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
FIGURE12. LED
controller schematic.
FIGURE13. FinishedLED controller PCB.
LED Controller 1 LED Controller 2
LED Controller 3
1
234
5
6
1
432
5
6
1
2
3
45
6 FIGURE 14. Animated
display channel
numbers.
50 September 2014