Splashpower – Wireless Power for Wireless Devices
The second technology uses an acoustic signal (ultrasonic) to excite a piezoelectric crystal which converts acoustic energy into electrical energy. According to patent 6,737, 789 a piezoelectric device along with a transformer (to increase the output voltage), and a rectifier (to create a single polarity) can generate electrical outputs based on a mechanical (in this case an acoustic wave) input.
The challenge with both technologies is that the device to be charged must be within close proximity of the charging device. So while the device to be charged is not actually connected to the charger, it’s not too far from it. The technology is in its early stage and could become viable if the distance from the charger to the device were increased.