Finding users in a wireless sensor network and exchanging messages through wearable badges

In a sensor network composed of several plugs distributed along the Media Lab, a person wearing a wireless badge should be able to find another person who is also wearing a badge in a fast and easy way. These badges would allow the exchange of messages between users as well.

An LCD display would be the main interface between the user and the badge. It could display the list of users and allow you to find the person you want to talk to. A list of pre-defined frequent messages such as:

Are you in your office now?

• Could you come to my office now?
• We are having a meeting now…
• Give me a call.
• …

could be stored in the badge. In the future, we would like to be able to send voice messages through the badges and customize the messages you can send.

Once you select the person you want to talk to, a list of options would be displayed:

1. Find person
2. Send message
3. …

If you select option (1) the network should be able to locate the person and display its location in your badge.

If you select option (2) you would be able to send a pre-defined message to the person or group of people you selected.

Other options could be easily added.

How to know the location of a user?

Each badge will have a unique identifier associated with its user, and each plug will have a unique identifier associated with a location.

Each plug should be able to know its neighbors (other plugs, and wearable badges). How can we find the plug that is closest to a wearable badge? By looking at the received signal strength coming from different plugs and wearable nodes.

How to send a message?

By selecting the message and pressing a button on the badge. In the future you would be able to say a voice command and send voice messages.

Another idea is to display in my plug's LED display in which office I am as I move around the lab. Usually when you want to talk to somebody in the lab, it is common to go to the person's office without being certain if the person is actually going to be there. Once you get there, if the person was not in her office you could look at the LED display to see whether she is in the lab or not and where she is.

Hardware

Each wearable badge would need to have:

• 1 mini-board with microcontroller and wireless transceiver
• 2 push-buttons (yes/no, accept/decline, scroll up/down…)
• 1 push-button (turn on/turn off device, tracking mode…)
• LCD Display (user interface).
• LCD Driver
• In the future they should also have
• 1 microphone
• 1 speaker
• 1 accelerometer

Software

Everything would be programmed directly on the microcontroller.

If a PC user's interface is available you could customize the list of messages and users.