A team of PhD scientists had developed a method to measure an odor emitted by cat and dog food, which correlated to the product’s freshness. The odor caused a resistance change in a chemical sensor. They believed that putting one of these sensors in each food bag could eliminate the need for sell-by dates and significantly extend the product’s shelf life.
The scientists turned to Henway for a custom electronic solution. During our initial meetings, they presented data graphs showing the resistance changes over time and theoretical mathematical models, and we provided evidence that UHF RFID technology was their optimal path forward. We proposed using electronics that could harvest RF energy to power a microcontroller and the necessary auxiliary circuitry without batteries, saving size and cost.
The proposed circuit is highly advanced, capable of handling analog-to-digital conversions and managing standard digital interfaces like SPI and I2C, from the energy it harvested from the RF field, without batteries. Our engineers have this to say about RF energy harvesting:
“The key to maximizing the range from the UHF RFID interfaces is to optimize the power consumption of the electronics. By carefully managing the firmware, we can minimize core execution time by using interrupts instead of polling, leveraging peripheral features to reduce code execution, and maintaining efficient and clean code to avoid unnecessary power consumption. We also have to consider the trade-off between sample rate and range—higher sample rates would increase power consumption and reduce range. Balancing these factors was crucial during the system design stage.”
Once the customer approved our approach, we moved into the design phase and created a prototype. In the end, we achieved an impressive 4 meters of range using the EPC interface, with a sample rate of one measurement per second. We could also measure hundreds of bags nearly simultaneously simply by bringing them within range of the UHF transmitter. The customer was extremely satisfied with the results, which validated their concept and set the stage for further development.
This project highlights Henway Engineering’s ability to tackle highly specialized and complex challenges, turning innovative ideas into practical, tangible solutions. Whether you’re a research team or a commercial enterprise, Henway has the expertise to bring your most ambitious projects to life, from initial research through to final production. Contact us.