DIY led panel - again

[edd07]

Not a bad rule of thumb, but just thought it was worth mentioning

I've seen threads where people have used the same rule and bought a significantly more expensive PSU than was required, but if not sure, always go for more power - another good rule of thumb

Tim

Not a bad rule of thumb, but just thought it was worth mentioning

I've seen threads where people have used the same rule and bought a significantly more expensive PSU than was required, but if not sure, always go for more power - another good rule of thumb

Tim

I decided for two different lamps a blue ones with 30 xte and a red one with three different wavelenght, 620nm - 660 nm - 730 nm.

The power reuired bye the diodes is about 95w full power, i think a will get a 120 or 150 W PSU, for future additions, and because the it e decent price, about 35€, a 48v one. It is also because i'm going to use the same psu for both the lamps, and the red one should use 20% more power.

i already ordered the cree xt-e royal blue, 575mW bin, already on pcb (aluminium star). I'm looking for the 3 LDD 1000H online, it usually costs more than it should.

I'm looking for a good aluminium heatsink, but i still don't know how the market.

The effect should be like this http://forum.buildmyled.com/index.php?attachments/purple-comparison-jpg.206/

 

[edd07]

Hi guys!
Today arrived my 30 Cree XT-E Royal blue! They are really small! Wonderful!
This evening i'm going to shot some photo to show you. PSU and LDD have been shipped, and are coming directly to my home :3

-I've gone for a Meanwell RS 150-48, since i'm driving 10 LED in series, 3 series.
Here are the specs:
http://www.meanwell.com/search/RS-150/RS-150-spec.pdf

-Here are the LDD 1000H, 3, one for each string of LED.
http://www.meanwell.com/search/LDD-H/LDD-H-spec.pdf

-I've searched a long time for a good heatsink with a proper low cost, and the choice has fallen into this heatsink, with a 0.34 °C/W of thermal resistance.
http://www.farnell.com/datasheets/22486.pdf
It will be probably used with a 140mm fan, or maybe with natural ventilation.

-Here is the thermal glue
http://www.farnell.com/datasheets/1728852.pdf



-I'm still looking for a good PWM controller that work on a 48V circuit. Do you have any suggestion?
I don't want a sophisticated device, I'd prefer just a simple circuit with a potentiometer.
Do you think this will work?
http://www.ebay.it/itm/Pulse-Width-...8347?pt=Altro_Informatica&hash=item3cdcbb45ab

 

[perkint]

I think that'd work, but I'd still go for an arduino and a pot' personally

Tim

 

[edd07]

Yes, it should be very useful, but my arduino board is already busy with a thermometer LoL, and is a bit unstable in my humble opinion, due to variation of air ionization and other common phenomen. I don't trust to use it with an expensive LED bin xD

Are there any other options?

 

[perkint]

There are lots of people using them and commercial products based on them! They are stable enough, and even if it fails - it is only controlling the brightness of the light - your LDDs make sure the LEDs don't get too much current, irrespective of what signal it gets from the arduino.

But, other options? I would think the one you have picked it a reasonable example. Personally I'd trust the arduino more!

Tim

 

[perkint]

Oh, and an arduino is cheaper

Tim

 

[edd07]

Hum you put a bug im my ear. I don't know what to do. Arduino should be powered by its owm and is quite large, but it is more versatile and easy programmable. On thr other hand a ready made circuit is just waiting for connection to work.

Are there any integrated that can do this work?

 

[perkint]

Not sure about an IC that would do the job, but as to the arduinos size - have you looked an the nano pro?

Tim

 

[edd07]

Ok, gone, i'm designing the circuit with the arduino board soldered on a prototype pcb.

The problem now is:

I've got a 48V PSU. This PSU has to power at the same time:
-LEDs (48V)
-Arduino(5V)
-A cooling fan (7V)

Now, i'd need two DC to DC transformer, i think, connected in parallel to the PSU.
So i should have the LED circuit, the fan circuit, the arduino circuit all connected in parallel to the PSU. Could it work like this?

