Automate your home without rewiring [Resources_Hands On

Abstract

I don't like working in the dark. But I also don't like mains current. Maybe it's the smoke and flames, maybe it's the flying droplets of molten metal, maybe it's the chance of sudden death, but I just like to make my mistakes at lower voltages and amperages. So years ago, when I found out that all the light fixtures and most of the sockets in my basement (where I have my workbench) were on the same circuit, I put my plans for converting everything to remote control on indefinite hold. · But lately I've been exploring more mechanical solutions: If I can't play with the power lines, why not just use microcontrollers and servos to push buttons, pull lightbulb chains, and flip switches directly? · It started at the office space in downtown Montpelier, Vt., that I share with a couple of dozen other freelancers and small entrepreneurs. There's an intercom-buzzer setup for letting people in, but no one likes interrupting a coding spree or a conference call to walk over to answer the door. So I thought it would be easy and fun to build a widget that would push the door button remotely while avoiding any landlord trouble that could come from monkeying around with the intercom system itself. · Several prototypes later, I'd learned some valuable lessons. First, solenoids are expensive and power hungry and can push a button effectively only if they're mounted to within a fraction of a millimeter of their ideal position–too close in and you risk crushing the button into its housing; too far out and the button won't depress far enough to register.