I can't find any details about how much power you can get with this. Let's try a back of the envelope calculation.<p>My WiFi router has probably 2W. If you put this device at 1m (3') and assume that the power is evenly distributed you get 2W/(4 pi 1m^2) = 0.16 W/m^2. Let's assume that the surface of this device is 10cmx10cm (4''x4'') (quite big for a small device) and it's perfectly perpendicular, you get 0.16 W/m^2 x (.1m x .1m) = 0.0016W = 1.6 mW (and this calculation is quite optimistic, because it assumes no loss in the transmission and in the conversion or storage)<p>A typical LED has 30 mW (or more), so this is not enough to keep it light. Perhaps blink it once every 20 seconds.<p>And if the device is further away, it's worst. The calculation assumes that the distance is 1m (3'), with 2m (7') the power is reduced x4.<p>In the web page they show a fire detection device with a nice led that, so I'm not sure that they can collect enough power to blink the led. The surveillance camera is completely out of discussion, specially if it has a motor.
This is somewhat like the demo I've seen of florescent lights working under high-power transmission lines without connection.<p>Interesting our bodies absorb all that energy every day without lots of cancer. Actually, there is lots of cancer.