DIY Multichip LED Build

[Lasse]

I´m not a "pot" expert , but I think that you can use any one that can handle 0-100 K. The ones I've seen have 3 connections. Connect the middle to dim +. One of the other connects to dim -. Which you use does not matter - it only determines which way you should turn the knob to get maximum or minimum. Probably can someone else here, who is familiar with the US market, help you to pick up and link to a specific one.

Sincerely Lasse

[Screener]

As for the PCB's, I'm doing my own design in Eagle and I'll use the PCB prototyping service of ITeadStudio to produce it. I'll make it from two stacked PCBs, so the completed driver board will probably be a bit smaller than 2"x4"x1.5". I'll use screw terminals for power input/output and an RJ-45 connector for the 5 PWM channels. The remaining pins of the RJ-45 connected to a 3-pin header that can be used to connect a temperature sensor like the DS18B20.

Hopefully, I'll be able to hide the board within the fixture close to the heat sink. The fan will have its own 4-wire cable to the Arduino, so it is three cables (power, PWM+temp, fan) from the stand to each dream chip fixture.

Best,
Esben

This is what I'm looking for, for my LDD1000H's
When you are done Esben would you mind sharing the Eagle files?
If you need a US relay for your postal needs then I may be able to do that for you while we develop these ideas.

[Zeuthen]

This is what I'm looking for, for my LDD1000H's
When you are done Esben would you mind sharing the Eagle files?
If you need a US relay for your postal needs then I may be able to do that for you while we develop these ideas.

Thanks Screener for your kind offer. AmaraLighting say they can get the LDD-600H, so I probably won't need a relay for those.

I'll post the Eagle files for the driver board. Note that this design has not been tested, and I am not a professional electronics engineer, so I cannot guarantee that this design is applicable for any particular purpose. In other words: Use the information below at your own risk.

The driver board will have five LDD-H drivers, a header for a temperature sensor like the DS18B20, power screw terminals for input and output, and an RJ-45 connector that connects to the temperature header and the five PWM channels of the drivers.




To keep PCB price and footprint small, I've opted for a stackable design, so the PCB is designed to accept two different sets of components. The topside has three LDD-H and power in screw terminal. The bottom side has two LDD-H, the RJ-45 and the temperature header. The bottom side flips horizontically and attaches to the backside of the topside using the backside mounted pin headers for power and PWM. Female headers on one side and male headers on the other, of course.

Below, I've shown which components to mount on the top and bottom sides, respectively.



I plan to have it etched at ITeadStudio. The minimum order is 10 pieces, which is one of the reasons why I keep the PCB footprint as small as possible. This way, I can order a smaller PCB, and I'll only have 6 pieces left when I'm done - instead of 8.

Anyone interested in playing with the PCB design can download the Eagle files here:

Board
Schematic

If you spot any flaws in the design, feel free to post it here - any feedback is welcome, because I really would like this to work in the first attempt.

Best,
Esben

[Screener]

Esben this is awesome work.
I see you have pin headers/screw terminals and resistor for the thermometer chips.

Are you planning to have these boards close to yor LEDs?

If so will you also need
screw terminals for and pads for

1) fan solid state on off relay pin,
2) fan pwm pin
3) fan 12v, resistor, diode, ss relay, and transistor

The idea of sandwich is inspired!! I could stack 4 boards for 2 dream chips run in parallel. How's that!

[007Bond]

Ya Esben, nice! I have a question for you guys on the thermo chips. My build will have 4 DC's, so I will have one DS18B20 on each of the Zalman 8900 coolers I plan to use. Since all four DC's will have channels spread over each of the four cooler and if one cooler should over heat the DS18B20 on that cooler will interrupt the power to all four chips. My question is, how to find which cooler is having a overheat problem causing the DS18B20 to cut power to all chips?? I know that the DB18B20's have the ability to run many of them on a single line and they can be individually identified. Could the Arduino be programmed to identify which thermo chip is cutting the power to the Dream Chips? Thanks---Rick

[bobfish4blac]

sorry to change the subject, but I have a question I will be running 2 100 dream chips, running the white on one driver http://www.trcelectronics.com/Meanwe...150h-36b.shtml and the blues on another of the same driver, and for the antinic/UV http://www.trcelectronics.com/Meanwe...-80h-36b.shtml , I will be using a Dim4 contoller http://www.ledgroupbuy.com/dim4-4-po...ntroller-v1-0/ to dim the drivers but is it possible to add inline an 0-100 ohm resister to turn them down before the Dim4 so i have better contol of output.

Sorry if I am derailing the context here.

[Zeuthen]

Esben this is awesome work.
I see you have pin headers/screw terminals and resistor for the thermometer chips.

Yes - if you do run all your DS18B20 from a single Arduino pin, I'd put the pull-up transistor on the Arduino shield, though, because you'll only need one. With this design, you can do either.

