The front wheel of the bicycle provides power for a dynamo. This is transferred to a charger which it gives it to the phone.
The actually charging begins when the speed hits 6 km/h.
On average, 10 minutes by bicycle with a speed of 10 km per hour phone provides enough energy for 28 minutes of talk or 37 hours standby.
The phone’s upload speed is directly proportional to the speed on walking on bicycle.
The Nokia Bicycle Charger Kit will cost about $18 and it will be available in stores this year.
Nokia Bicycle Charger Kit:
-Dynamo: 40.5 x 94.5 mm
-Charger: 70 x 34 x 21 mm
-Phone holder: 142 x 22 x 24 mm
-Connecting cables: 500 mm + 375 mm (from charger to dynamo), 350 mm (from charger to phone)
-Dynamo (with mountings): 250 g
-Dynamo (excluding brackets): 190 g
-Charger: 36 g
-Phone holder: 11.5 g
Here is the list of compatible phones with this charger.
Image source: Nokia