As the Arduino only supports 14 output digital pins, I ordered some shift registers a while back from eBay. They took 7 days to arrive but are finally here.

As a small project to get my feet wet with serial/parallel output, shift registers etc. I’ve set about building a 25 (5×5) RGB LED matrix display. I may extend it in the future to 7×5 for larger fonts.

I’m using circuit board from RadioShack to which I’m soldering the LEDs. I intend on using breadboard for the chips until I get the circuit figured out.

I have always struggled with my soldering skills. I could never get the solder to flow where I wanted. It just melts on the tip of the iron and gloms all over the place, everywhere but where I wanted it to go.

That all changed last night when I discovered what I think might be where I’ve been going wrong all this time. I’ve always heard that you heat the lead and let the solder flow onto it. That never worked for me. It just bubbles on the lead and "floats" over the pad.  I’ve also heard you should heat both the lead and the pad, but with that method I could never figure out how to position a chisel-head soldering iron to get them both hot enough.

So last night I tried heating the PAD with a "PENCIL" tipped iron. With this iron/method combo, the lead gets hot by default. After 2 seconds, the solder will flow like the wind and seems to gravitate around the lead, following the path of the pad.

So it took a while but last night I got 100 successful solder joints (25 LEDs, each with R,G,B and Cathode). Tonight I’ll bridge the pads and form a matrix circuit.

I am getting excited.

As a separate note; checkout this little browser add-on which enhances viewing images in things like Flickr, Picasa etc. [LINK], pretty cool.