At the beginning of the week I was out of projects and I needed something to design, so I built this simple device. It utilizes a sound impact sensor and a custom relay driver (transistor based) that can drive the 12V lamp with a 3V microcontroller.
It uses a P8X (Propeller Chip) running at 80Mhz on a breadboard (for easy mods) and enabled with a relay controlled by a transistor. The transistor circuit will come in handy later, and the relay circuit will be used in a future project. The P8X is really much overkill, as all it is doing is switching, an SX chip could handle it just fine and maybe even that would be an overkill. The program only uses about 250 bytes out of the 32,000 that are on the chip.
It worked great and the relay circuit switched with perfection. However, it didn't prove itself useful enough to survive more then a day when it was salvaged and labeled as experimental only. It used 2 regulators and a crystal, which I am low on and with the large project I am starting I needed them greatly. Nevertheless, I still have the program, which is the heart of the device and I have the schematics so I can eventully build it back correctly. It is one of the few times that I documented everything.