Are you planning to have these boards close to yor LEDs?

If so will you also need
screw terminals for and pads for

1) fan solid state on off relay pin,
2) fan pwm pin
3) fan 12v, resistor, diode, ss relay, and transistor

I did consider putting a fan header on the driver board. Problem is I've used up all the wires in my ethernet cable for temp and PWM, so I need an extra cable for the fan, anyway. In this case I might as well do the fan control inside the stand and run a cable from it directly to the fan. Unless you have some other suggestion?

The idea of sandwich is inspired!! I could stack 4 boards for 2 dream chips run in parallel. How's that!

Not sure about stacking more than two boards - did you check the PWM traces? I guess you could use stacking headers for the input power and normal male/female headers to couple the PWM pair wise. A bit too late at night for me to think clearly now - I'll give it a spin tomorrow

Best,
Esben

[Zeuthen]

Ya Esben, nice! I have a question for you guys on the thermo chips. My build will have 4 DC's, so I will have one DS18B20 on each of the Zalman 8900 coolers I plan to use. Since all four DC's will have channels spread over each of the four cooler and if one cooler should over heat the DS18B20 on that cooler will interrupt the power to all four chips. My question is, how to find which cooler is having a overheat problem causing the DS18B20 to cut power to all chips?? I know that the DB18B20's have the ability to run many of them on a single line and they can be individually identified. Could the Arduino be programmed to identify which thermo chip is cutting the power to the Dream Chips? Thanks---Rick

It should be possible. How do you plan to trigger the power cut?

Best,
Esben

[007Bond]

Esben, not sure, originally I was planning on meanwell HLG series which dim with 1-10v signal and controlling them with a DIM4 controller. The DIM4 has on board 12v power terminals that go active when the controller comes on. You then add a optional relay that they use to control 110v power to the drivers. The main idea for the relay is to get the led's to total off since they won't dim to 0/total off. I was going to use a DS18B20 to interrupt the 12v relay thus shutting ower off to the HLG's. Now with LDD's and PWM I need to rethink. Most likely the same scenario, but as I said I would like to have a read out on the Arduino of which the four DS18B20 I would be using is shutting down power to the Dream Chips?? ---Rick

edit: rethinking I don't know if DS18B20's actually do switching, or are just signal. I'll need to look at them again. Originally I was going to use 70C Thermostat Temperature Switches http://www.ebay.com/itm/Thermostat-T...ain_0&hash=ite but I heard that in time they weld themselves together?

[Screener]

Yes - if you do run all your DS18B20 from a single Arduino pin, I'd put the pull-up transistor on the Arduino shield, though, because you'll only need one. With this design, you can do either.



I did consider putting a fan header on the driver board. Problem is I've used up all the wires in my ethernet cable for temp and PWM, so I need an extra cable for the fan, anyway. In this case I might as well do the fan control inside the stand and run a cable from it directly to the fan. Unless you have some other suggestion?



Not sure about stacking more than two boards - did you check the PWM traces? I guess you could use stacking headers for the input power and normal male/female headers to couple the PWM pair wise. A bit too late at night for me to think clearly now - I'll give it a spin tomorrow

Best,
Esben

I had thought about using cat5/6 plenum for the cable but I don't like the solid core twisted pair as it not really flexible enough, kinda kinky, where I move the lights out of the way for cleaning. That lead me to buy some multicore (12) stranded conductor audio cable. #71335K54. I think that would let me run the temp sensors in parasitic mode, bring 5 channels for PWM, power for LEDs and power for Fans and fan PWM all in one cable to the fixture above the tank.

Alternatively, I guess, 12v for the fans could be generated on the daughter board with a small DC-DC buck regulator, is that good alternative for you?

I really like the idea of the rj45 connector but since we rarely or never take these apart I'd be happy w RJ45 ( I guess 2), solder or screw terminals. Am I not correct in thinking I could pass through the stack the PWM wires, thermo wires and power traces through all the 4 stacked cards I'd need for 2 Dream Chips controlled in parallel. Having fan and temp control would really make the stack versatile In the light fixture enclosure and that would be.... satis-faction!

[Screener]

Esben, not sure, originally I was planning on meanwell HLG series which dim with 1-10v signal and controlling them with a DIM4 controller. The DIM4 has on board 12v power terminals that go active when the controller comes on. You then add a optional relay that they use to control 110v power to the drivers. The main idea for the relay is to get the led's to total off since they won't dim to 0/total off. I was going to use a DS18B20 to interrupt the 12v relay thus shutting ower off to the HLG's. Now with LDD's and PWM I need to rethink. Most likely the same scenario, but as I said I would like to have a read out on the Arduino of which the four DS18B20 I would be using is shutting down power to the Dream Chips?? ---Rick

edit: rethinking I don't know if DS18B20's actually do switching, or are just signal. I'll need to look at them again. Originally I was going to use 70C Thermostat Temperature Switches http://www.ebay.com/itm/Thermostat-T...ain_0&hash=ite but I heard that in time they weld themselves together?

