Description
HC-SR501 PIR Motion Sensor Detector Module
The PIR Motion Sensor Detector Module HC-SR501 allows you to sense motion. It is almost always used to detect the motion of a human body within the sensor’s range. It is often referred to as “PIR”, “Pyroelectric”, “Passive Infrared” and “IR Motion” sensor. (Find out a wide range of Sensor at solicstores.in)
The module has an onboard pyroelectric sensor, conditioning circuitry, and a dome-shaped Fresnel lens. It has a delay time adjustment potentiometer and sensitivity adjustment potentiometer. Repeat Trigger Selection Jumper is also available. It is compatible with ARDUINO, RASPBERRY PI, AVR, PIC, 8051, etc.
Pin Configuration
| Pin Number | Pin Name | Description |
| 1 | Vcc | Input voltage is +5V for typical applications. Can range from 4.5V- 12V |
| 2 | High/Low Output (Dout) | Digital pulse high (3.3V) when triggered (motion detected) digital low(0V) when idle(no motion detected |
| 3 | Ground | Connected to the ground of the circuit |
The PIR sensor stands for Passive Infrared sensor. It is a low-cost sensor that can detect the presence of Human beings or animals. This sensor has three output pins Vcc, Output, and Ground as shown in the pin diagram above.
The module can be powered from voltage 4.5V to 20V but, typically 5V is used. Once the module is powered allow the module to calibrate itself for a few minutes, 2 minutes is a well-settled time. Then observe the output on the output pin. Before we analyze the output we need to know that there are two operating modes in this sensor such as Repeatable(H) and Non- Repeatable(L) and mode. The Repeatable mode is the default mode.
The output of the sensor can be set by shorting any two pins on the left of the module as shown below. You can also notice two orange colour potentiometers that can be used to set the sensitivity and time which will be explained further below.
Repeatable(H) mode
In Repeatable(H) mode the output pin Dout will go high (3.3V) when a person is detected within range and goes low after a particular time (time is set by “Off time control” potentiometer). In this mode, the output pin will go high irrespective of whether the person is still present inside the range or has left the area. The sensitivity can be set using the “sensitivity control” potentiometer
Non- Repeatable (L) mode
In “L” mode the output pin Dout will go high (3.3V) when a person is detected within range and will stay high as long as he/she stays within the limit of the Sensors range. Once the person has left the area the pin will go low after the particular time which can be set using the potentiometer. The sensitivity can be set using the “sensitivity control” potentiometer
There are two important materials present in the sensor one is the pyroelectric crystal which can detect the heat signatures from a living organism (humans/animals) and the other is a Fresnel lens which can widen the range of the sensor. Yes, the white color things are just a lens that is used to widen the range of the sensor, if you remove the lens you can find the Pyroelectric sensor inside it covered inside a protective metal casing as shown above.
PIR Sensor Features
- Wide range on input voltage varying from 4.V to 12V (+5V recommended).
- The output voltage is High/Low (3.3V TTL).
- It can distinguish between object movement and human movement.
- Has two operating modes – Repeatable (H) and Non- Repeatable (L).
- Covers distance of about 120° and 7 meters.
- Low power consumption of 65mA.
- Operating temperature from -20° to +80° Celsius.
PIR Sensor Applications
- Automatic Street/Garage/Warehouse or Garden Lights
- Burglar Alarms
- Security cams as motion detectors
- Industrial Automation Control
Package Includes :
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