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Alternative energy news, and information about renewable energy technologies.

Dec 28

Pedal Power Dynapod

Posted in Human Power | Pedal Power

African Maize GrinderA dynapod is a stationary pedal-powered device. The word ‘Dynapod’ comes from the Greek words for power and foot. The dynapod can be attached to any kind of device or tool and used to generate power for a multitude of activities. The first design for this type of unit was introduced in 1968.

Although it was not built, Alex Weir (Edinburgh University) built one and two person dynapods at Dar-es-Salaam in Tanzania. An cement-filled bicycle wheel was used as a flywheel. He developed and built many prototype units using square tubing for the framework. His prototype inventions were tested as corn grinders and a winnowing machine.

Commercial Maize ShellerThere are seemingly endless possibilities for pedal power tools. The list is long: Hand-driven machines, grinders, forge blowers, pumps, pottery wheels and drilling machines are just a few. The image to the left shows a commercial maize sheller, powered by a bolt-on dynapod unit. This particular unit can shell two maize cobs at one time, and has been sold in some African countries. The work is done by a heavy cast-iron fan, which acts as both a winnower to clear away husks, and a flywheel.

Dynapod PrototypeWhile pedal power is a great form of generating torque, there are some problems. Cyclic torque is one problem, another is rigidity. The pull of the chain can be as much as twice the rider’s weight, so a sturdy strut is needed between the driving and driven chain (see prototype image at right). The chain must also have some sort of adjustment mechanism in order to take up the slack. An obvious necessity is the need to keep the operator cool while they are pedaling. The Chinese use a simple canopy to protect the person from sun and rain. A small portion of the power generated could also be used to power a small cooling fan.

Source: Pedal Power News


McCullagh, James C., ed. Pedal Power: In Work, Leisure, and Transportation. Emmaus: Rodale Press, 1977. ISBN: 0-87857-178-7

  • Chuck

    While it is a cool toy and might be nice for those that are in a very remote area this does not “save” any energy.

    Since a person has to eat to keep the body system up the more you use it the more food you have to eat. Food has to be grown, processed, transported to a wholesaler, transported to a retailer, kept in controlled climate environments if it is perishable, and then picked up by the consumer. The more we eat the more that goes into production.

    I ride my bicycle all over. I don’t save any money as I eat about twice what I did when I didn’t ride my bike.

    The advantages for me are less traffic headaches and no fees for going to the gym after work since I am in great shape.

    I am not under any illusions that I am “saving the planet” by riding my bike.

  • admin

    You are however, not expelling any harmful emissions!

  • Chele

    There are these things, called “gardens”…from which food is grown and eaten fresh, rather than using energy to over-process nutrients from the food and allowing it to sit in a big box store until someone decides to buy it.

    And while the average small family garden may not “save the planet”, it sure does go a long way in helping keep our Earth green…especially when we use other ‘green’ methods to save energy and use less resources.

  • pedal power student

    Thousands of people go to the gym everyday and use machines that waste energy and eat more after. Using pedal powered bikes or biking for transportation allows someone to exercise and generate energy at the same time. I exercise regularly and do not increase my food consumption significantly.

  • Paul Barden

    Would love to develop your idea in the workplace.

  • Mike C


    Check out our video of a bike powered slingshot kicking field goals!

    This is part of a class project, and our grade ONLY depends on how many hits we get, so please take a look.

  • Vilas

    The fitness freaks use excercycle, treadmill which can be used to generate electricity to charge battery of the Inverter for home lighting.

  • steph

    Pedal Power is alive and taking over here in Barcelona.. follow the link and join the party…

  • judy

    Why are they not incorporating this in schools under the desks, where the kids don’t get enough exercise? the power could be used to power lights, or there computers depending on the power they generated.

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