The rise of radio, TV, cellular, Wi-Fi and other wireless technology has flooded the world with extra electromagnetic signals, and that trend is only going to continue. Those signals represent a lot of energy to broadcast.
At the same time, while wireless technology lets us carry our gadgets everywhere, slow progress in battery technology means we still need to recharge our gadgets every day, or carry around a heavy brick. When it comes to smaller, low-powered sensors and gadgets, the biggest part is often the battery.
Researchers from the Sensor Systems Lab at the University of Washington have realized that these two problems might actually be one solution. Their answer is to power gadgets using Wi-Fi.
It turns out that a Wi-Fi signal is strong enough to power some types of electronics. In their first attempt, the researchers managed to power a temperature sensor and a battery-less surveillance camera using only Wi-Fi at a dozen feet away.
Of course, there were some hurdles, and biggest is that Wi-Fi signals are actually kind of spotty. Wi-Fi runs in fits and starts as it sends and receives data. Also, there might be more or fewer Wi-Fi hotspots running in a given area and on multiple frequency channels.
To fix this problem, researchers programmed their hotspot to broadcast static when it wasn't actually sending data. They say this didn't hurt the Wi-Fi data speed at all.
Even with the full-power broadcast, it took 35 minutes of Wi-Fi exposure for the camera to charge enough for a single shot. Not something you'd want for a DSLR, but for periodic surveillance it isn't too terrible. However, for a less power-intensive sensor, Wi-Fi is enough to keep it running continually.
Of course, you could combine a gadget with a battery and a Wi-Fi charger. So your phone might be charging when you're out and about. Wi-Fi power might only be enough to keep it from draining the battery while in standby mode, but that could still extend your battery life quite a bit.
I'm looking forward to seeing what comes of this new technology. In the meantime, make sure that your Wi-Fi isn't putting you danger. Lock down your Wi-Fi against criminals and nosy neighbors today.