Devices created using high-volume, large-area, manufacturing techniques are increasingly in need of a power source which doesn’t compromise the low cost, thin and flexible, nature of these printed devices. Coin cell batteries are a common choice due to their relatively low cost, however they can significantly increase the overall size of a printed device and their rigid form factor can reduce or negate the flexibility of the device. Flexipower is a printed energy harvesting system that can capture energy from a nearby radio frequency (RF) energy source using a printed or part-printed design. The use of printing technology will enable the devices to retain their low price and thin flexible form factor and eliminate the need for primary batteries in a wide range of applications.
• to develop architectures and processes to print RF energy harvesting components
• to develop high-volume processes to integrate these components into a thin flexible system to enable low-cost manufacturing
- The project developed a number of demonstrators incorporating printed circuitry and a range of conventional components (e.g. LEDs and ICs). Hybrid printed and conventional circuits dramatically reduce costs and allow for novel designs.
- One device design, based on a bespoke 500kHz transmitter, demonstrated the maximum possible short range (<10cm) energy transfer - providing enough power to light up dozens of LEDs.
- A second device design, utilising the 13.56MHz RFID frequency present in most smartphones, operated over a similar range, with lower powers. The transmitters are already owned by many people.
- A third design system was demonstrated for the UHF RFID standard, transmitting smaller amounts of power but with a potential maximum range of 1m.
The footage shows the energy that a smartphone puts out. Every time the phone searches for an RFID tag, that energy is harvested by this printed system and is used to power a conventional light emitting diode.