The team connected an antenna to a temperature sensor, placed it close to a Wi-Fi router and measured the resulting voltages in the device and for how long it can operate on the remote power source alone.

Even more ambitiously, the team also connected a camera to their antenna. It was a low-power sensor capable of producing 174 x 144 pixel black and white images, which requires 10.4 milliJoules of energy per picture.

To store energy, they attached a low leakage capacitor to the camera which activates when the capacitor is charged and continues operating until the voltage drops to 2.4 Volts.

The images were stored in a 64 KB random access memory (RAM). In the subsequent tests, the camera performed remarkably well.

By adding a rechargeable battery, he increased the distance to seven metres. The router could even power the camera through a brick wall, demonstrating that it would be possible to attach the device outside while keeping the power supply inside.