The Ooono Co-Driver warns of dangerous spots as well as speed cameras / speed traps visually and acoustically and all fully automatically. Below is a video with a detailed explanation, setup, functionality and a brief comparison with the Blitzer.de app.
Connection: Bluetooth 4.2
Smartphone: iOS & Android
Battery lasts: 30.000 km. / ~ 1 Year
Warnings: LED & Visual Warnings