HC-SR501 is based on infrared technology, automatic control module, using Germany imported LHI778 probe design, high sensitivity, high reliability, ultra-low-voltage operating mode, widely used in various auto-sensing electrical equipment, especially for battery-powered automatic controlled products.


ESP8266 Arduino HC-SR501 PIR 인체 동작 감지센서 구입하기>>


  • Use BISS0001 signal processing IC, sanyo genius regulator
  • Voltage: 5V – 20V
  • Power Consumption: 65mA
  • TTL output: 3.3V, 0V
  • Delay time: adjustable (0.3 sec – 10 minutes)
  • Lock time: 0.2 sec
  • Trigger methods: L – disable repeat trigger, H enable repeat trigger
  • Sensing range: less than 120 degree, within 7 meters
  • Temperature: – 15 ~ +70
  • Dimension: 32*24 mm, distance between screw 28mm, M2, Lens dimension in diameter: 23mm


Automatically sensing light for Floor, bathroom, basement, porch, warehouse, Garage, etc, ventilator, alarm, etc.


  • Automatic detecting: the output will be high when objects enter the sensing range, and automatically turn to low when object leave
  • Photosensitive control (optional, not factory-set yet) can be set.
  • Temperature compensation (optional, factory reset): In the summer when the ambient temperature rises to 30 ° C to 32 ° C, the detection distance is slightly shorter, temperature compensation can be used for performance compensation.
  • Working mode (set by jumper)
    ** Non-repeatable trigger/ delay mode (set to LOW): the sensor will turn to low TTL after the delay, even the sensing object is still in range.
    ** Repeatable trigger (set to HIGH): the sensor will not turn to low if the object still staty in the sensing range in the delay time.
  • Wide operating voltage range: default voltage DC4.5V-20V.
  • Micro-amp power level consumption: static current <50 microamps, particularly suitable for battery-powered automatic control products.
  • Output high signal: easy to achieve docking with the various types of circuit.


HC-SR501 Pin Outs and Controls

The pin-outs and controls for this device are shown in the picture below and described in the following table.

HC SR501 Motion Detector Pin Outs


Pin or Control

  • Time Delay Adjust: Sets how long the output remains high after detecting motion…. Anywhere from 5 seconds to 5 minutes.
  • Sensitivity Adjust Sets: the detection range…. from 3 meters to 7 meters
  • Trigger Selection Jumper: Set for single or repeatable triggers.
  • Ground pin: Ground input
  • Output Pin: Low when no motion is detected.. High when motion is detected. High is 3.3V
  • Power Pin: 5 to 20 VDC Supply input

HC SR501 PIR Functional Description

The SR501 will detect infrared changes and if interpreted as motion, will set its output low. What is or is not interpreted as motion is largely dependent on user settings and adjustments.

Device Initialization

The device requires nearly a minute to initialize. During this period, it can and often will output false detection signals. Circuit or controller logic needs to take this initialization period into consideration.

Device Area of Detection

The device will detect motion inside a 110 degree cone with a range of 3 to 7 meters.

HC SR501 View Area

PIR Range (Sensitivity) Adjustment

As mentioned, the adjustable range is from approximately 3 to 7 meters. The illustration below shows this adjustment.


Time Delay Adjustment

The time delay adjustment determines how long the output of the PIR sensor module will remain high after detection motion. The range is from about 3 seconds to five minutes. The illustration below shows this adjustment.


3 Seconds Off After Time Delay Completes – IMPORTANT

The output of this device will go LOW (or Off) for approximately 3 seconds AFTER the time delay completes. In other words, ALL motion detection is blocked during this three second period.

For Example:

Imagine you’re in the single trigger mode (see below) and your time delay is set 5 seconds.
* The PIR will detect motion and set it high for 5 seconds.
* After five seconds, the PIR will sets its output low for about 3 seconds.
* During the three seconds, the PIR will not detect motion.
* After three seconds, the PIR will detect motion again and detected motion will once again set the output high and the output will remain on as dictated by the Time Delay adjustment and trigger mode selection.

Trigger Mode Selection Jumper

The trigger mode selection jumper allows you to select between single and repeatable triggers. The affect of this jumper setting is to determine when the time delay begins.

  • SINGLE TRIGGER – The time delay begins immediately when motion is first detected.
  • REPEATABLE TRIGGER – Each detected motion resets the time delay. Thus the time delay begins with the last motion detected.


Connect Your Arduino to the HC-SR501

This only requires three wires.

Sketch PIR_Motion_Detector.ino

The sketch simply turns on Your Arduino LED connected to Pin 13 whenever motion is detected.

Be sure to beware of and somehow handle the 1 minute initialization in whatever application you develop.

// HC-SR501 Motion Detector
// Sample Sketch

int ledPin = 13;  // LED on Pin 13 of Arduino
int pirPin = 7; // Input for HC-S501

int pirValue; // Place to store read PIR Value

void setup() {

  pinMode(ledPin, OUTPUT);
  pinMode(pirPin, INPUT);

  digitalWrite(ledPin, LOW);


void loop() {
  pirValue = digitalRead(pirPin);
  digitalWrite(ledPin, pirValue);


PIR Sensor Circuit without Arduino

PIR1_Fritzing Sketch-without-Arduino

Leave a Reply