Imec, TNO, and Cartamundi have developed a low-cost way of letting tags communicate with embedded devices wirelessly by using a capacitive touchscreen’s electronics rather than a dedicated RF protocol such as NFC.
With what the group calls C-touch, tags can connect to a device or through it to the internet by bringing them into contact with a touchscreen. The tag design described in the journal Nature Electronics uses thin-film transistor technology and is powered either by a thin-film battery or using a thin-film photovoltaic cell to harvest light from the touchscreen.
The prototype tag achieves data-transfer rates up to 36bit/s and is compatible with commercially available touchscreen devices without requiring hardware modifications. The flexible thin-film integrated circuit has a 0.8cm<sup>2</sup> on-chip monolithic antenna and dissipates only 38nW of power at 600mV supply voltage.
“Our C-touch tag paves the way to a multitude of new applications compared to standard RFID or NFC solutions as it takes advantage of the widespread availability of touchscreen readers compared to the limited amount of NFC readers,” says Kris Myny, principal scientist and R&D team leader at Imec. “We are testing the tag system and communication method using a range of different touchscreens from a variety of brands, including Apple, Samsung and Huawei.”
Prashant Agrawal, program manager for thin film electronics at Imec, added: “Our next steps will be to further improve the performance of the tags, enable new features such as bidirectional communication with touchscreens, and work with companies in developing solutions based on C-touch tags in different application domains”, says
Steven Nietvelt, CTO of Cartamundi says the company sees applications in the design of games: “The C-touch tags will enable us to even further blur the boundaries between digital and physical gaming.”