Tank Journal Archive

[MagicJ]

LedGroupBuy have recently started making a 100w multi-LED chip - see http://www.ledgroupbuy.com/lumia-5-1-100w-full-spectrum-5-channel-led/ for details.

I thought it might be fun to try one of these over the pool - they are designed to cover a 60cm x 60cm area but by raising it a bit I can easily cover the pool.

It incorporates 50 LED's in 5 individually addressable channels including:

Channel 1 - Neutral White (base white spectrum) (36V @ 700mA)
Channel 2 - Royal Blue (base blue spectrum) (36V @ 700mA)
Channel 3 - Hyper Violet (enhanced growth) (38V @ 700mA)
Channel 4 - Deep Red / Turquoise (enhanced color spectrum) (32V @ 700mA)
Channel 5 - True Violet / Cool Blue (enhanced growth and color spectrum) (38V @ 700mA)

At around $110 AUD they are not exactly cheap but given the number of LED's they incorporate it's probably not too bad.

This gives you an idea of the size

I don't really like the way the wires were bent around in the packaging - it is now difficult to get them straight and the tab where they join onto the main body does not look like it would take a lot of bending.

I know that this will generate quite a lot of heat so some sort of active cooling will be required - I am not sure if it will be enough but I am going to start with a CPU heatsink and fan that I extracted from an old computer today

Fits nicely with a generous amount of Arctic Allumina to fix the chip to the heatsink

Now to organise some wiring and fire it up - if you see a glow in the Southern sky then you will know that I got it going :p

 

[chimaera]

Awesome! Can't wait to see this in action.

Though from the builds I have seen Stateside you might need a bigger heatsink ...

 

[Sam Parker]

This is interesting, keen to see how it pans out.
Sam

 

[MagicJ]

Managed to find a few hours this afternoon to get this going - started by running the strings at 500mA.

Though from the builds I have seen Stateside you might need a bigger heatsink ...

You are correct :eek

This thing puts a huge amount of heat out of the front of the chip let alone the back. Definitely lots of light but the heatsink quickly gets too hot to touch, even with the fan running.

I have just been reading through a few other build threads and I think I might try something like this

It will take a few weeks for this to arrive so it looks like my MH will need to stay in place for a while yet.

 

[chimaera]

That looks cool! Yeah I had seen people using 12" Makers Heatsinks because 6" wasn't enough - I guess when you think about it, 50 LEDs in a square inch ...

 

[MagicJ]

I was reading a thread where they thought that a 6" Makers would have been OK :confused:

My heatsink/fan was definitely too small - the picture above is stated to be OK for a 100w LED chip although coming from a Chinese eBay store I am not so sure.

Anyway, I will try this and see how it goes.

 

[MTG]

hey shane what about an intel cpu cooler? should be able to pick those up preaty easily and can usualy dissipate 80w-100w of heat fine!

 

[MagicJ]

hey shane what about an intel cpu cooler? should be able to pick those up preaty easily and can usualy dissipate 80w-100w of heat fine!

That's what I started with - admittedly it was a fairly old one and a bit smaller than the modern day equivalent.

 

[MTG]

that little one you were using wasnt that a north bridge cooler?

 

[MagicJ]

that little one you were using wasnt that a north bridge cooler?

No - it was an old CPU cooler. It was out of one of my old computers that dad has been using for a few years - not sure what the CPU was but I am guessing it was an early Pentium - maybe from around 2000.

 

[Sam Parker]

Wouldn't use that, it'd be an antique now! :p

 

[MagicJ]

Wouldn't use that, it'd be an antique now! :p

Does that mean it is worth a lot of money :rolleyes I am prepared to sell it, along with the motherboard, a 3.5" floppy disk drive (I have a 5.25" as well which I will throw in), a 33.6k modem and a few other must have add-in boards.

 

[Sam Parker]

to the right crowd, you'd make a handy bit of coin (not exactly retirement funds though!). Retro is cool these days!

 

[MTG]

My media centre pc has 1000x the power of that
Shane if you want a heatssink pay for postage and ill send u one from work

 

[MTG]

CPU heatssink and fan that is

 

[MagicJ]

My media centre pc has 1000x the power of that
Shane if you want a heatssink pay for postage and ill send u one from work

Thanks Matt - mine arrived in the mail today :)

 

[Sam Parker]

Be sure to give us some updated pics and a review once you have it sorted.

 

[MagicJ]

Still playing with this one. Hooked it up to the new heatsink but the copper core was too small for the base of this LED chip. The heat coming off the front was massive - I defnitely need something with a bit more mass than these CPU heatsinks me thinks.

 

[Sam Parker]

hook it up to an STC-1000 for a heater circuit and stuttery light effects!

 

[MagicJ]

I have managed to get this to a position where it works but I do need to look at some better heatsinking. The heatsink/fan combo pictured above is hollow through the centre - I fixed a thin piece of aluminium across the hole in an attempt to spread the heat to the fins, and fixed the LED onto this aluminium. It works to a certain degree but I really need some meatier heatsink directly behind the LED. For now I am only driving the channels at 350/500 mA although they can be driven up to 700mA. Whilst the fins of the heatsink are cool, there is a fair amount of heat coming off the front of the chip which is not good.

Anyway, here are some pictures of the various channels (these were all driven at 700mA and there has been no colour correction) - I used my clown fish tank for these pictures rather than the pool

Channel 1 - 10 x Neutral White

Channel 2 - 10 x Royal Blue

Channel 3 - 10 x Hyper Violet

Channel 4 - 5 x Deep Red + 5 x Turquoise

Channel 5 - 5 x True Violet + 5 x Cool Blue

Channel 1 + Channel 2

Channel 1 + Channel 2 + Channel 3

All Channels @ 100%

Channel 1 @ 90% + All Other Channels @ 100%

The chip worked nicely with the Meanwell LDD's and my Arduino LED controller. The choice of LED's is pretty much the same as I use anyway and the fact that they are so close together means that there is no colour banding at all - I like the overall colour balance.

I was not very happy with the way the wires were bent in a circular fashion for shipping as they have proven impossible to straighten out but that is only a minor issue. Overall, I think that these are an easy way to get 7 LED colours over your tank.