Batteryless Sensor Using Solar Harvesting for Occupancy Detection
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Solution Overview
Problem
Existing occupancy tracking devices in commercial buildings require wired connections or batteries, leading to high energy consumption, maintenance costs, and structural modifications, which hinder widespread deployment and energy efficiency.
Innovation Solution
A batteryless, self-powered sensor system using solar panels to harvest energy and detect motion, with a microprocessor and transceiver to transmit data wirelessly, eliminating the need for batteries and wired connections, and allowing for easy installation and low maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wired connections are used to provide power and connectivity to sensors, then reliable power supply and data transmission are achieved, but installation cost and structural modification requirements increase
Solution Approach 1:
The patent replaces the mechanical wired connection system with a wireless communication system. Sensors transmit data and receive commands wirelessly through radio frequency communication, eliminating the need for physical cable connections while maintaining reliable data transmission and control capabilities.
Solution Approach 2:
The patent implements energy harvesting technology that allows sensors to generate their own power from ambient light sources. The solar panel integrated into each sensor continuously charges an onboard capacitor, enabling the sensor to be self-powered without requiring external wired power connections, thus achieving both reliability and ease of installation.
2Ease of operation
If batteries are used to power sensors, then wireless operation is achieved, but maintenance cost and operational duration are worsened due to frequent battery replacement
Solution Approach 1:
The patent employs energy harvesting through integrated solar panels that continuously convert ambient light into electrical energy. This harvested energy charges an onboard capacitor, providing continuous power to the sensor without requiring external battery replacement. The system sustains itself by capturing energy from the environment, dramatically extending operational duration indefinitely.
Solution Approach 2:
The patent changes the power source parameter from finite chemical energy storage (batteries) to continuous renewable energy harvesting (solar power). This parameter change transforms the operational duration from limited by battery capacity to potentially unlimited by ambient light availability, eliminating the maintenance burden of battery replacement.
3Measurement precision
If traditional sensors are deployed to track occupancy, then motion detection capability is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent replaces traditional active sensing mechanisms that consume continuous power with a passive energy harvesting approach. The solar panel passively captures ambient light energy without requiring active power consumption, while the microcontroller processes sensor data efficiently in low-power mode, achieving accurate motion detection with minimal energy usage.
Solution Approach 2:
The patent implements periodic sampling of sensor data rather than continuous monitoring. The microcontroller activates sensors and processing only when needed, entering low-power states between measurements. This periodic operation maintains detection accuracy while dramatically reducing average energy consumption to match the harvested power capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively detects motion with high accuracy, reduces energy consumption to less than 18 μA, and integrates seamlessly with smart building systems to optimize energy use by turning off unnecessary lights and HVAC in unoccupied spaces.
Implementation Method 1
A batteryless sensor is described that harvests power from solar panels
Implementation Method 2
This sensor uses light reflections to detect objects moving through spaces
Data Source
AI summary
This system is directed to a batteryless, self-powered sensor comprising: a microprocessor; a first and second solar panel in electronic communications with the microprocessor; a transceiver in communication with the microprocessor; and a set of computer readable instructions included in the microprocessor adapted for creating motion data including a direction and a speed of movement of object within a first sensing area and a second sensing area, transmitted the motion data to a remote location if sufficient power is provided by the first solar panel to actuate the transceiver and a number of data points in the motion data exceeds a pre-determined number of minimal data points, associating a reduction in power delivered from the first solar panel to the microprocessor with movement and associating an increase in power delivered from the first solar panel to the microprocessor with movement.