3 to 7 meters (Adjustable via onboard potentiometer)
All matter with a temperature above absolute zero emits thermal energy in the form of infrared radiation. Human bodies radiate infrared light at a wavelength of roughly 9 to 10 micrometers.
For a 3.3V logic system (like an ESP32), you can power the module using the dedicated 3.3V configuration pin instead of the standard 5V input, as described in the previous section.
// Define Pins const int pirPin = 2; // HW-416-B OUT pin connected to Digital Pin 2 const int ledPin = 13; // Built-in Arduino LED // Variables to track sensor state int pirState = LOW; // Start assuming no motion detected int val = 0; // Variable for reading the pin status void setup() pinMode(ledPin, OUTPUT); // Declare LED as output pinMode(pirPin, INPUT); // Declare PIR sensor OUT as input Serial.begin(9600); Serial.println("Warm-up sequence initiated. Waiting for sensor stabilization..."); // PIR sensors require a brief warm-up period (30-60 seconds) to stabilize delay(30000); Serial.println("Sensor active. Monitoring area..."); void loop() val = digitalRead(pirPin); // Read input value from HW-416-B if (val == HIGH) // Check if the input is HIGH digitalWrite(ledPin, HIGH); // Turn LED ON if (pirState == LOW) // Motion just detected Serial.println("--> ALERT: Motion detected!"); pirState = HIGH; else digitalWrite(ledPin, LOW); // Turn LED OFF if (pirState == HIGH) // Motion just ended Serial.println("--> Notice: Motion ended / Area clear."); pirState = LOW; Use code with caution. Best Practices & Troubleshooting hw-416-b pir sensor datasheet
Turning this clockwise increases the detection range (up to ~7 meters). Turning it counter-clockwise decreases the range (down to ~3 meters).
The output stays high as long as continuous movement is detected within the sensor's field of view. Applications for the HW-416-B
The HW-416-B is more than just a motion detector; it is an energy-efficient trigger. While newer, more expensive "radar" sensors (like the RCWL-0516) can detect motion through walls, the HW-416-B remains the reliable workhorse for line-of-sight detection. It is cheap, tunable, and consumes so little power that it might just be the longest-lasting component in your next battery-operated build. 3 to 7 meters (Adjustable via onboard potentiometer)
The HW-416-B is built around the —a highly capable infrared sensing signal processor IC designed specifically for pyroelectric infrared applications.
The is a reliable, low-cost PIR motion sensor perfect for hobbyist and light commercial projects. While you won’t find an official “HW-416-B datasheet” from a major semiconductor brand, the HC-SR501 documentation applies directly . Use the specs and tips above to integrate it into your next motion-sensing project.
Triggering IP cameras or sound alarms when unauthorized entry is detected. // Define Pins const int pirPin = 2;
modules include a jumper to switch between two trigger modes: Non-Repeatable Trigger (L):
If you hold the module with the Fresnel lens facing away from you and the pins pointing downward, the pinout from left to right is generally structured as follows: