In the era of smart lighting, LED lamps with integrated sensors improve energy efficiency and user experience. There are many types of sensors, among which passive infrared (PIR), wave and photocell sensors are the most common on the market.
This article will explore their differences in concepts, advantages, disadvantages, and applications, and hopefully help you choose the most suitable sensors.
Basic Understanding of Sensor LED Lights
Sensor LED Light is a lighting system that can automatically switch on or adjust brightness based on environmental conditions.
This lighting device combines the energy-saving properties of light-emitting diodes (LEDs) with sensor technology. The electronic sensor inside can detect motion or light changes within a specific range to activate or shut off the light.
Components of Sensor LED Lights
The main components of LED sensor lights include LED array, sensor, control circuit, power supply and protective enclosure.
The LED array emits illumination light, the sensor detects motion or light changes in the environment, and the control circuit analyzes the signal from the sensor and activates or shuts down the LED. The integration of these components ensures that the lamp can respond efficiently.
The power supply and enclosure are equally important. The former provides stable power to the lamp. It can be powered by wires, batteries or solar panels to meet the needs of different application scenarios. The latter protects the internal components from environmental factors and also improves the lamp's beauty.
Many modern sensor lights are also equipped with expansion components such as smart communication modules, dimming and color adjustment modules. This allows users to customize lighting according to their preferences, further improving convenience.
What are PIR, Wave and Photocell Sensor LED Lights？
Passive infrared (PIR) sensor light detects infrared light emitted by warm creatures and activates or turns off the light accordingly. It is passive because it doesn’t emit any signal - it only senses the heat emitted by people or animals.
Wave sensor light (also called doppler sensor or radar sensor light) actively transmits wave signals to a specified area, and a receiver retrieves the reflected signal to determine motion. The wave signals it emits are also divided into ultrasonic, microwave or tomographic waves based on different wave sensors.
The sensitivity of both motion sensors is usually adjustable, allowing users to customize the activation threshold, detection range, and light activation duration. This feature helps reduce false alarms caused by pets or passing vehicles.
Photocell Sensor LED Light (or light sensor LED light) doesn’t sense motion, it turns the light on or off by measuring changes in ambient light levels. The sensor resistance inside it changes with light changes. In bright daylight, the resistance drops and the light remains off; in darkness, the resistance rises and the light turns on.
Pros and Cons of Three Sensor Lights
PIR Sensor Light
Because PIR sensor light operates passively, it consumes little power and saves money. Its price is also not high.
Besides, it responds only to changes in biological heat, so false triggers are relatively rare. It tends to ignore non-thermal motion, such as moving branches.
Its disadvantages are also obvious. The detection range is limited (usually about 90° to 180°, not 360°). It can only detect within the line of sight, and cannot detect very small or stationary objects. When the ambient temperature is close to body temperature, the sensitivity decreases or causing false triggers.
Wave Sensor Light
Compared to PIR sensor light, wave sensor light has higher sensitivity and a wider detection area (usually 360°). It can also detect through thin walls, glass or other obstacles.
It is also not affected by ambient temperature, so it works reliably in hot or cold environments.
However, it is more expensive and consumes more power (because the transmitter is always on). It can also be overly sensitive and sometimes detect motion in adjacent rooms, causing false triggers. It is susceptible to interference if there are moving objects (fans, curtains) in the detection range.
Photocell Sensor Light
Photocell light only runs at night, saving energy. It also has no motion or heat triggers, so there are no false alarms.
However, since it can't detect motion or heat, the lights will stay on all night regardless of whether someone passes by. Ambient light (such as car lights) changes can interfere with its operation.
Typical Applications in LED Lighting
The three types of sensor lights have different applications based on different principles, advantages and disadvantages.
PIR sensor light is suitable for security and indoor lighting. Common outdoor uses include floodlights at entrances, motion-sensing porch or garden lights. PIR lights will emit light when someone walks by to deter intruders. Indoor areas include corridors, bathroom lights, etc.
Wave sensor light is suitable for large spaces that require extensive motion detection. Typical applications include warehouse lighting, office corridors, parking lots, and automatic doors. It is also suitable for outdoor lamps that need to detect motion passing through non-metallic obstacles.
Photocell Light automatically turns on the light at dusk and turns off the light at dawn. Commonly used in street lights, parking lot lights, landscape lights, and any lighting that only runs at night.
The following is a comparison table of the advantages, disadvantages and applications of the three:
Recommended Upgrade Option: Multiple Technology LED Sensor Lights
If you want the advantages of the above sensor lights, but also want to avoid their disadvantages, then multiple technology LED sensor lights are a good choice. It combines two or three functions of PIR, microwave and light sensing into one.
PIR + Photocell Sensor Light
This combination ensures the light is activated only when biological motion is detected and the ambient light is low. This maximizes energy savings and enhances convenience. The following are specific application examples:
Wave + Photocell Sensor Light
This setup takes advantage of the wide detection range and temperature insensitivity of microwave sensor, and the light sensing capabilities of light sensor. This is especially useful in large outdoor areas or environments with fluctuating temperatures, and reduces energy waste during the daytime.
PIR + Wave Sensor Light
This type of sensor light requires both the PIR and microwave to detect motion before triggering the light. This significantly reduces false alarms caused by environmental factors or small animals, improving accuracy. For example, it may ignore transient heat or radio noise unless both sensors confirm the presence of a real moving object.
Triple Technology Sensor Light
This combination means that the luminaire will only activate when it is dark and both motion sensors are triggered. The photoelectric sensor ensures that the luminaire remains switched off in daylight, and the PIR/microwave combination provides precise lighting.
Daylight Harvesting Technology of Photocell Sensor Light
To improve convenience and save energy, some photocell sensors in multi-sensor combinations will add daylight harvesting technology. This technology automatically adjusts its luminous brightness based on the environment brightness level to meet the constant illumination requirements (as shown below):
Today, the LED sensor light market is developing rapidly. The integration of emerging technologies such as artificial intelligence and the Internet with LED sensor systems is gaining increasing attention.
If you want to explore more smart single-sensor and multi-sensor LED solutions, please contact our team.
