3D printing provides home automation enthusiasts with the tools that they can use to build custom cases, brackets, gears, and other tools for their systems. The following links cover 3D printers and 3D printing services:
Makerbot 3D printers: http://www.makerbot.com/
Thingiverse: http://www.thingiverse.com/
Shapeways 3D printing on demand: http://www.shapeways.com/
Stratasys 3D printers: http://www.stratasys.com/
i.materialise: http://i.materialise.com/
Next Engine 3D scanner: http://www.nextengine.com/
David 3D scanner: http://www.david-laserscanner.com/
Here is a list of miscellaneous resources based on some of the topics touched upon in this book, and other areas of interest:
Popular mechanics back issues at Google Books: http://books.google.com/books?id=49gDAAAAMBAJ&source=gbs_all_issues_r&cad=1&atm_aiy=1960#all_issues_anchor
Wikipedia article on mains electricity: http://en.wikipedia.org/wiki/Mains_electricity
Wikipedia article on relays: http://en.wikipedia.org/wiki/Relay
Wikibooks content on embedded systems: http://en.wikibooks.org/wiki/Embedded_Systems
Open Source Initiative: http://opensource.org/