DIY Multichip LED Build

[leedoherty]

LDD-H, And I would use the 600's which is what I am going to use on my 50

Thanks will have a look and see if i can get them in the UK

[Zeuthen]

Thanks will have a look and see if i can get them in the UK

If you do find them for cheap, be sure to let me know - I'm in Denmark, so I'm looking for a supplier within the EU to avoid the steep tax handling fees charged by the danish postal service. So far, the cheapest I've found in the EU is from here, but it seems they don't carry the 600's. If nothing better comes up, I guess the 500's will do too.

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

[leedoherty]

If you do find them for cheap, be sure to let me know - I'm in Denmark, so I'm looking for a supplier within the EU to avoid the steep tax handling fees charged by the danish postal service. So far, the cheapest I've found in the EU is from here, but it seems they don't carry the 600's. If nothing better comes up, I guess the 500's will do too.

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

Hi i have found them for £7.90 each in the UK dont know if that is a good price or not
I would be interested in purchasing some of your PCB if you have to make a minimum order they sound like a really good idea

[leedoherty]

Hi i have found them for £7.90 each in the UK dont know if that is a good price or not
I would be interested in purchasing some of your PCB if you have to make a minimum order they sound like a really good idea

I have just requested a quote from meanwelldirect will let you know the price how many did you need ?
My mother lives in the USA i may be able to arrange to have them shipped from there
Lee

[Zeuthen]

Hi i have found them for £7.90 each in the UK dont know if that is a good price or not
I would be interested in purchasing some of your PCB if you have to make a minimum order they sound like a really good idea

Well, at AmaraLighting, they are £3.71 each. I've asked them if they can get the 600's for me.

Regarding the PCBs, I'll need to order a minimum of 10 and I'll probably use 4 of them myself (2 per dream chip), so if I don't ruin any, I'll have 6 left that I could send you if you cover the expenses. I should warn you, though, that this is the first time I ever designed a PCB, so success is not guaranteed. Under all circumstances, you'd have to wait until I've been successful in driving and dimming the dream chip with my setup - I wouldn't want to cause an expense on your behalf with something that doesn't work.

If you can't wait, I can post the Eagle files here, but then off course, you are on your own. I had a colleague review the schematic and the board layout, and as he said: you need a working prototype to be sure.

Best,
Esben

[Zeuthen]

I have just requested a quote from meanwelldirect will let you know the price how many did you need ?
My mother lives in the USA i may be able to arrange to have them shipped from there
Lee

If you get a good price I'd be interested. I'll need 11pcs - 5 per DC and one for backup.

Best,
Esben

[leedoherty]

I think you may have found the best price after shipping is taken into consideration I would love to try one of your boards let me know how you get on with them
Could we not use the 700 version and dim it down or am i been stupid ?
Just learning this electronics stuff have just got my jarduino working and ordered the temp sensors
Lee

[007Bond]

If you do find them for cheap, be sure to let me know - I'm in Denmark, so I'm looking for a supplier within the EU to avoid the steep tax handling fees charged by the danish postal service. So far, the cheapest I've found in the EU is from here, but it seems they don't carry the 600's. If nothing better comes up, I guess the 500's will do too.

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

Hi Esben... I'm planning on using the LDD's also. Are you going to post any pics when you start your build?---Rick

[reza]

Also interested in LDD's.

[Lasse]

Now the thread is working good

Sincerely Lasse

[Zeuthen]

Could we not use the 700 version and dim it down or am i been stupid ?

Yes, we could do that - but 700mA is the absolute maximum current for the 50 led, so if you fail to dim for some reason (software failure, bad connection, etc.), you go full power (if the failure causes the PWM pin of the LDD-H to go open circuit). This may result in overheating and damaging the dream chip or maybe even frying the corals. The best design choice would be to figure out just how much current you need to drive through each channel at max and then chose the matching driver one or two steps above that to allow for some tuning. If you really need 700mA you probably would have chosen the 100 led.

I haven't done the PAR math for the dream chip, but when I was considering a Cree led fixture, I figured I'd need about 120W of led lighting. If I go with 500mA that gives me about 30V x 0,5A/ch x 5ch = 75W per chip. With my two chips I can go to about 150W which probably will be enough even though the Epileds may not be as efficient as the Cree leds. If I get the 600's, I can go to, say 185W total. The reason to do that would be to have some headroom for tuning the spectrum. The headroom comes at a price though, because you need an AC/DC PSU capable of delivering at least the theoretical maximum power that your circuit is able to consume. High power PSU's tend to be more expensive. With the 700's I'd probably need a 250W AC/DC PSU to be on the safe side.

I'll put in some cheap, normally-off relays to let the Arduino switch input power for the LDD-H's. That way, if the Arduino goes out, so does the lights - which is probably what I want when the Arduino is offline e.g. for reprogramming. It does not protect against software failures, however (which is why we need to do thorough software testing).

The conclusion? You can use the 700's, but it is probably not the optimal choice for the 50 leds when considering durability/reliability, coral safety and total system cost.

Oh, by the way - I plan to use the TP-Link WR703N with OpenWRT (embedded Linux) to control the Arduino via wifi. That way it should be possible to reprogram the Arduino without even opening your stand, and you can have a web UI instead of the display shield that many people are using to interface with the Arduino. Also, the WR703N has NTP and a realtime clock, so you don't need to buy an RTC for the Arduino - just let the WR703N handle the high-level stuff and let the Arduino be its obedient slave.

Hmm, I'm straying from the subject now - better stop here

Best,
Esben

[Zeuthen]

Hi Esben... I'm planning on using the LDD's also. Are you going to post any pics when you start your build?---Rick

Yup - but it may be a while, because I am also doing a reef controller shield for the Arduino with headers for the dream chip drivers, sensor breakouts from Atlas scientific, temperature, and some other stuff. I'd like to include both boards in the same order to IteadStudio.

Best,
Esben

[Lasse]

@Zeuthen

I have done some calculation which currents will be optimal for different channels at the 50 LED chip. I have done them with base of my measurements of my 100 LED chip. I am away from home for a couple of days but I will post them on Sunday.

Sincerely Lasse

And keep on posting

[007Bond]

Yup - but it may be a while, because I am also doing a reef controller shield for the Arduino with headers for the dream chip drivers, sensor breakouts from Atlas scientific, temperature, and some other stuff. I'd like to include both boards in the same order to IteadStudio.

Best,
Esben

Sounds real cool Esben, I'll be watching for it here on SDR.---Rick

[jsjonesrdh]

Lasse,

Would you mind linking me an example of what type of 100k pot I should be looking into? Again I will be using a HLN-80H-36B driver.
Thank you,
Justin