Cree LED DIY PWM Controller Build - HELP!

Hi

First time posting on here but been thu a few (lots!) threads over the past weeks!

I have just started out in saltwater (couple of months now) (long time with freshwater) so learning alot quickly!

So far so good. All perams correct and stable! 2 clowns and 2 bangai cardinals going stong. A few hermits (blue and red legged) a turbo snail and a conch (+ a load of stars and tiny snails ect that came on the live rock).

My tank is a 95L 30cm deep x 34cm high x 80cm long (25 US Gallon) with a 50L Sump (12ish US Gallons) with 10ish KG's of live rock and a skimmer.

I am building an LED light rig for my tank which i aim to have sunrise/set and moon phases ect powered from my Raspberry pi (small, single board computer with GPIO).

I have got my parts from Rapid LED shipped to the UK (cheaper then getting them here!!!). ---Just a few bits first to play around with and make sure i can get it to work before shelling out £'s

Cart Items Qty Item Price Item Total​

Solderless CREE XP-G Cool White LED Wire Length: 6"
$4.25​

Solderless LED Plug
$0.75​

Solderless CREE XT-E Royal Blue LED Wire Length: 6"
$3.50​

CREE XP-G R5 5W Cool White LED with 40°, 60°, or 80° degree Lens Lens Color: Black
Lens Width: 80 Degree
$5.00​

CREE XT-E Royal Blue LED with 40°, 60°, or 80° degree Lens Lens Color: Black
Lens Width: 80 Degree
$4.25​

Royal Blue Moonlight LED
$2.50​

Subtotal: $20.25
Grand Total: $20.25​

Anyways to my questions!!! (please go easy on me!!!)

First question is how many LED's do you think I need? I'm working on between 15-20 cree's but not sure. And what colours (white, royal blue ect) and in what split.

So my big problem is building the LED driver.

I dont want to spend $30 + shipping on a driver when i'm going to need a few. I have found some DIY jobs online. But cant for the life of me work out what values i need the resistors to be! I read the guide a few times now and am none the wiser!

Heres the guide i'm trying to follow:

a little micro makes all the difference

Looking to buy the parts from Farnell or maybe RS as Maplin doesnt have the bits i need.

Any help would be awsome

I did find this one also but not sure if it would work or how to control it by PWM:

http://www.instructables.com/id/Super-simple-high-power-LED-driver/

Again any and all help would be brilliant!
Thanks
DemonsRun

 

You have nano<10-15 medium power leds should be enough< ask rapidled they give tou advise

 

Thanks will give them a shout!

Any ideas on the PWM Driver?