Low-Cost Wireless Humidity Sensors for Smart Packaging

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Researchers at Purdue University have developed a method to create humidity sensors to monitor moisture levels in packaged goods. One of the major causes of food spoilage is the presence of excess moisture in the package of both fresh (i.e., fruits and vegetables) and dried products. Nearly one-third of all food produced for human consumption is discarded due to improper packaging and spoilage. Smart packaging technologies with integrated sensors that can monitor the quality of the product and the package reduces food waste by maximizing the shelf life of products and notifying consumers of accurate information about the packaged product. Although remote sensing and wireless communication approaches have been widely used for automobiles and agriculture, their use in packing goods is rare; it's not economically feasible due to the cost of components and fabrication process. Purdue researchers have developed a scalable and cost-effective process of manufacturing low-cost humidity sensors for wireless monitoring of moisture through selective laser ablation of metalized paper. In this process, the aluminum layer on the paper serves as both a highly conductive material for creating the circuit traces of the sensor as well as a precursor for creating moisture-sensitive, nanostructured alumina directly on the parchment paper substrate. The rapid laser processing technology and inexpensive materials used in this process allow the sensors to be fabricated economically, thereby making them suitable for disposable packaging applications in which the cost of production is crucial for the viability of the technology.

Technology Validation: The Purdue researchers' sensor has a 10-fold higher sensitivity to humidity than a similar LC resonant sensor prepared by conventional photolithography processes.

- Low-cost
- Wireless
- One-step laser processing
- Battery free
- Electronic free
- Scalable
- Paper based sensors

- Remote and battery free humidity sensing in packaged products
Jan 31, 2023
Utility Patent
United States

Mar 31, 2022
United States
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