The working principle behind HandEnergy is that of a two-axis rotor gyroscope. “You may be familiar with the wrist-training device called the Powerball, which is a powerful handheld gyroscope,” HandEnergy co-founder Alex Novik told Digital Trends. “We came up with the idea of putting a battery, metal coil and magnets inside a similar device for generating electricity. We spent a year developing it, trying to find the best materials we could. After around a dozen prototypes, we finally arrived at one that we were happy with.”  Read more…