Hand crank technology seems to be incorporated into almost any portable product large enough to take the mechanism at the moment and as it gets more efficient we’re able to power these toys for longer and longer without ever having the need for batteries.
We’ve been interested for a while in its use in portable shortwave radios so here is a run down on how the system works and some of the latest radios using the potentially ever lasting hand crank technology.
How Do Hand Crank Radios Work
In its most basic form when the hand crank on the radio is turned it produces power by spinning a very small generator, this power is then applied to a rechargeable battery that is used to power the radio. As long as the hand crank produces power and the battery can still hold a charge then there will never be any need to worry about these radios running out of juice.
Its important to note that the radio that started the whole thing off was the Freeplay invented by Trevor Baylis which didn’t actually have any batteries at all and produced power by storing mechanical energy in the form of a spring to turn the generator and applying power directly to the radios circuits.
Battery technology was a whole different world back then without the small, super efficient NiMH (Nickel Metal Hydride) and Li-ion (Lithium Ion) fitted in all the modern portable devices we use daily.
Once this mechanical energy was used the radio had to be cranked up again, this system would produce enough useable power for a very basic radio but the use of a rechargeable battery allows more power hungry features and a longer operating time for a given amount of cranking.
The Addition of Solar Power
Another technology that has got more efficient is solar power with an amazing decrease in the size of solar panels to deliver a useable amount of current and its no surprise that this has also been incorporated into portable shortwave radios alongside the hand crank system giving these products an added option for being powered by renewable energy.
Latest Hand Crank Shortwave Radios
With a whole range of features the new hand crank powered radios are a far cry from the original Freeplay radio.
The Kaito model shown here has the normal AM, FM, and LW as well as 2300khz to 23mhz HF band coverage along with digital tuning and a large L.C.D display.
As with many new radios of this type the solar charging option is there on top of the hand crank along with the ability to charge the NiMH batteries by more conventional means.
Batteries, solar panels and the hand crank mechanism itself are the main components that allow these radios to be operated indefinitely without having to be plugged into a mains supply. These important parts are only going to get more efficient as time goes by meaning a much longer operating time and many more features on the radios.
Freeplay windup radio photo courtesy Wikipedia