Device 'key'

It is possible that I would want to restrict usage of the device, and to do this I would need some kind of 'key'.

I'd like to have a physical key which would 'unlock' the main device. There is an option for password entry and other types of security, and these will all be user tested to find the most suitable for the discovered context of use.

One option is to build a 'key'using a 'reed switch'. A reed switch opens or closes when subjected to a magnetic field. This resource provides further information: click here. A key could be built with a magnet in it, which when placed upon the right place in the device, would allow interaction with the device. This simple 'key' device would only be able to have tangible protection applied to it: where the holder of the key would have to physically protect it. It is also easily duplicable. However, unless a system hacker knows is told how the key operates, it could be fairly difficult to work out unless they are technically experienced. Because of the system which is being protected, i have assessed that extensive security probably does not need to be applied to the key. There is the concern that any physical key, no matter how complex, can always be stolen, so why not make it a simple system. With a password system, the user could be observed so there are risks with all types of systems.

A reed switch like this one could be used: click here.

Below are google sketchup models of the system. The magnet could be placed in almost anything, for example a keyring. Anything magnetic will work. This could be utilised by users: if they lose their keyring they could know that a fridge magnet would work.

Fig 1

The reed switch is built into the arm of the chair (bottom left).

Fig 2

The reed switch embedded into a transparent case (for illustrative purposes only). The thicker the casing, the less sensitive the sensor. There are different levels of sensitivity.

Fig 3

Hovering the magnetic key chain over the embedded reed switch would activate the system. The most likely way for this system to work would be for it to be necessary for the keys to be left on the device throughout the interaction.