Mitsumi Unveils Details of 'Battery-less Wireless Switch'

Mar 1, 2010 04:54 Tsunenori Tomioka, Nikkei Monozukuri

Mitsumi Electric Co Ltd prototyped a wireless switch that is for lighting equipment and incorporates a power generating mechanism at Mitsumi Show 2010, the company's technological exhibition.

Mitsumi showcased the switch, which it calls the "battery-less wireless switch," at CEATEC JAPAN 2009, which took place from Oct 6 to 10, 2009, in Chiba Prefecture, Japan. But, at that time, the company revealed only that its power generating mechanism is an electromagnetic induction type.

This time, Mitsumi disclosed that the power generating mechanism is actually a generator. And it exhibited a down-scaled battery-less wireless switch.

The generator has the same structure as a permanent magnet (PM) stepping motor. Its diameter is 25 x 8mm. The permanent magnet and the coil were tuned to enhance the power generation efficiency though the company did not reveal the details.

In the battery-less wireless switch, the generator is rotated by utilizing 3.5mm linear movement that is caused when the switch is operated, generating several milliwatts of power, Mitsumi said.

By using the power thus generated, radio signals in the 2.4GHz band are emitted from the radio frequency (RF) transmitter module to communicate with lighting equipment's controller unit (wireless module) incorporating (1) a microcontroller that is used to turn on and off the lighting equipment and change the color of the light, (2) the power supply unit and (3) the RF receiving module. The controller unit is connected to the lighting equipment via a cable.

The battery-less wireless switch can be used not only for lighting equipment but for opening and closing a garage shutter and, potentially, for keyless switches for vehicles, Mitsumi said.

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