Security cameras have become a fundamental part of residential, commercial and industrial safety systems. Many industry reports forecast that security cameras will come into second place, only after mobile handsets, in terms of image sensor volume by application, by 2030. With technology advancements, the trend is moving towards wireless, battery-powered cameras because of their ease of installation and flexibility. However, one major challenge that these cameras face is power consumption. These cameras are often placed in out-of-way locations, therefore frequently replacing or recharging batteries can be burdensome. This becomes even more challenging with multi-camera systems. Efficient power management is critical to extending battery life, ensuring that cameras remain operational over long periods.
The primary consumers of power in a camera include the main processor, infrared LEDs (used in dark conditions), and of course, the image sensor. Since the image sensor itself is the primary source of data for which the entire system is built upon, it means that the sensor needs to be in operation 24/7 one hundred percent of the time. With proper design, the sensor can build in functionality that not only reduces the native power of the device itself, but the entire camera system.
An exceptionally effective technique for optimizing power consumption in battery-operated security cameras is a feature recently introduced into onsemi sensors known as Wake-on-Motion. In this blog we will explore how Wake-on-Motion technology works, and its ability to substantially reduce power.
The Challenge of Power Consumption in Battery-Powered Cameras
Battery-powered security cameras offer several advantages, such as flexibility in placement, reduced installation costs and portability. However, these benefits come with the tradeoff of having to recharge or replace batteries in these remote cameras. Frequent battery replacement or recharging becomes a hassle, especially in locations where access is limited. Traditional battery-powered cameras can consume significant power as they operate continuously with zero downtime. As many sensors do not have the ability to detect motion, nor have scalable low power states, the main processor is relied upon to detect and classify such motion. In this circumstance, both the sensor and the processor are constantly draining power.
To address this challenge, onsemi has incorporated the Wake-on-Motion feature into their Hyperlux LP (Low-Power) and Hyperlux LH families of image sensors. Wake-on-Motion technology enables cameras to operate in an ultra-low power state, only activating fully when motion is detected. This approach significantly reduces the amount of power the camera consumes during idle periods, thus extending battery life.
How Wake-on-Motion Works
Wake-on-Motion functions by keeping the image sensor in a low-resolution, low-frame-rate, pre-detect mode when no motion is present. This mode consumes less than 1/100th of the power required during full operation, meaning the camera is essentially in a sleep state. When the sensor detects movement, it triggers the system to wake up through an interrupt, and transmits the image to processor to determine if that object requires it to switch to its full-resolution, high-frame-rate mode to capture and process the footage.
Here’s a breakdown of the key stages in Wake-on-Motion operation:
1. Pre-Detect State: The sensor is put into an optimized ultra-low power, low-resolution, low frame rate mode, consuming minimal power while detecting any signs of motion. If additional power reduction is desired, the sensor can even be put into standby, only going into its ultra-low power mode when a Passive Infrared (PIR) detects motion.
The Wake-on-Motion functionality is further enhanced by a 16x9 grid, in which the end-user and processor can dictate to the sensor which regions it determines on motion detection. This reduces faulty detection discussed later.
2. Motion Detection: When movement is detected within the field of view, the sensor alerts the image signal processor (ISP) or system-on-chip (SoC) through an interrupt. The ISP/SoC then verifies the motion’s relevance to the application (differentiating between a person approaching and a tree swaying in the wind, for example).
3. Full Activation: If the motion is relevant, the image sensor and the camera's processing system activate fully, capturing high-resolution footage and alerting the user or security system as needed, additionally storing footage in local non-volatile memory.
4. Return to Pre-Detect: Once the footage is captured, and motion is no longer detected, the system returns to the low-power, pre-detect mode until another motion event occurs.
Benefits of onsemi’s Wake-on-Motion for Battery-Powered Cameras
Wake-on-Motion offers multiple advantages for battery-powered security cameras, making it an ideal solution for those seeking long-term, efficient surveillance systems:
1. Extended battery life
Industry trends indicate that the goal for battery-powered cameras is to achieve 180-day charging cycles, with some manufacturers targeting up to a year of continuous operation. onsemi’s Wake-on-Motion is a step toward achieving this goal, minimizing the need for frequent battery maintenance.
By keeping the camera in a low-power state when no motion is present, Wake-on-Motion conserves battery energy, extending the camera's operational cycle. Furthermore, the main processor can enter standby mode, only waking when an interrupt is sent from the sensor indicating motion. This multiplies the power savings at a system level.
2. Optimized performance without compromising quality
Typically, full resolution and frame-rate operation is only necessary for a brief period, allowing the sensor to remain in the low-power, pre-detect state for the majority of the time. While the camera operates in ultra-low power mode during idle periods, it quickly switches to full functionality when motion is detected. This ensures that the system captures clear, high-resolution images whenever it is necessary, without compromising the quality of the image stream of the security camera. This capability is crucial for applications where reliable and timely monitoring is required, such as around entry points of homes, businesses, or restricted areas in industrial sites.
3. Reduced false alarms
One of the common issues with motion-detection systems is false alarms caused by irrelevant motion, such as swaying trees and small animals. onsemi’s Wake-on-Motion system incorporates advanced capabilities that allow the sensor to differentiate between significant events and background activity. By filtering out irrelevant movement, the technology reduces the number of false alarms, ensuring that the system only activates for genuinely important events.
Implications for Homeowners and Businesses
For homeowners, security cameras with onsemi’s Wake-on-Motion offer peace of mind and convenience. With extended battery life, users do not need to worry about frequent recharging, making it a set-it-and-forget-it solution for home security. Whether monitoring the front door, backyard or driveway, these cameras provide efficient surveillance without the need for constant maintenance.
Businesses and industrial facilities also benefit significantly. In commercial and industrial settings, security cameras are often deployed in difficult-to-access areas, such as high up on building exteriors and on ceilings. Reducing the frequency of battery replacements not only saves on labor costs, but also ensures that the cameras remain functional and reliable over longer periods. This is particularly important for businesses that rely on continuous monitoring for safety, theft prevention and compliance.
Designed to the Low-power Needs of the Security System
Optimizing power consumption in battery-powered security cameras is crucial for ensuring efficient, long-lasting performance. onsemi’s Wake-on-Motion technology offers a practical solution that balances low power consumption with high-quality surveillance. By extending battery life and enhancing reliability, Wake-on-Motion allows for more flexible and cost-effective deployment of wireless security cameras, making them a valuable addition to any modern security system.
Learn more:
Security and Surveillance Cameras Solution
Security & Surveillance SSG
Hyperlux LP
Hyperlux LH
PRISM Modules
