This demo presents an innovative wireless sensor platform for oxygen monitoring, featuring LoRa connectivity and a unique battery-free operation to ensure maintenance-free usage. The platform integrates an advanced oxygen sensor and leverages LoRa technology to transmit data efficiently over long distances. Powered by a photovoltaic cell, the system is independent of conventional batteries, eliminating the need for periodic replacements. The photovoltaic cell supplies energy for the sensor’s operation and charges a 1F supercapacitor, ensuring continuous operation without light. The 1F supercapacitor allows the system to acquire data from the oxygen sensor and transmit it via LoRa connectivity with a configured spreading factor of 7 every 10 minutes for up to 10 hours without light.

Food production is one of the main contributors to climate change and its impact is set to increase due to population growth. Smart agriculture aims at providing solutions to reduce food production and environmental impact while, at the same time, increasing crop production. This paper proposes a system based on STDES-BTAG01 by STMicroelectronics to monitor in-vivo stem electrical impedance, which is a parameter that has recently demonstrated its efficacy in assessing information about plants' water stress status. The developed system is completely battery-free and equipped with a wireless communication module to transmit the acquired data. It is powered by a small amorphous solar cell and transmits data to a base station exploiting the Bluetooth Low Energy (BLE) protocol. The system monitors the needed time to discharge a capacitor through the plant stem. After this, this span of time is used to compute the stem electrical impedance. Tests showed reading errors lower than 15% when dealing with impedance modules up to 180 kΩ. System characteristics (energy self-sufficiency, compactness, and low-power consumption) make the system implementable in the fields.

This paper introduces an innovative Energy-Autonomous Wireless Sensing Node (EAWSN) that addresses power constraints by harnessing ambient light for energy. It combines this energy harvesting capability with the Time Domain to Digital Conversion (TDDC) technique for efficient and accurate measurements of resistive sensors. Bluetooth Low Energy (BLE) communication ensures data can be transmitted wirelessly to a base station, providing a promising solution for various applications, particularly in environments with limited access to wired power sources, enabling long-term, maintenance-free operation by eliminating batteries. Experimental results showed a linear relationship between the test resistance Rmand the measured number of clock pulses Nmwithin the sensor’s operating range.

In order to increase energy efficiency in electrical appliances, autonomy in WSN (Wireless Sensor Network) nodes, IoT (Internet of Things) devices and self-powered sensors, it is necessary to reduce energy consumption as much as possible. One of the main issues to solve is reduction of standby power consumption, which is not negligible due to the enormous number of appliances involved. While in standby, power management circuits are permanently on, consuming unnecessary energy. This leads designers to consider power efficiency. In this article, a different approach is introduced based on Radio Frequency to electrical energy transduction with the intention to resolve this issue. The proposed solution goes beyond the well-known concept of standby as it instead applies to electric appliances that are off. An RF powered receiver silicon IC (integrated circuit) for remotely controlled systems is presented. This includes an RF-to-DC energy converter specifically designed with a sensitivity of -18.8dBm, which allows an operating distance of up 8 meters at 900 MHz with a transmitting power of 1Watt in free space. Experimental results using a complete working prototype will be shown.