If im right each temp sensor has a unique address that you could use to determine the ID of the overheating dream chip. How to deal with it is the problem. -- my suggestion, and others jump in if I'm not thinking logically ....

Well there is an on/off switch for the fans. If your fans derive power from the led driver dc power source with a dcdc buck regulator then coopting the fan on-off relay to turning on-off the Power to the LEDs would turn on-off fans in unison too. I cant imagine you would want high power leds on and fans off. This is why you might want to have a fan control function and ss-relay on your "Esben card" 5 channel stackable driver card. If you wanted to address many different fans/dream chip pendants then there is the problem of not enough arduino mega pins spare to do it. In that case there might just be enough pins left on the Arduino mega for a shift register mux to expand the fan on-off pin to multiple instances of on-off control for as many dream chimps as you have a need for. Of course this would need some programming (and a nice donation maybe).

That is, what I'm suggesting is have a on/off relay on the driver board at the dreamchip, drive the fans from their local led DC power source and when the arduino can identify an overheating dreamchip with its addressable temp chips, it could shut down only that dreamchip and it's fans together by using the mux addressable relay. Maybe you might want it to also sound an alarm and leave a flaming lightbulb icon on the default screen to warn you the fans or the heatsink of a pendant might need maintenance.

[Zeuthen]

I had thought about using cat5/6 plenum for the cable but I don't like the solid core twisted pair as it not really flexible enough, kinda kinky, where I move the lights out of the way for cleaning. That lead me to buy some multicore (12) stranded conductor audio cable. #71335K54. I think that would let me run the temp sensors in parasitic mode, bring 5 channels for PWM, power for LEDs and power for Fans and fan PWM all in one cable to the fixture above the tank.

I like the idea of running everything in a single cable. Did you check if the wire gauge is sufficient for the main LED power, and what is the cable diameter?

Alternatively, I guess, 12v for the fans could be generated on the daughter board with a small DC-DC buck regulator, is that good alternative for you?

The Arduino accepts 12V input, so I guess it would be easiest to just run the fans in parallel from the Arduino PSU. The Arduino PSU could very well be a DC-DC buck regulator connected to the main AC/DC PSU.

I really like the idea of the rj45 connector but since we rarely or never take these apart I'd be happy w RJ45 ( I guess 2), solder or screw terminals. Am I not correct in thinking I could pass through the stack the PWM wires, thermo wires and power traces through all the 4 stacked cards I'd need for 2 Dream Chips controlled in parallel. Having fan and temp control would really make the stack versatile In the light fixture enclosure and that would be.... satis-faction!

With a single 12-wire cable, I think the RJ-45 would be obsolete, and we should replace it with screw terminals - also saves us the crimping hassle for the male connector

As for the stacking, I've given it a bit of thought. I originally designed the board so that two PCBs would combine into one complete 5-channel driver - not for stacking multiple drivers together. With the current design, you can't do that, because only 3 PWM signals are transferred to the next PCB - the other two are directly connected to RJ-45. The reason I have 6 PWM pin headers in the current design is that it allows the boards to be flipped, connecting bottom-to-bottom. The motivation to stack was to keep the PCB footprint small and to save a bit on the PCB prototyping service at ITeadStudio. My two 50 led fixtures will be mounted with some space between them above a rimless tank, so I think in this case, separate drivers for each chip is adequate.

Stacking multiple drivers would make it easy to share PWM signals and power, which is a different design goal than the one I had in mind originally. This could be obtained by just adding another couple of PWM pin headers for the 2 PWM channels that are not transferred in the current design. Question is if the small PCB footprint makes any sense when stacking drivers? We could make a driver stackable version with a larger footprint, accommodating 5 LDD-H's on a single PCB, suitable for tank canopy mounting. Which option do you think would be better?

Best,
Esben

[Screener]

Oh yes, i see what you mean about the PWM pins not all stacking. and of course if you are having 2 separate fixtures stacking more than one set ( 2 PCBs ) is not necessary. I was planning 2 dream ships in one fixture over my 4'x2'x2' tank.

That cable i mentioned is 22 gauge, so good for 7 amps. It is the thinnest diam. I could find at about 0.22 inch. I also have stranded core 20 gage cable but it's ~0.46 inches diam. Kinda beefy but ok, still, it saves a lot of hassle and tangles with several separate cables. I think I'll use that.

I obtained a few 12v meanwell buck regulators just for that reason - simple to power arduino off the main PS. Deliver should be tomorrow. Mr. Jardin suggest this in the manual(bible), no?

