Fri 15 April 2011
I've not had a lot of time to go at electronics in the past while (mainly a combination of work things and family things kicking my ass), but I got to some of it tonight -- The clever parts of the design and build are basically done, so what's left is producing the final piece.
Aside from the motion sensor parts, there's also the bright light, to mess with people's night vision. For this, I got 4 super-bright LEDs, and did monstrous things with solder to produce a 5x2 header, that was fully connected along the long side. This gave me the 4 LEDs connected in parallell. This is pretty bright with the 5v applied from the analog output of the Arduino:
The final result will be built on an Arduno Fio board, which only has a 3.3v signal (It's powered off a 3.7v LiPo battery), so I'll need to amplify that somehow. I'm thinking I might try to power the board and LEDs off a regular 9V instead, or have the LiPo powering the board and the 9V powering the buzzer and leds, gated on the signal line of the board with some transistors. I may be of course talking out my ass. I'm going to pick up some various transistors over the weekend and experimenting. My guess is the gate and emitter of a transistor need a common ground, which won't work with using separate power sources. We'll see.
Of course, deadlines, help. I'm supposed to be using this thing next saturday. So, full steam ahead.