Proximity Maintenance Device

For my first 7 in 7 project I created a prototype for a proximity maintenance device. This is a radio-enabled bracelet or necklace worn by two individuals who do not want to become separated in a crowd. As long as the devices can maintain radio contact, nothing happens. However if the individuals move far enough apart or lose radio contact, their devices begin vibrating. At this point they can seek each other out and reunite.

The prototype I made uses XBee radios paired with Arduino microcontrollers to manage the radio messages and produce the alerts. The challenge of a 7 in 7 project is to complete it in 24 hours, therefore these devices are still in a fairly rough state. Luckily they are fully operational and can easily be worn outside for real-world testing. Thanks to Kate for helping with a quickie sleeve mount and cool sealed vibrator motors with magnetic mounting snaps. One project down, six to go!