Exercisebike with proportional LED light


At an exhibition (DSE) and a shareholder meeting, the danish engineering consultancy company COWI wanted to profile their energyefficient and environmentfriendly image. Therefore they wanted to construct a exercisebike with a generator that is connected to energyefficient LED illumination. The light intensity should be proportional to the amount of energy produced by the person on the bike. The more energy produced, the more intense light.

There should be made two different versions. One for the shareholder meeting emitting a green light, designed as an over-size-arkitect lamp (see picture to the right), and one for the DSE exhibition consisting of 7 warm white LED spots to illuminate the posters. COWI hired AKJ Inventions to make the control electronics for both versions.

For the arkitect lamp there were used 4 green Lamina Atlas LEDs. For the exhibition there were used 7 VS-P3 LED spots from Vossloh-Schwabe.
The control electronics were constructed on Veroboards due to the ultra short delivery time. The functionality is described here: The generator on the bike produces AC with an amplitude proportional to the rotations / amount of energy produced. The light intensity in the LEDs is dependent of the current though them. Therefore the control electronics measure the amplitude from the generator, and adjusts the current in the LEDs proportionally. So that the light intensity is proportional to the rotation speed of the pedals.

If you need help for development of a project like this or something different. Please feel free to contact Allan Krogh Jensen for a free offer.


Exhibited a the sharholder meeting of COWI. Photo by: Niels Brøchner


Control electronics
for the 7 LED spots