Open Access Control - Power Board with UPS

Thanks to Martin Wood from the hackerspaces.org mailing list, we have a v1.0 circuit for the UPS/Power supply board. I decided to break this out into a separate board so that it is optional. The basic circuit floats a 12V sealed lead acid battery at around 13.5V, and uses this as the regulated output for sensors and door locks.

Also, it looks like MOVs (metal oxide varistors) are the way to go for clamping the voltage spikes from a door-holding magnet.