul>
They both have mostly the same capabilities:
<ul>
<li>16 Channels</li>
<li>12-bit dimming (4096 levels of dimming!)</li>
<li>Daisy-chainable (connect multiple boards together - want 96 PWM outputs? 6 boards.)</li>
</ul>
However, the TI TLC5940 while popular has a crucial flaw - its PWM channels act as a [I]current sink</em> (negative or ground), and not a [I]current source </em>(positive).
The LDD-H PWM input requires a positive voltage of up to 6V DC, with a current source providing 0.1mA - a tiny amount, but still it needs to come from a [I]current source</em> and not a [I]current sink</em>.
The PCA9685 [I]can</em> provide the same capability as the TLC5940, and its PWM outputs can provide up to 10mA of current per pin - perfect!
It also has a PWM frequency of up to 1000 Hz / 1kHz - lights flicker at 60 Hz, so at 1000Hz the dimming will be super super smooth, in combination of 4096 levels of dimming.
You'll be able to dim at 1% without flickering.
TL;DR:
I'm going to buy one of these [IMG]http://www.adafruit.com/products/815">Adafruit PCA9685</a> driver boards to use for driving the LDD-H drivers.
The Arduino will control the PCA9685 board, which will control the LDD-H drivers... and let there be light. :)
MagicJ;848014 wrote: Hi
Just joined so I could make a comment
My current project is very similar to yours, although I am using the standard 3w CREE leds and an Arduino MEGA.
For controlling the LDD's I also considered the TLC5940 and the PCA9685 - my preference was the TLC5940 primarily because it is readily available in a 'through the hole' version and it is cheap. I also have one of the Adafruit boards but it was around $16. In comparison, I can put together a TLC5940 circuit for less than $2.
Now, on my test bench I have been using the small low current led's which work fine. But, on stumbling across this thread I starting thinking that perhaps I should test it with an LDD and a 3w led.
Please note - I have no electronics training and, to be honest, I don't always fully understand why or how things work.
You are correct in stating that the TLC operates as a current sink but I have managed to get it too work.
If you connect the ground from the Arduino to the -ve terminal of the LDD board; and connect the output pin of the TLC to the PWM input of the LDD board it works, albeit the reverse of what you expect i.e. send 4096 to the TLC and the output is zero or send 0 to the TLC and the output is 100% - this reversal is easily adjusted for in the sketch.
I plan on trying to work out why it works (but it is probably beyond my level of knowledge) but it does work :thumbs:
Given the ease of working with the TLC5940 I thought you may be interested in this outcome.
Cheers
Welcome!
Yeah, basically with the TLC5940 what you're doing is driving the PWM signal down to ground on a High signal, and letting the PWM output "float" on a Low signal.
The LDD PWM input interprets this in reverse, so with the TLC5940 signal "High", it's going down to ground (~0V) instead of up to 3.3V or thereabouts.
As a result, your PWM duty cycle is reversed... Yes, you can work around that by re-mapping in code, but there are still some drawbacks there.
The PCA9685 has a "totem-pole" output - the PWM output pin is in between a totem-pole configuration of resistors/transistors, so it can provide current (source), or receive current (sink).
The TLC5940 can only sink current, so it technically can't provide any output current at all.
I have my on-going build thread
It's been about two month now with the new LEDs and my corals loves it
