A uW Backscatter-Morse-Leaf Sensor for Low-Power Agricultural Wireless Sensor Networks

Spyridon Nektarios Daskalakis, George Goussetis, Stylianos D. Assimonis, Manos M. Tentzeris, Apostolos Georgiadis

Research output: Contribution to journalArticlepeer-review

104 Citations (Scopus)
103 Downloads (Pure)


Nowadays, the monitoring of plant water stress is of high importance in smart agriculture. Instead of the traditional ground soil-moisture measurement, leaf sensing is a new technology, which is used for the detection of plants needing water. In this work, a novel, low-cost and low-power system for leaf sensing using a new plant backscatter sensor node/tag is presented. The latter, can result in the prevention of water waste (water-use efficiency), when is connected to an irrigation system. Specifically, the sensor measures the temperature differential between the leaf and the air, which is directly related to the plant water stress. Next, the tag collects the information from the leaf sensor through an analog-to-digital converter (ADC), and then, communicates remotely with a low-cost software defined radio (SDR) reader using monostatic backscatter architecture. The tag consists of the sensor board, a microcontroller, an external timer and an RF front-end for communication. The timer produces a subcarrier frequency for simultaneous access of multiple tags. The proposed work could be scaled and be a part of a large backscatter wireless sensor network (WSN). The communication protocol exploits the low-complexity Morse code modulation on a 868 MHz carrier signal. The presented novel proof-of-consent prototype is batteryless and was powered by a flexible solar panel consuming power around 20 μW. The performance was validated in an indoors environment where wireless communication was successfully achieved up to 2 m distance.

Original languageEnglish
Pages (from-to)7889-7898
Number of pages10
JournalIEEE Sensors Journal
Issue number19
Early online date31 Jul 2018
Publication statusPublished - 1 Oct 2018


  • Agriculture
  • Backscatter
  • Backscatter sensor networks
  • environmental monitoring
  • Frequency modulation
  • Internet-of-Things (IoT)
  • leaf sensor
  • Morse code
  • precision agriculture
  • radio frequency identification (RFID) sensors
  • software-defined radio (SDR)
  • Temperature measurement
  • Temperature sensors
  • Wireless sensor networks

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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