Researchers at the University of California-Berkeley have used 3-D printing to build a smart packaging prototype that can detect when milk starts to go bad. The re-usable cap contains a wireless reader that senses electrical changes caused by bacteria growth.
3D-printed objects are traditionally made of polymers, which do not conduct electricity well. To work around this, the researchers injected liquid metal paste into a hollow, 3D-printed frame to create a full wireless system.
This type of smart packaging device could eventually see wide use. Eventually consumers could print them with 3-D printers intended for home use, according to Liwei Lin, a professor in UC Berkeley’s mechanical engineering department.
“One day you might be able to use your cell phone to detect the freshness of the product you are buying, instead of trusting the expiration label on the product. Similar to printing out papers by using regular printer at home now, we should be able to print out this smart cap sensor and other electronics by 3-D printers at home in the future.”