Ideally, the Sensing Beds are two full-size beds in different locations. Each bed would have a grid of 12 pressure sensors located under the mattress pad to track the location of the sleeper as well as a microcontroller wirelessly transmitting the position data to another microcontroller located near an Ethernet jack. That microcontroller sends the data over the Internet to the other location. There, a microcontroller near an Ethernet jack transmits the position data (again using RF) to an X10 controller that turns on the appropriate heating pads under the mattress pad in the second bed.

Why so many different components?
In a lab, we can count on having an Ethernet jack nearby our installation. However, our homes are a different matter. Unless there's a wireless home network, Internet connectivity is usually far away from the bed. Until the day normal houses are covered with a cloud of connectivity (or data moves over powerlines), transferring data from one communications network (the Internet) to another (the home wiring system) will remain troublesome. Hence the project's modular - and wireless - design. Sending data over the home wiring using the X10 protocol also lets us avoid nasty accidents with relays and hacked-up AC power cords.

The benches
Equipping two beds with full sensor networks and heating pads proved to be impractical. Given X10's limitations as a home networking solution, ITP's wiring simply could not accommodate the number of devices per circuit required. Instead, we chose to prototype the Sensing Beds on a pair of benches in ITP's lounge.

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