Thinfilm Electronics has successfully demonstrated the industry’s first printed electronic label to combine real time sensing and NFC functionality. The demonstration used an active (battery powered) label that reported ambient temperature to an NFC equipped smartphone. The smartphone can then log the alert automatically in a cloud database. Thinfilm hopes to deliver commercial samples to partners in 2015.
When the label exceeded a temperature threshold on a ceramic hotplate, its status report changed to state that the limit had been exceeded. The smartphone received a red status screen when the hotplate reached 35’C. The demonstration was presented by Thinfilm CEO Davor Sutija at the LOPEC conference for the printed electronics industry.
The demonstration comes four months after Thinfilm acquired Kovio Inc.’s printed-dopant polysilicon (PDPS) technology. The PDPS equipment allows engineers to use high-performance transistors capable of supporting the high-frequency RF circuitry needed for NFC communication.
The process allows fully printed or a hybrid design to be made, which incorporates more conventional surface mounted sensors in the label. Sutija said ‘Thinfilm has created a highly versatile, multi-sensor platform that is capable of addressing a range of needs our partners and clients may have. Temperature sensing is an area we initially targeted given the market opportunity and demand, but the market has also expressed significant interest in applications that measure time, humidity, mechanical shock, blood oxygen levels and glucose levels.’
In addition to asset management, a system like this could allow mHealth adaptations remote patient monitoring capabilities, reducing the demand for hospital beds. Other complex conditions, such as severe diabetes and allergies, could be monitored with the labels, providing advanced warnings based on blood analysis to patients and caregivers. Pets and children are other consumer markets that could utilize such a system.
RFID tags are incredibly important if the dream of quantifying every ‘thing’ in the world is to come true. That said, there are legitimate concerns regarding the necessity of tagging every physical object and knowing its precise location, but in the business and industrial sectors, asset tracking and management is an extremely valuable proposition.
The typical example implementation of such a system would be using tags to track a steak from its farm of origin, through the abattoir, through the processing plant, into the distribution chain where it can be monitored for dangerous temperature spikes, inside the supermarket, through a smart checkout, into the consumer’s smart fridge, then into the bin that keeps tabs on what you throw away so that the fridge can order more steak.
After the horse-meat scandal that rocked Europe, the benefits of having an automated chain of information about the product can be seen. It is just cost that acts as a deterrent to adoption, but now as these systems get cheaper the rate of uptake will soar.
RFID tags have a huge advantage over barcodes because they can be automatically read when a tag comes in range of a reader. Using a barcode, you would have to scan each barcode, usually using a person with a handheld unit to do so. RFID tagging allows a much more automated process.
Electromagnetically generated currents were used to power some RFID tags, which would be powered by the RFID reader’s magnetic field which would induct a current in the wires of the tag. The industry moved towards cheaper capacitively coupled tags, which worked in the same way as the inductively coupled tags but used conductive carbon ink instead of wires. A tiny microchip in the tag stores the necessary data, powered by batteries or induced current, which can be read-only, read-write, or write-once-read-many.
Now the industry uses a range of active, semi-active and passive tags. The more expensive active tags are usually reused but the cheaper passive tags were designed to be disposable (costing between seven and twenty US cents per tag).
Active RFID tags use batteries are able to communicate at ranges of up to 100 feet, or further if larger or more batteries are included. RFID tags typically use the 120-150kHz band, 13.56MHz, 433MHz, 865-868MHz, 902-928MHz, 2450-5800MHz, or 3.1-10GHz band to allow the RFID reader to discern location and status. Cellular TDMA can also be used for communication. These tags are termed active tags, as they use and require on-board power supplies to operate.
Passive tags have a much shorter range because they rely on the reader unit to power them, but can still operate at ranges of up to twenty feet. RFID installations can use a combination of active and passive readers.
Hitachi holds the record for the smallest tag built so far, at just 0.05mm2, the chip can store 38 digit numbers on its 128 bit read only memory. However, the read range is measure in millimeters rather than feet due to the tiny antenna. This means that things as large as trains and as small as ants can be successfully tracked in the physical world.