Monday, July 03, 2006

Power your Ipod by walking

Student harnesses ‘soler’ power

AN enterprising student has invented an environmentally friendly form of "soler" power to recharge her mobile phone.
Tracy Robertson, 34, from Aberdeen, who is studying for a BSc Honours in design for industry, has created a shoe insole that contains a battery charger powered by walking or jogging.
The average person produces 100W of electricity a day and Ms Robertson decided to harness this power.
The E-sole, is on display at Gray's School of Art degree show. Ms Robertson said: "It is very small and I believe it could be built in by a trainer manufacturer."
AN enterprising student has invented an environmentally friendly form of "soler" power to recharge her mobile phone.
Tracy Robertson, 34, from Aberdeen, who is studying for a BSc Honours in design for industry, has created a shoe insole that contains a battery charger powered by walking or jogging.
The average person produces 100W of electricity a day and Ms Robertson decided to harness this power.
The E-sole, is on display at Gray's School of Art degree show. Ms Robertson said: "It is very small and I believe it could be built in by a trainer manufacturer."

Via (The Herald)

1 comment:

Chris said...

It makes no sense to say someone produces "100W" per day. To start with, Watts are a measure of power, i.e. work done (energy) per second. The correct units should be Joules (J). If someone generated 100W continuously, this would amount to 100*60*60*24 = 8.64 MJ. Convert this to Calories by dividing by 4.2 = 2 million Calories! Since the average person eats about 2,500 Calories in a day, this is clearly impossible. In addition, the amount of energy converted by the insole will clearly depend on how it works. Piezoelectric methods are extremely inefficient - converting about 1% of the mechanical energy put in. Mechanical methods (using some sort of alternator) are better, but take up too much space. I would like to see how Ms. Robertson tackled the problem. I confess I am sceptical that it is possible. There have been many such reports in the last few years (e.g. Trevor Bayliss of clockwork radio fame who claimed to charge a mobile walking in the Namibian desert), but we never hear anything more after the initial media stories. I fear we are being misled by self-publicity and bad science.