ICEdot Crash Sensor
$149, plus annual service subscription
The ICEdot Crash Sensor will mount onto any helmet. When paired with the ICEdot app on a smart phone, the system is able to detect motion, changes in forces and impacts.
In the event of critical forces, the device triggers the app over low-energy Bluetooth to sound an alarm and initiate an emergency countdown. Unless the countdown clock is stopped, the app will then notify your emergency contacts and send GPS coordinates of the incident so that appropriate follow up actions can be taken.
Currently the Crash Sensor app is available for iPhone 4S and 5. An Android version will be released soon for phones utilizing the new Android 4.3
To keep your phone charged, consider a dynamo hub with a USB charging port. The
B&M Luxos U combines a dynamo headlight (with daytime running lights) with a handlebar-mounted USB charging port. Charge your phone or your Garmin as you ride. I just put one on my primary commuter. Although I don't use USB devices, it's a great headlight. I like the DRLs.