New Tech :: Printed Stickers Designed to Monitor Food Temperatures

A plastic temperature-recording sticker that could provide detailed histories of crates of food or bottles of vaccine would be the first to use all-printed electronics components—including memory, logic, and even the battery. The cost per sticker could be only 30 cents or less.

Thin Film Electronics, based in Oslo, Norway, aims to marry the company's printed memory with printed transistors from PARC in Palo Alto, California; a printed temperature sensor from PST Sensors, a spin-off from the University of Cape Town in South Africa; and a printed battery from Imprint Energy, a spin-off from the University of California, Berkeley. The first prototype using all the components is expected later this year.

"There are lots of efforts in academia and research where they play with printing electronics," says Janos Veres, who manages the printed electronics team at PARC. What's new is "somebody trying to do it commercially and figuring out what are the first things you can make with 10 or 20 bits of memory and a simple battery," he says. "We need a library of different building blocks that are made by the same standard manufacturing process to get this ecosystem working."

The envisioned product will be designed to work either with a printed display or a contact readout, and include a battery that can last six to nine months, allowing the sticker to make a continuous record of temperature. Existing temperature sensor stickers that cost just pennies offer a crude measurement—using a chemical reaction to change color when they hit certain thresholds, alerting to possible spoilage. 

Printed power: Printed rechargeable battery cells, made by a startup spun out of the University of California, Berkeley, can be made in various shapes. They will be used to power the temperature monitoring system.