Here's the original hackaday article that was referenced.

Very cool robogeek.

I bet its that expensive! A two layer board for 4 leds, plus 2 connectors per board! WOW! A tad bit of overkill.

Pardon my ignorance, but what are J1 and J2?

J1 and J2 look like spots for a 5 pin molex connector, one on each end, so they can be daisy chained as long as you like.

Two questions:
1. Why a double sided PCB? You have 4 lines and ground, and one led for each line going to ground. Getting a custom PCB ethed seems overkill. You could fit it all on a .5"x.6" piece of stripboard. You wouldn't even have to cut any of the traces.
2. Why two spots to attach the molex connectors? On the female (cable) molex connectors, crimp two wires for each connector, and use 90 degree posts for the male connector. viola, whole pcb package down to .5"x.5", and no expensive custom etching. As a bonus, if any of the molex conectors gets loose or disconnected, it won't disable the rest of the pieces further down the chain.

futurelec.com has large protoboards for $1.95. I counted up, and if you can work it on a 5 hole x 5 hole board, and can make clean cuts with your dremel, you can make 42 pieces out of each board. Even if you want tons of room nd go to 10x5, thats 21 pieces from a board that cost less that $2, instead of hundreds for etching.

I don't think they should all be in a row. like this .... they should probably be closely grouped to avoid separation of the colors like this :: or possibly the white in the middle and three tips like the benz symbol.

For reference:
Thanks for the props Jason.

I bet its that expensive! A: +
OVERKILL: +
uhh, 2 sided pcb why?:
*A couple things on this 2 sided PCB thing, one is I work for a Defense contractor and am used to building rugged High quality boards(as expensive as they may be... its why the toilet seat costs $5,000 and the hammer is $2,000). Also I design High Speed digital processing boards that rarely go below 10 layers so 2 is like nothing for me. also those 10 layer boards cost about $250 each in small quantities.
*Ok, that said if you go for at least the 2 layer board you get Plated Thru-holes this provides for a stronger solder joint and less likely hood that you will pull the pad off when soldering or during a pillow fight in your dorm room.
*Also, lets say you want to make a bunch of these and some of the controller boards the design that I am working on now.it will be a 2 layer board as well. You could order a prototype panel with a couple controller boards and a bunch of the led boards on it.
*Ah yes, and protoboards they are good for testing designs but if i am going to be displaying something or making alot of them then no I will not use a proto board. also most of my stuff is surface mount so i don't really think of them as viable alternatives.
*Needless to say no board I will design will be on a single layer, therefore its a moot point for me.

you need to consider:
Thanks for the tip, for 2 layer boards they look really good on the price - it would be 5 rows of 22 boards on a single panel for 110 for $89.

LED Placement:
Yes I considered those types of placments to be better I just wanted to stay within the brackets on the original design.

Robogeek

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