Plant Keeper: Towards Wireless Sensing to Ion Transmission of Plants

Plant sensing plays an important role in today's smart agriculture and intelligent forestry. However, existing plant sensing work based on wireless IoT mostly focuses on the environment that plants live like soil moisture and temperature of a greenhouse or a farm. The information about the surrounding environment does not reflect the physical condition of the plant itself. Taking ambient RF signal and commodity RFID tag as the fundamental sensing platform, we explore the Plant-Keeper, a real-time monitor system, which traces the physical state and biological activities of plants by perceiving Ion transmission in plants, like water content and the reaction of plants to an external stimulus such as Cut, Salt, Chilling, and Drought Stresses. We make the following technical contributions to achieve this goal. First, a theoretical model to verify that sensing the Ion transmission like Ca2+ channel and K+ channel by the low-power wireless backscatter technique are feasible; Second, a hardware-based non-invasive sensing system that can obtain the physical changes in plants by using the impedance-related RSS (Received Signal Strength); Third, a low-power low-cost implementation that based on a commercial RFID tag with the hardware structure we have proposed. Experimental results demonstrate that our system can monitor the ion channel changes of the whole plant systematically, and improve the detection accuracy to the millisecond level. The detection speed is 103 times that of the traditional patch-clamp technique, and the latter is not available for whole system inspection of plants in vivo.