RFTemp: Monitoring Microwave Oven Leakage to Estimate Food Temperature

Microwave ovens have been widely used in recent years to heat food quickly and efficiently. Users estimate the time to heat the food by prior knowledge or by trial and error process. However, this often results in the food being over-heated or under-heated, destroying the nutrients. In this paper, we present RFTemp, a system that can monitor microwave oven leakage to estimate the temperature of the food that is being heated and thus estimate the accurate time when the food has reached the targeted temperature. To design such a system, we propose an innovative microwave leakage sensing procedure and a novel water-equivalent food model to estimate food temperature. To evaluate the real-world performance of RFTemp we build a prototype using software defined radios and conducted experiments on various food items using household microwave ovens. We show that RFTemp can estimate the temperature of the food with a mean error of 5°C, 2x improvement over contactless infrared thermometer and sensors.