Solar panel-equipped ski helmet uses sunlight to power its communications system
By Ben Coxworth
March 6, 2012
It looks like the skiers' communications systems from Buhel and Recon could soon be in for some solar-powered competition. Working with German tech company TEXSYS and the Technische Universität Berlin, researchers from the Fraunhofer Institute for Reliability and Microintegration have developed a communications module that can be integrated directly into a ski helmet. That module is powered by nothing but sunlight, and can be linked with the user's mobile devices via a Bluetooth-enabled glove-based control unit.
The communications module consists of stereo speakers built into the inside of the helmet, a microphone incorporated into the chin strap, and a Bluetooth transmission/reception unit. A curved solar panel built into the top of the helmet charges an integrated lithium-polymer battery, which in turn delivers power to all the electronics.
Creating a functioning solar panel that follows the curved surface of a ski helmet, however, isn't as simple as it might sound. While thin, flexible solar cells certainly do exist, they can only be bent in one direction - in other words, you can roll them into a cylinder, but not into a dome. Additionally, they are typically less efficient than rigid cells.
To overcome this challenge, the Fraunhofer team divided monocrystalline silicon solar cells into tiny individual chips. In this way, not only could they be spread over the helmet's domed surface, but they were also less susceptible to damage from mechanical stress than larger cells would be. Additionally, in the event that one or more of the chip cells does fail, it won't affect the operation of the rest of the chips in the panel.
Another challenge involved the cold weather experienced by skiers, as it is typically very difficult to charge batteries at below-freezing temperatures. A proprietary microcontroller, however, reportedly allows the module's battery to charge at temperatures between -30ºC (-22ºF) and 60ºC (140ºF). Should the temperature fall outside of that range, the communications system can still draw power directly from the solar cells - assuming there's sufficient sunlight at the time.
The control glove has simple button controls that can be operated with gloved fingers, and a large OLED display. It will allow users to perform tasks such as making and receiving phone calls, or operating a Bluetooth-linked music player. Should one of those external devices run out of juice, they can be recharged from the helmet's battery.
Needless to say, skiers also have the rather outrageous option of simply not taking phone calls or listening to music while they're on the slopes.
A prototype helmet has already been built, and Fraunhofer is now working with a major helmet manufacturer to create a limited commercial run, which should be available towards the end of this year for a price of about EUR300 (US$393) each. The modules will also be available on their own for under EUR100 ($131), and could be incorporated into a variety of helmet types, such as those used by motorcycle riders.