For years, many scientists have tried to use ambient radio waves to use them as a source of energy for small devices . The problem is that the power they use is very low, and the device has to have a minimal consumption for that to work. Now a group of scientists has created a chip that can convert WiFi wireless signals into electrical power to power a small LED, as well as other small devices and sensors.
To do this, the new chip uses what are called torque oscillators, or spin-torque oscillators (STOs) . The first ones were created very recently, and are capable of generating microwaves, although with a very weak signal. Therefore, some scientists tried to put several on the same chip to obtain more power, but with the problem that they have not been able to determine the best configuration to make it more efficient, with problems around the space between them and a low frequency response .
Eight STOs connected in series illuminate one LED
However, the researchers seem to have found the key using eight STOs connected in series . With this, they were able to use the 2.4 GHz waves of the WiFi and convert them into signals with direct voltage. By running them through a capacitor, they can cause a 1.6 volt LED to light up. Charging the capacitor for 5 seconds allows the LED to offer light for a minute, even after they disconnected the WiFi.
The researchers affirm that what has called them to invent this type of systems is that most of the WiFi waves around us are wasted, and with this at least the energy can be used when it is not being used to offer light or make them work small sensors. Thanks to this, the need to use batteries in sensors such as thermometers or similar is reduced, with capacitors that are much cheaper.
They will add more STO to the system
The team says they will continue to advance their research into this system by adding more STO to the setup. With this, they could have more energy to illuminate larger LEDs, and even to operate devices that require a little more power. They will also test the power harvesters to charge devices wirelessly, also helping to have a wireless network without interference.
This wireless charging is even more useful, as today’s power system requires a constant source of electrical signals. If the charge is done wirelessly to a battery , the amount of energy that can be harnessed is greater, as well as making the duration also increase. At the moment it is a prototype, but if it really works that well, it will be a matter of a short time before these systems reach the market, although there is a long way to go before they work, for example with a wireless hard disk.
