An invention by Mina Danesh brings the use of autonomous wireless transmitters a step closer. For her dissertation, she built an antenna incorporated into a solar cell of a small autonomous wireless system for the first time.
The applications of autonomous wireless systems are numerous; for example, in order to measure the fluid pressure of the eye an autonomous wireless system would be more than a welcome invention. Of course, there should be no wires attached to the eye, but making such a system autonomous and wireless is tricky, because it needs to be very small and powered on its own.
Mina Danesh (microelectronics) made a fascinating design. For the first time she incorporated an antenna into a solar cell for a wireless sensor node. “In this way we could reduce the costs and halve the size of the systems, which could be as small as a few mm3 and eventually be implemented at the nano scale, because we no longer need a separate antenna and solar cell for smart wireless systems,” she explains
A photovoltaic cell harvests light and uses this to create a current at a certain voltage in order to get the system working. Because it is also an antenna, it could receive and transmit data to other wireless devices or a hub that collects data – a smart combination. For both the photovoltaic cells and the antenna sticking out, this is the best way to harvest sunlight and transmit and receive information.
Danesh’ autonomous smart systems make use of a rechargeable battery or a supercapacitor that is capable of storing energy. “When there is no light, the system could keep on working thanks to the storage devices,” Danesh says.
How much energy the battery should store depends on what it is used for. Measuring the fluid pressure of the eye is only one possible application. It could also be used for wireless keyboards, to monitor the pressure of tires or for agricultural purposes, by measuring the soil humidity. “Several wireless systems could then interact with each other over a distance of 50 meters for example and share information,” says Danesh, who invented three kinds of systems: a system with one solar cell, a second with two solar cells, and a third with a flexible solar module. “It depends on the application what system could be used best. The flexible one could be worn as a bracelet and measure the pulse.”
She opens a small box with the impressive three small systems inside. They are a couple of centimetres long and wide. She built them herself and emphasizes that they could be made a lot smaller. She also gave them poetic names: Smart Lollipop, Dipole Wings and Loop Flexo.
On May 8, Danesh will defend her thesis. A number of companies and universities have already shown their interest. Danesh: “Companies working in partnership with the University of Wageningen think the system could be used for agricultural purposes, for example. Other companies that make medical and space applications were enthusiastic as well. I therefore have high hopes that this smart system will be used in the near future.” (RV)
Comments are closed.