 

[easternlethal]

Use one of these to knock 48v down to 12v for the arduino.. it's almost the same size as an LDD.

The parallel circuit should work, at least I hope so because I am doing the same thing for my new controller. If you want to be safe just add some fuses to each circuit. I have one more circuit which connects a relay to my pump so I can switch that off too.

http://uk.rs-online.com/web/p/isolated-dc-dc-converters/7553605/

 

[edd07]

Shouldn't Arduino work on a 5.5v circuit?
i found this
http://www.farnell.com/datasheets/1750806.pdf

 

[easternlethal]

The atmega ic in the arduino takes 5v but the arduino board can take 12v or even more. http://playground.arduino.cc/Learning/WhatAdapter and it's better to step down to 12 rather than 5. more efficient and more options for dc-dc converters.

The murata converter looks good too.

 

[edd07]

Hum, ok, i didn't know it! It's better. I think i'm going to buy just one DC adapter @ 12v, and connect in parallel both arduino and the fan (that can work also @ 12v). It should be ok, isn't it?

Thanks!!

 

[jayball]

The effect should be like this http://forum.buildmyled.com/index.php?attachments/purple-comparison-jpg.206/

Just a fyi, those strips run more than just red and blue:
from BML:
LED Selections per 12" Board: (6) 450nm Royal Blue, (4) 405nm UV, (3) 6500K Cool White, (2) 625nm Red

They are also not meant as a stand alone light, but a supplimental spectrum

a 1:1 ration of red to royal blue is going to look more magenta than deep purple.

 

[edd07]

Just a fyi, those strips run more than just red and blue:
from BML:
LED Selections per 12" Board: (6) 450nm Royal Blue, (4) 405nm UV, (3) 6500K Cool White, (2) 625nm Red

They are also not meant as a stand alone light, but a supplimental spectrum

a 1:1 ration of red to royal blue is going to look more magenta than deep purple.

The original idea was to make one light in fullspectrum. I then decided to build two different lamps: a full blue lamp and a red / far red one. The white light usually comes from common home bulbs.

 

[perkint]

The voltage you need for the arduino depends which on you have. Some have an onboard regulator to step down to 5V but others (like the nano) don't.

Tim

 

[edd07]

Finally, i am going to dismount the temp circuit, and make arduino do few more thing.
The project is to build 3 different circuit:

-PWM controller
-Ambient thermometer
-Led/heatsink thermometer and eventually dim to 0 if the temp gets too high to avoid LED burning.

I've got an Arduino Uno board, now powerd with an ipad charger through usb cable.
I'm buying a 12v DC to DC adapter but i'm not sure about the current.
First temp sensor drain 50mA,
Second temp sensor drain 50mA,
PWM signal comes out at max 50mA,
Fan drains 350mA.

My PSU provides max 3.3A @48V. In parallel I should sum amperage, so assuming that LDD max needs 1A, I'm afraid to exceed the remaining 0.3A.

 

[easternlethal]

or you can just get a second 12v psu to run the non led circuits. If they all run at 12v you might even be able to find a wall plug to do it. Then you don't need the dc-dc converter.

 

[edd07]

Yes, it is simplier xD I also have it yet. It make me able to add 10 more LED later too.

As promised, even if a bit late, here are LEDs and the PSU!

I can see the PSU have got 2 Vin + and 2 Vin- pin, does anyone know why?
And do you think that it will remain quite cool if i put it near to the LED heatsink?

Here are LEDs!
They are really tiny!! McPCB looks quite good even if it is aluminium.

Opps, sorry, i didn't think that site was out in the forum, here are the images.

 

[perkint]

You bought LED bloke LEDs? Good man! You sure the stars are Aluminium? I know a lot of his (certainly all the ones I have with his branding) are copper! Top quality

The PSUs have multiple output connections just to make life easier if you want to run multiple things from them.

Tim