Motion Sensor Symbol

The Motion Sensor schematic symbol. Standard-specific details are listed below where available.

Definition: The Motion Sensor symbol represents a detection device — most commonly a passive infrared (PIR) sensor or microwave detector — that outputs a signal when movement is detected within its sensing zone, used in lighting control, alarm, and occupancy systems per IEC 60617 and IEC 62642 security installation standards.

Also known as: PIR sensor, occupancy sensor, movement detector, presence sensor, passive infrared sensor, motion detector.

What the Motion Sensor symbol means

The Motion Sensor symbol in a wiring or circuit diagram denotes a device that monitors a zone for physical movement and switches its output signal from inactive to active when motion is detected. In most residential and commercial installations, the symbol appears in lighting control loops, alarm zones, and building automation circuits.

The symbol communicates the presence of a sensing element with two functional terminals: In (power/supply) and Out (switched or signal output). The sensor is passive until triggered — meaning it draws power continuously but only activates its output when motion exceeds the detection threshold, making it a key component in energy-saving occupancy-based lighting circuits.

How to identify the Motion Sensor symbol

The Motion Sensor symbol is typically drawn as a small rectangular or trapezoidal block with a radiating-arc or fan-shaped detection-zone indicator (representing the field of view) attached to one side. The label 'PIR', 'MOTION', or the IEC occupancy-sensor icon (a stylised person with radiating arcs) may appear inside or adjacent. Two terminals are shown: In on the left (power/input) and Out on the right (output signal or switched load).

Function and usage boundary

A motion sensor continuously monitors its detection zone using infrared radiation changes (PIR type), microwave Doppler reflection, or ultrasonic echo. When the sensor detects movement, it activates its output — either closing a relay contact, raising a logic-level signal, or switching a load directly. The output remains active for a hold time (typically 5 s–15 min, adjustable), then resets. PIR sensors are passive (detect emitted IR, not generate it), making them low-power; microwave and ultrasonic types are active (emit and receive).

Standards: IEC vs ANSI

IEC 60617	IEC 60617 includes occupancy/motion detection devices within the general sensor/detector symbol family. IEC 62642-1 governs alarm system detectors including PIR motion sensors; the symbol uses a rectangle with a fan arc for the detection field.
ANSI/IEEE 315	ANSI/NFPA 72 (National Fire Alarm and Signaling Code) and ANSI/SIA standards define motion detector symbols for alarm drawings; a rectangular block with a dashed detection-arc is commonly used in US security and life-safety drawings.
Key difference	IEC 60617 / IEC 62642 uses a filled detection-arc fan on the symbol; ANSI/NFPA 72 uses a dashed arc or abbreviation 'MD' (motion detector). Functionally identical; regional practice determines which symbol appears in a given drawing.

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Logical terminals

Logical ID	Editor terminal name
in	In
out	Out

Where the Motion Sensor symbol is used

Residential lighting control: automatically switches lights on when a person enters a room and off after a set hold time
Security alarm systems: triggers an alarm zone when motion is detected in a protected area
Building management systems (BMS): feeds occupancy data to HVAC and lighting controllers for energy optimisation
Outdoor security lighting: activates floodlights upon detecting movement in a driveway or garden
Access control systems: signals entry/exit events at doors or gates
Industrial safety: detects unauthorised entry into restricted machinery zones

Key facts

The Motion Sensor symbol represents a device that outputs a signal when movement is detected, used in lighting, security, and occupancy applications.
The two standard terminals are In (power/supply input) and Out (motion-detected output signal or switched output).
PIR (passive infrared) is the most common motion sensor type: it detects changes in infrared radiation emitted by warm bodies without generating any radiation itself.
PIR sensors typically operate at 5 V, 9 V, or 12 V DC; mains-powered types integrate a relay for direct load switching at 120/240 V AC.
Detection range for a standard PIR module is 5–12 m with a sensing angle of 90°–120°; ceiling-mount 360° PIR units cover up to 8 m radius.
Hold time (output active duration after last detected motion) is adjustable on most units, typically from 5 seconds to 15 minutes via onboard potentiometer.
IEC 62642-1 classifies passive infrared detectors as Grade 2–3 for intruder alarm applications; the motion sensor symbol appears on alarm installation diagrams accordingly.

Frequently asked questions

What does the motion sensor symbol mean in a wiring diagram?

The motion sensor symbol indicates a device that detects movement and activates its output (switching a load or raising a signal). It is shown as a rectangle with a detection-arc fan, with an In pin for power and an Out pin for the switched output.

What does the motion sensor symbol look like?

The motion sensor symbol is typically a small rectangle or trapezoid with a radiating fan or arc on one side representing the detection field. It is labelled 'PIR', 'MOTION', or 'MS'. Two terminals are shown: In (left, power) and Out (right, output signal).

What is the difference between a PIR sensor and a motion sensor in a schematic?

In schematic usage, 'motion sensor' and 'PIR sensor' refer to the same symbol. PIR specifies the sensing technology (passive infrared), while 'motion sensor' is the generic term. Both use the same rectangular block-with-detection-arc symbol in wiring diagrams.

How many pins does a motion sensor have?

The standard motion sensor schematic symbol shows two functional pins: In (power/supply) and Out (output). Physical PIR modules typically have three wires — VCC (power), GND (ground), and OUT (signal) — but the In pin on the symbol represents the entire power supply connection.

What voltage does a motion sensor operate at?

PIR motion sensor modules typically operate at 5 V, 9 V, or 12 V DC. Mains-wired motion sensor luminaire controllers operate at 120 V or 240 V AC. The operating voltage is printed on the device or in the datasheet, not encoded in the symbol itself.

What standard defines the motion sensor symbol?

Motion sensor symbols for alarm systems are defined in IEC 62642-1. General occupancy detector symbols follow IEC 60617 sensor conventions. In US life-safety drawings, ANSI/NFPA 72 governs motion detector symbology.

What are common applications of the motion sensor in circuit diagrams?

Motion sensors appear in lighting control circuits (automatic on/off by occupancy), security alarm systems (zone detectors), HVAC occupancy sensing, access control, and outdoor security lighting. The Out pin typically drives a relay, MOSFET, or logic input.

Related symbols

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