The idea is that a blind person uses a navigation app, and can query to see “what is around”. In the list of beacons that are around, they can tap the one they want to know the location of and it will start to produce an audible signal for a short time.

The BLE module is configured as an iBeacon and allows connections. It has a battery service and an “Immediate Alert” (AKA “Find me”) service.

Patrick used the following to build the prototype:

• A 550 mAh 3.2 V LiFePO4 cell
• A #LiFePO4wered/Solar1 prototype to charge the battery
• A 5.5V, 0.6W monocrystalline solar cell
• A Silicon Labs (formerly BlueGiga) BLE113 module
• A beeper that works very badly (better solution needed)
• And a IP65 enclosure

xorbit has shared the booster for loud piezo beeper on OSH Park:

PiezoBoost