UC Berkeley engineers, in collaboration with colleagues at Taiwan’s National Chiao Tung University, are expanding the already impressive portfolio of 3D printing technology to include electrical components, such as resistors, inductors, capacitors and integrated wireless electrical sensing systems. They have put the new technology to the test by printing a wireless “smart cap” for a milk carton that detected signs of spoilage using embedded sensors.
The researchers integrated the electronic components into a plastic milk carton cap to monitor signs of spoilage. The “smart cap” was fitted with a capacitor and an inductor to form a resonant circuit. A quick flip of the carton allowed a bit of milk to get trapped in the cap’s capacitor gap, and the entire carton was then left unopened at room temperature (about 71.6 degrees Fahrenheit) for 36 hours.
The circuit could detect the changes in electrical signals that accompany increased levels of bacteria.