Where Is the Sensor on a Street Light?

In most cases, the sensor on a street light is the small, round “photocell” mounted on top of the fixture (the luminaire), often oriented to face away from direct sun; on some designs it’s a small window or dome on the side, and in smart lighting systems it may be a communication node on the top or a remote sensor in a nearby cabinet. This sensor tells the light when it’s dark enough to turn on and bright enough to turn off, and modern versions can also enable dimming and remote monitoring.

What the Sensor Does and Why It’s There

Street lights rely on photosensors to switch automatically at dusk and dawn, minimizing energy use and maintenance. The classic device is a photoelectric control (PEC) that senses ambient light. Newer smart nodes combine light sensing with wireless communications for remote control, dimming schedules, and fault alerts. In some specialty installations (pathways, underpasses, or parking areas), motion or presence sensors complement or replace a simple photocell to adapt lighting to activity levels.

Photocell/Daylight Sensor

This is the most common component. It reads ambient light and triggers on/off states. Traditional units are “hockey-puck” modules that twist-lock into a receptacle on top of the luminaire.

Smart Control Nodes

Many cities are upgrading to networked street lights. These top-mounted modules may include the photocell function plus radios for mesh or cellular communication, enabling dimming and diagnostics.

Motion or Presence Sensors

Less common on arterial street lighting but increasingly used on pathways and campuses, these sensors are typically mounted lower on the pole and aimed at the travel path to detect people or vehicles.

Where to Look on Different Street Light Styles

The exact location of the sensor depends on the luminaire design and control strategy. The following common setups show where you’re most likely to find it.

• Cobra-head/roadway fixtures: A round, twist-lock photocell or smart node sits on the very top of the luminaire. In North America, the sensor “eye” is often oriented north to avoid direct sun glare; elsewhere it may be oriented to reduce false triggers.
• LED shoebox/area lights: Similar top-mounted puck or a low-profile sensor window integrated into the housing near the top edge.
• Post-top and decorative lanterns: A small clear window or dome near the canopy or side of the lantern; sometimes a low-profile module on the top cap. On heritage retrofits, the sensor is often discretely integrated.
• High-mast lighting: May have a top-mounted sensor on one head or a remote photocell controlling the entire mast from a nearby cabinet.
• Tunnels and underpasses: Often no visible photocell on the fixture; lighting is controlled by luminance sensors at portals and a control cabinet that adjusts levels by time of day and traffic.
• Solar street lights: A photosensor is usually integrated into the solar controller or panel assembly; you may not see a separate puck on the luminaire.

While the “puck on top” remains the most recognizable indicator, integrated windows and remote controls are common, especially on decorative or complex systems.

How to Identify the Sensor in the Field

If you’re looking up at a pole and want to spot the sensor, these visual cues can help you distinguish the photocell or smart node from other hardware.

• Round “hockey-puck” module: About the size of a small jar lid, usually blue, gray, or black plastic, sitting on a small receptacle atop the luminaire.
• Small window or dome: A thumbnail-sized clear lens on the top or side of the fixture—common on integrated LED luminaires and decorative lanterns.
• Connector styles:
  – NEMA/ANSI C136 3-pin, 5-pin, or 7-pin twist-lock receptacles (typical in North America) for photocells or smart nodes.
  – Zhaga Book 18 low-profile connectors (common in Europe and newer global designs) on the top or side, sometimes with a compact node.
• Smart node telltales: Slightly taller module with a logo label, barcode/QR code, or a small antenna/vent; may have a discreet status LED.
• Remote cabinet controls: If no sensor is on the head, look for a nearby street-light control cabinet at the base of a pole row—the entire circuit can be photo- or time-controlled from there.
• Motion sensors: Small, angled units lower on the pole or under the luminaire, aimed at the roadway or walkway.

These identifiers help differentiate a standard photocell from advanced nodes and reveal when control is centralized rather than per fixture.

Regional Standards and Orientation

Standards influence appearance and placement. Understanding these norms can clarify why sensors look different from one city to another.

• North America: NEMA/ANSI C136 twist-lock photocells and smart nodes are common on the top of cobra-head and area lights.
• Europe and many newer deployments worldwide: Zhaga Book 18 connectors support compact, low-profile nodes on the top or side of LED luminaires.
• Orientation: Utilities often face the sensor window away from direct sunrise/sunset glare (commonly north in the Northern Hemisphere), but practice varies by utility and site geometry.
• Centralized control: Some municipalities forgo per-head photocells, relying on feeder pillars with photocells and time clocks that control entire circuits.

Local utility practices and procurement standards ultimately determine whether you see a prominent puck, a subtle lens, or nothing at all on individual fixtures.

Can’t See a Sensor? Possible Explanations

If a street light lacks an obvious top-mounted puck, the control method may be integrated or centralized. Many modern LED fixtures hide the photosensor behind a small lens, while smart-city systems may time and dim lights through a networked controller. In corridor or tunnel lighting, luminance sensors and cabinets often manage levels dynamically without visible per-head sensors.

Safety and Reporting Tips

If you’re investigating a malfunctioning street light, the following steps can help you report it effectively without taking risks.

• Do not touch or approach electrical equipment; never climb poles or open cabinets.
• Note the pole number or asset tag (usually a metal or plastic label at eye level).
• Record the exact location (street name, nearest address/intersection) and the problem (always on, always off, cycling, flickering).
• Submit a report via your city’s 311, utility website, or streetlight portal; attach a photo if safe to do so.

Providing precise details helps crews identify whether a failed photocell, smart node, lamp/driver, or circuit control is at fault.

Summary

The sensor on a street light is most often the round photocell or smart control node mounted on top of the luminaire; on some fixtures it’s a small lens on the top or side, and in networked systems control may be handled by a node on top or a remote cabinet. If you don’t see a puck, look for an integrated window, a compact Zhaga node, or evidence of centralized controls—then report issues using the pole ID and exact location rather than attempting any hands-on inspection.

How do I reset my outside light sensor?

You should consider resetting your fixtures if they’re showing signs of failure. Like they aren’t coming on when triggered. They never turn off even when set to do. So.

Which sensor is used in street lights?

Photocell Sensors: The Most Common Type of Street Light Sensors. The most commonly used type of street light sensor is the photocell sensor, which detects ambient light levels.

Where are street light sensors?

Some sensors are below the pavement, those sensors are activated by cars active electrical parts. Some sensors are located above or below the signal light, those sensors are for emergency vehicles they pick up on the emergency lights.

How to disable street light sensor?

Find the light sensitive sensor on the streetlight and aim it on that. It will take 20 seconds or so then it should disable for a few minutes. If you keep the laser trained onto the sensor, it will stay off all night.