We've completed the TTL controlled power switch and that seems like a pretty useful project by itself. Of course we had to hack the hack and redesign Chris Reilly's implementation to suit our needs and the parts we had on hand. We roughed out the design on paper. As great as CAD is, nothing beats a sheet of quad paper, a mechanical pencil, and a big eraser for your first few design iterations.
Next I went to a big box home supply store - there are no more hardware stores in our neighborhood - and found parts such as a junction box, a power socket and a cable clamp. Since it wasn't exactly what I needed, yet another design iteration was called for. The result was this:
And on the outside it looks like this. The cable plugs into the wall and that powers up the outlet on top. We'll plug the power supply for our microcontroller into that outlet. The microcontroller's ground, 5V power, and signal lines will plug into the connector on the left. The amber LED on top indicates 5V power. The red LED indicates that the signal line is high, and that the outlet on the bottom should be energized.
In the next installment I'll write about the microcontroller and sensors.
