High Density Matrix on the Cheap!
I got addicted to playing with FastLED after making up an Ambilight clone for my OpenElec media pc & my TV. Unfortunately though work has been slow for me this last year so money is tight.
After using 30 LEDs/m for the Ambilight, I got some 60 LEDs/m to make up a 15x15 and then a 68x7 matrix. It was fiddly getting the strips spaced right for even spacing between LEDs and of course I had to adjust all the 50cm joins as the LEDs didn’t line up. Of course I would have loved to start buying the 144/m but find the cost is just way to expensive and am slightlyconcerned that the vertical spacing would be bigger than the horizontal…
Anyway, I had noticed that they sold single LED boards on Aliexpress a while ago, but recently I came across these round boards that came in 10x10 grids ready for you to snap apart, and better still they were only $18 with free shipping! Perfect for me as UK customs have a personal duty free allowance of £15, my last shipment from SparkFun of $28 had £9 handling and duty added!
Of course I knew it would require some soldering to hook up, just didn’t really think about how much though! 420 joints later I could test the matrix out. I have another 5 individual shipments in the post and intend to hook them together when they arrive :-/
Anyway, just thought this might be an option for other people, who like me have the time but not the money, and want to get an LED density of 106 LEDs/m with perfectly even X/Y spacing.
Can you post a link?
Oh that’s cute. But my god you’re making your life hard for yourself 
Here is a link for the current listing @Dave_Morgan
http://www.aliexpress.com/item/100x-WS2812B-LED-With-Heatsink-10mm-3mm-DC5V-5050-SMD-RGB-WS2811-IC-Built-in/1396752191.html
Their usual price is $20 but every other day or so they have 8-10% off, like today
@Robert_Atkins Yes, it is hard work, but I have the time and using the single solid core of stripped down telephone cable makes the power rails quite easy 
Besides, FastLED is an addiction, this will be my third matrix without any clear use, my friends think I’m mad!
Interested to see how you go with power there too, btw. I’d tried the method you’re using (daisy-chaining the power to every row, only injecting it at one point) and I found it really didn’t work well, though this was on a much bigger matrix (32x18). You’ll pull 6A with that one on full-bore? Meh, pretty easy then
I am intending to connect 8 boards to make a 10x80 matrix and will connect the “power rails” across all 8 boards. I will probably use 1.5mm solid core for the power injection at the ends and possibly in the middle.
I was surprised by the even brightness when testing the above board as I had only used the single 0.4mm for power!
The chips have constant current drivers embedded, so it won’t be an issue of brightness; what’ll happen is you’ll get voltage drop over the length of the power bus and the LEDs furthest away from where the power is injected will be “redder” (actually less blue). You’ll also pull more amps than you planned and your thin gauge wires will melt.
Thanks for the link Aaron, I’ve ordered some (I’m in the UK too), I’ve been wanting something like this for a while.