If you're a Nokia phone user and you go on some long bike rides, there's a bike-mounted phone charger coming out this year. It's intended for developing countries where people still get around by bike a lot. At $36 it seems a bit high priced for developing countries, but what do I know.
Providing free and environmentally friendly electricity for mobile phones, the Nokia Bicycle Charger Kit consists of a charger and dynamo, as well as a holder to secure the phone to the bike. When the kit is installed, the dynamo - a small electrical generator - uses the movement of the wheels to charge the handset through the standard 2mm charging jack used in most Nokia mobile phones.
This is not a new idea. Here's a BBC article about two enterprising students in Kenya:
Jeremiah Murimi, 24, and Pascal Katana, 22, said they wanted their dynamo-powered "smart charger" to help people without electricity in rural areas.
It is estimated that some 17.5 million people out of Kenya's 38.5 million population own a mobile handset - up from 200,000 in 2000.
Although similar devices already exist in other countries, they are not available in Kenya.
The two electrical engineering students from Nairobi University have been working on their own invention, which they are selling for 350 Kenyan shillings ($4.50) each, over the last few months during their university break.
One thought that occurs to me is that the Kenyan students are a good example of necessity being the mother of invention. Plus, they are reusing and repurposing materials. In our toss-it-when-it-breaks-cuz-I-can-always-buy-a-new-one society they would be considered hobbyists.