Nowadays, Embedded Designers are challenged to create self-sustaining energy harvesting systems with low-cost while offering environmental benefits. Energy Harvesting generally involves powering a wireless sensor node’s battery which is a thin-film battery. This battery acts as a low-leakage device and a large power container. From this container, energy is consumed in very short bursts over a long time. This is important as the main challenge to implement wireless sensor node is availability of very low power budget. The reason is that a wireless node can be placed anywhere where mains are not available and changing battery becomes costly.
Solar-powered wireless sensor node is most popular although many other forms of energy can be harvested. These nodes always remain powered as they continuously harvest energy and use wireless MCUs and sensors that remain in ultra-low-power or deep sleep modes. The MCUs are able to do monitoring of sensor data and battery parameters, and sending of data wirelessly for graphical analysis, for example, to a PC, while remaining in low-power mode. This allows making nodes with a range of many meters and several years life span. This way, they are ideal for building security systems, industrial automation, smart homes and agricultural systems.
To know more, let’s walk through some energy harvesting reference designs discussed below with complete documentation:-
- Solar powered Wireless Sensor Node using Wireless MCU: Here is an awesome reference Design for embedded designers describing how to create an extremely low power wireless sensor node application with the help of a wireless microcontroller. This wireless node is used to harvest energy and remain powered at all times making them ideal for industrial automation, smart homes, and more. The system always remains powered from a solar cell array by remaining in ultra-low-power mode. No batteries need to be replaced for the life of the system giving a life expectancy greater than 15 years or 7000 mA-H. The wireless node can be designed with a very thin profile with battery height of 0.17 mm. The harvested solar power is stored in a thin film battery. The wireless Si1xxx MCU measures temperature from the on-chip temperature sensor on MCU, remaining charge level on the thin battery and light level from the voltage across solar array. This data can be analyzed graphically on a PC GUI by sending it wirelessly to a USB adapter connected to a PC. More on this Reference Design
- Battery-Operated Wireless Sensor Monitoring Reference Design: This design implements a low-power wireless sensor node operated by a battery. The wireless node can be used in a wide range of low-power applications including alarm and security (smoke detectors, glass breakage detectors, carbon monoxide sensors, and light sensors), home automation (appliances, garage door openers) and active RFID. The design centers on an ultra-low-power MCU from Texas Instruments (MSP430) and a low-cost 2.4 GHz transceiver (CC2500) designed for very low-power wireless applications. The wireless node data is sent to an access point wirelessly using a network protocol called “SimpliciTI”. A USB debugging interface enables the MSP430 application to remotely send and receive data from a PC. A PC GUI is used to analyze the data received from various nodes to the access point. The design files, BOM, source code and user guides are included in the reference design. More on this Reference Design