While thinking about Bond's, James Bond's, question above - using a smaller 12V buck right on the led driver card with a relay as well would help those people who want to address individual fixtures with on off capability. That might be out of the scope for your card perhaps, but worth thinking about for someone wanting to kill two birds with one bullet. According to jarduino plan the fan relays have to go somewhere, I just thought the driver board as good a place as any.
But for me with 2 dream chips, I suppose, if a dream chip overheats (fan fail) turning them both dimmed to 0 would be acceptable if a warning was also given. I'd just do maintenance ASAP.

Anyway I do like the idea of one cable from the arduino, sharing the PWM signals and putting the driver PCB pairs all together in a sandwich stack so there is no wiring hassles at all between multiple controller sets. Just press together, et voila! There are already enough separate wires to cope with with all the chanels in a dream chip. Less is more!
I guess maintenance would be easier with your stacking idea too. Just pop them apart and replace the bad card. Since the drivers are pretty cheap it might be worth making a spare set right off the bat.

You are also right of course regarding size, adding a buck, fan/led relay, Diode and transistor and their related screw terminals to a set of top and bottom boards might just be too much for the small miniature format you had in mind. Would 5 drivers on a larger (but still stackable) single pcb board be more sensible if going this route? Do others think this arrangement would be usefull? Or am I over-thinking the problem.

[Lasse]

sorry to change the subject, but I have a question I will be running 2 100 dream chips, running the white on one driver http://www.trcelectronics.com/Meanwe...150h-36b.shtml and the blues on another of the same driver, and for the antinic/UV http://www.trcelectronics.com/Meanwe...-80h-36b.shtml , I will be using a Dim4 contoller http://www.ledgroupbuy.com/dim4-4-po...ntroller-v1-0/ to dim the drivers but is it possible to add inline an 0-100 ohm resister to turn them down before the Dim4 so i have better contol of output.

Sorry if I am derailing the context here.

You do not change the subject! The subject for this thread is DIY DreamChip build and it cover most of the issues.

To your question - I´m not sure that I understand what you mean. Can you explain in more detail?

Sincerely Lasse

[007Bond]

If im right each temp sensor has a unique address that you could use to determine the ID of the overheating dream chip. How to deal with it is the problem. -- my suggestion, and others jump in if I'm not thinking logically ....

Well there is an on/off switch for the fans. If your fans derive power from the led driver dc power source with a dcdc buck regulator then coopting the fan on-off relay to turning on-off the Power to the LEDs would turn on-off fans in unison too. I cant imagine you would want high power leds on and fans off. This is why you might want to have a fan control function and ss-relay on your "Esben card" 5 channel stackable driver card. If you wanted to address many different fans/dream chip pendants then there is the problem of not enough arduino mega pins spare to do it. In that case there might just be enough pins left on the Arduino mega for a shift register mux to expand the fan on-off pin to multiple instances of on-off control for as many dream chimps as you have a need for. Of course this would need some programming (and a nice donation maybe).

That is, what I'm suggesting is have a on/off relay on the driver board at the dreamchip, drive the fans from their local led DC power source and when the arduino can identify an overheating dreamchip with its addressable temp chips, it could shut down only that dreamchip and it's fans together by using the mux addressable relay. Maybe you might want it to also sound an alarm and leave a flaming lightbulb icon on the default screen to warn you the fans or the heatsink of a pendant might need maintenance.

Screener,...Thanks for the input. I'm nowhere close to a EE, but I do know some electrical. I'm just learning Arduino, so I usually need to read advice a few times and then use (my friend) Google to further understand the information.
Your last paragraph kind of sums up what I want to do.

what I'm suggesting is have a on/off relay on the driver board at the dreamchip, drive the fans from their local led DC power source I would assume I need to use a dcdc buck regulator as you stated. I'm not sure I will locate the driver board at the dreamchip. I was thinking of using multi-conductor cable also, back to a junction panel.

and when the arduino can identify an overheating dreamchip with its addressable temp chips, it could shut down only that dreamchip and it's fans together Yes, I would like the particular dreamchip to go off, but the fan to continue to cool


Maybe you might want it to also sound an alarm and leave a flaming lightbulb icon on the default screen to warn you the fans or the heatsink of a pendant might need maintenance. If I can have the Arduino stop power to the 5 LDD's of a problem dreamchip when alerted from a DS18B20 that would be sufficient enough of a warning. I had my original HLG thought/plan stuck in my head where I was going to drive all 4 DC with 5 HLG's so I would have needed to shut all 5 drivers off if one cooler was at overheat. This is the reason I was trying to have the DS18 show on the Arduino display which cooler was overheating.
With the LDD's now each DC will have 5 to itself, so only one DC will go off if overheated, which means I would not need to think about a mux relay now, not needing to identify individual DS18's---RICK