A light sensor is a photoelectric device that converts light energy (photons) detected to electrical energy (electrons). Seems simple? There is more to a light sensor then just its definition. It comes in different types, used in various applications and more! Hence, in today’s light sensor guide, we’ll be exploring all you need to know about light sensors:
What are the types of light sensor
There are different types of light sensors available; mainly Photoresistor, Photodiodes, and Phototransistors. Sounds technical? I’ll break it down with the explanations below!
1. Photoresistors (LDR)
The most common light sensor type that’s used in a light sensor circuit are photoresistors, also known as a light-dependent resistor (LDR). Photoresistors are used to simply detect whether a light is on or off and compare relative light levels throughout a day.
What are photoresistors made of?
- A high resistance Semiconductor material called cadmium sulfide cells, highly sensitive to visible and near-infrared light
How photoresistors work?
As its name suggests, photoresistors work similarly to your regular resistors, but instead resistance change is dependent on the amount of light it’s exposed to.
- High intensity of light causes a lower resistance between the cadmium sulfide cell
- The low intensity of light results in a higher resistance between the cadmium sulfide cells
This working principle can be seen in applications such as street lamps, wherein the day, the higher light intensity results in lower resistance and no light produced.
Photodiodes are another type of light sensor. But instead of using the change in resistance like LDR, it’s more complex to light, easily changing light into a flow of electric currents.
Also known as a photodetector, photo sensor
What are photodiodes made of?
- Photodiodes are mainly made from silicon and germanium materials and comprise of optical filters, built-in lenses and surface areas
How photodiodes work?
Photodiodes work on the working principle called the inner photoelectric effect. To simply put it, when a beam of light hits, electrons are loosened, causing electron-holes which results in electrical current to flow through.
- The brighter the light present, the stronger the electrical current will be
Photodiode light sensor applications
Since current generated by photodiodes are directly proportional to the intensity of light, it makes it favorable for light sensing that requires fast light response changes.
Since photodiodes are responsive to infrared light, it’s applicable for more usages as well.
Here are some of the applications of photodiode:
- Consumer electronics ranging from compact disc players to smoke detectors and even remote control devices
- Medical applications such as equipment/instruments used for measuring and analysis purposes
- Solar energy systems such as solar panels
The last light sensor type we’ll be exploring today is the phototransistor. The phototransistor light sensor can be described as a photodiode + amplifier. With the added amplification, light sensitivity is far better on the phototransistors.
- However, it doesn’t fair better in low light level detection as compared to photodiodes.
Since both light sensor types share a similar working principle, do refer to the previous explanation!
here is my list of The 10 Best Outdoor Motion Sensor Lights.
1. URPOWER Outdoor Motion Sensor Lights
The URPOWER Outdoor Motion Sensor Lights features solar panels that recharge the batteries during the day that then provides up to 12 hours of light.
- Automatically turns the light off during the day to save energy.
- Features a standard operation that turns on at night when motion is detected.
- Turns off 30 seconds after motion stops.
- Takes 6-8 hours of sunlight to fully charge.
- Equipped with a three-meter and 120-degree detection range.
- Offers a weatherproof and heatproof design for outdoor use.
2. Aootek LED Outdoor Motion Sensor Light
Aootek 182 Led Solar outdoor motion sensor lights upgraded Solar Panel to 15.3 in2 and 3 modes(Security/ Permanent On all night/ Smart brightness control )with IP65 Waterproof with Wide Angle(2pack)Aootek
The Aootek LED Outdoor Motion Sensor Light features on-board solar panels that charge and power the lights at night.
- Features three modes of operation:
- Standard mode – light turns on if movement is detected.
- Always on mode – provides constant illumination at night.
- Smart mode – provides constant illumination and becomes brighter if movement is detected.
- Detects movement within an angle of 120 degrees up to 26 feet.
- Equipped with a rechargeable lithium-ion battery.
- Features a waterproof IP65 rating.
3. LEPOWER LED Outdoor Motion Sensor Light
The LEPOWER LED Outdoor Motion Sensor Light features a durable full aluminum design.
- Powered by Samsung LEDs to provide soft light, anti-glare illumination.
- Features a detection range can be up to 72ft at an angle of 180 degrees.
- Offers the ability to customize the sensing range and lighting time.
- Includes a IP65 waterproof rating.
4. Brightech LightPRO Outdoor Motion Sensor Light
Brightech – LightPRO LED Yard Light – Brightest & Most Cost-Effective Security Light on The Market – 56 Watts – Dusk to Dawn Photocell Outdoor LED Wall Mount Barn Light & Area Lighting FloodlightBrightech
The Brightech LightPRO Outdoor Motion Sensor Light features a color temperature of 5,000K with 4,000 lumens.
- Offers 120 degrees of motion detector coverage.
- Features an integrated LED bulb that lasts over 20 years or around 50,000 hours.
- Operating temperature range from -40°F to 113°F.
- Mounts to a wall or clamps to a pole.
5. Heath HZ-4150-BK Outdoor Motion Sensor Light
The Heath HZ-4150-BK features a coach-style lantern design.
- Detects motion in a 150-degree zone with a range of up to 30 feet.
- Offers the ability to customize the light to remain on for up to ten minutes.
- Features an adjustable motion sensor to increase or reduce the sensitivity.
- Equipped with a weather-resistant finish for outdoor use.
6. Hyperikon Outdoor Motion Sensor Light
The Hyperikon light features a spotlight-style design that allows the targeting of light in two specific directions.
- Equipped with adjustable light timing and motion sensor range for customization.
- Includes a rotating cap.
- Features a 150-degree range of motion detection.
- Offers a light angle of 100 degrees for overall coverage.
- Includes an IP65 rating for outdoor use.
7. Oberlin Outdoor Motion Sensor Light
The Oberlin light features a mission-style design for a unique look.
- Equipped with a dusk-to-dawn photocell sensor for continuous operation.
- Features a sensor that allows for motion-activated illumination.
- Offers adjustable sensitivity for motion detection to customize for the particular application.
- Includes 220 degrees of detection.
- Features a 10 to 40-foot range.
8. Heath HZ-5411-WH Outdoor Motion Sensor Light
The Heath HZ-5411-WH features a pulse-count motion detection system to reduce the occurrence of false activations.
- Includes three modes that allow for either one, five or ten minutes of illumination after motion is detected.
- Equipped with 150-degrees of motion detection.
- Offers detection for up to 70-feet away.
- Includes a manual override setting for continuous illumination.
9. Sunforce Outdoor Motion Sensor Light
The Sunforce light includes a solar panel to recharge the onboard AA batteries.
- Features two adjustable settings:
- Duration the light remains on after detecting motion can be set to 30, 60, or 120 seconds.
- Distance of the motion detection can be set to either high, medium, or low.
- Offers a detection range of 180 degrees.
- Features a Detection distance of up to 30 feet.
- Equipped with a weather-proof design for outdoor use.
10. Mr. Beams Outdoor Motion Sensor Light
The Mr. Beams light features LED bulbs for long-lasting use.
- Features a sensor that can detect motion up to 30 feet away.
- Offers 180-degrees of motion detection.
- Automatically shuts off after 30 seconds once no motion is detected to save battery life.
- Features an all-weather design for outdoor applications.
- Illuminates up to 350 square feet.
I hope this list of the best outdoor motion sensor lights was helpful.
If you think I left out one that is important or have a suggestion for a future article, let me know in the comments below.
Brandon Hubbard, AIA, NCARB, LEED AP BD+C