Nuts and Volts - September 2014

Well … There’s one tiny downside. When I say tiny, I mean that the IC is only available as a surface-mount device. WorldSemi used to offer the WS2801 IC in a through-hole DIP package, but stopped a few years back. Why they did this, I have no idea. It seems like the perfect hobbyist LED controller, except for this one tiny problem.

Soldering the IC isn’t actually horrible, to be honest.

I’ve soldered a lot smaller ICs. Soldering SMD components isn’t much harder than through-hole components. It’s just a bit different. You’ll need a few other tools in addition to the ones you already have — a smaller tip, a smaller diameter of solder, a bottle of flux, and a magnifying lens (10x Loupe) — in order to check if you soldered everything correctly. There’s a good nine minute video on You Tube that shows how to solder SMD components at http://youtu.be/3NN7UGWYmBY.

Think of it this way. You probably already wished that you knew how to solder SMD components but didn’t have a good excuse to do so. Now’s your chance to learn a new skill! A lot of powerful ICs are available in an SMD package only, so this new found skill will give you an even greater list of components to choose from. (Do I sound like a politician yet? Okay, I’ll stop.)

The circuit for the LED controller is fairly straightforward: 12V is converted to 5V with a simple zener diode. The WS2801 doesn’t need as much current as the RaspPi. Power for the LED strip is turned on or off with an NPN transistor. It’s easier to switch off ground than the +12V needed to power the LED strip. The LED strips are connected to a terminal block that is labeled for