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HC-sr505: A Complete Guide

An HC-SR505 sensor is an essential module in security systems that enables automatic controls. Thus, for an elaborate explanation of this module, check out our guide. At OurPCB, we have all you need to know about the module. We'll expound on its functions, pin configuration, how to use it, applications, and interfacing with Arduino-Uno.  

What is an HC-SR505?

Led projector with motion sensor

Fig 1: Led projector with motion sensor

  You can consider it as a pyroelectric motion sensor. Primarily, it detects the movement of objects that emit infrared radiations. Note, emission of heat energy is a characteristic of bodies with more than absolute zero temperature. Thus, this serial monitor will identify the changes in the latent infrared radiations.  

HC-SR505 Pin Configuration

Motion detector attached on a blue wall

Fig 2: Motion detector attached on a blue wall

  It features three pins, as illustrated in the table below:  

HC-SR505 Features

Motion sensor

Fig 3: Motion sensor


How to use HC-SR505 Sensor

  The connection process is also straightforward. You can link this Sensor to any electronic system where a motion sensor module is necessary. Just set it to a low-power operation mode, and you'll receive a signal. For an in-depth understanding, consider this simple application circuit:  

Fig 4: A HC-SR505 Sensor Application Circuit


Circuit Explanation

  • The circuit above is connected to a DC power source of +5V.
  • As illustrated, you need to connect the device response to an LED. Essentially, this is to show the output signal.
  • Also, there is a 1K resistor whose aim is to limit the device's current output.

Working Principle

Consider the above movement sensor connected to a DC power supply and the lens facing a wall. In such a case, the actual Sensor will not detect any change of IR radiation. Thus, the output pin will indicate low logic, and the LED will remain off. If a human passes near the module, it will increase IR radiation. In turn, there'll be high logic on the output pin. Thus, the LED will turn on, indicating the presence of an object. Therefore, through this technique, a batch of sensors can identify the motion of objects. As a result, it is common in almost all battery-power automatic control products.  

What can I use instead of an HC-SR505?

A Motion Sensor on a white background

Fig 6: A Motion Sensor on a white background

  If you do not have the HC-SR505 Motion Sensor Module, you can use the HC-SR01. It is also an example of an effective infrared technology-based motion sensor.  

Interfacing HC-SR505 with Arduino

You can create Arduino-Uno programming sensors using this component. All you need is to make the right connections. As highlighted earlier, the HC-SR505 features three pins. Thus, it would help connect the module's ground pin to the Arduino's ground. Next, connect the signal pin of the HC-SR505 to any of the Arduino's digital pins. Also, you'll need to input the following code to the Arduino:  

Fig 7: An Arduino Code for Use with the HC-SR505

  Lastly, attach an LED between the digital pin and the signal pin. It'll help showcase the module's operation.  


Surveillance camera with motion sensor.

Fig 8: Surveillance camera with motion sensor.

  • Essential in security systems such as alarms.
  • Useful In industrial control and automation systems.
  • The module is also cardinal in induction toys and lamp manufacturing.
  • Also essential in automatic sensing in theft protection applications.
  • Lastly, the module is necessary for lighting.


From this post, you have seen the significance of the module in automatic sensor applications. It is also easy to incorporate in all systems, as highlighted in the simplified circuit diagram. In case you have any queries about this module, talk to us. We are ready to assist you at any time.