Bicycle Assisted Cinema

We held a successful first as part of the big green fortnight, a showing of the film “In Transition 1.0”, powered entirely from solar/cycle-generated source stored in a leisure battery. The session was held in the community room at the Hamworthy Firestation. Despite hopes of burly firemen to pedal the film, this mostly fell to Ian, Andy and John.

Ian powers up the battery before the film

Ian powers up the battery before the film

 

John explained that he had very carefully selected the term Power Assisted Film.

To invert the electricity from 12v DC to 24oV AC, and run a laptop and projector he calculated needs 322 Watts of power. This may not sound like much more than a couple of incandescent lightbulbs, but that takes quite a lot.

The mechanism uses the motor off an electric scooter, two rollers, and a contraption to hold any adult mountain bike in place. To reduce noise and improve contact, he had fitted a slick road tyre to the back wheel of the mountain bike used.

A single cyclist is probably capable of generating between 40-70/80Watts for a sustained length of time. Thus it would need a minimum of 4 cycles to power the cinema without storing the energy in a battery (or the lights going dim).

There is a group in London, Magnificent revolutions who run an outdoor cinema, using 8 bikes running at the same time. Instead, John opted for a pre-charged battery – solar and bicycle powered. However, he confessed to having tested the whole film earlier in the day, only then realising he had 3 hours to recharge the battery. Andy stepped into the saddle to top up the charge for the second part of the film.

Around 15 people attended. After the film, Andy highlighted some of the elements of Transition that are being undertaken in Poole and the surrounding area, and we had a general chat over coffee whilst several people took the opportunity to recharge the battery.

Well done to John for putting the kit together, and for getting a picture in the Echo with a real fireman earlier in the day, and to Harriet and John for organising the event.

Andy Hadley

 

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