Difference between Ultrasonic Distance Sensor and Infrared Sensor

With the development of science and technology such as electronic computers, production automation, modern information, military, transportation, chemistry, environmental protection, energy, marine development, remote sensing, and aerospace, the demand for sensors is increasing day by day, and their application fields have penetrated into various industries and in people's daily cultural life. Selecting sensors in these applications can be challenging for any project. The performance of the system depends heavily on the reliability of the sensors and other components of the application.

In order to determine the right sensor for a project's application, there are a few factors to consider in sensor selection.

1. Accuracy: how close the reading is to the true distance.
2. Resolution: The smallest reading or reading change that can be reported.
3. Precision: The smallest reading that can be read repeatedly and reliably.

So what are the differences between ultrasonic distance sensor and infrared sensor?

Ultrasonic distance sensor working principle

Ultrasonic distance sensors work by reflecting sound waves and are used to measure distances. A sensor can detect other people nearby and an ultrasonic distance sensor emits sound waves, which are reflected back if there is an object in front of them. Sensors detect these waves and measure the time between sending and receiving these sound waves. The distance is then estimated from the time interval between the sensor and the object.

Ultrasonic distance sensors are largely insensitive to obstructing factors such as light, dust, smoke, mist, vapor and lint. 

Ultrasonic is not as good as infrared when it comes to defining the edges of an area. Ultrasonic distance sensors are used for level measurement, object detection, distance measurement, anti-collision detection and pallet detection, etc. Ultrasonic distance sensors are used to improve operational efficiency and provide additional safety in manufacturing facilities. This is one of the major factors driving the demand for ultrasonic distance sensors globally.

Infrared sensor working principle

Infrared sensors work by reflecting light waves. Infrared light is reflected from objects or emitted from infrared remote controls or beacons. Infrared sensors are also used to measure distance or proximity. The reflected light is detected, then a distance estimate between the sensor and the object is calculated.

Infrared sensors cannot work in the dark while ultrasonic distance sensors can work in dark environments. Infrared is easier to detect brighter surfaces than dark surfaces because the sensor does not detect darker surfaces. Infrared sensor values ​​typically fluctuate under changing lighting conditions. When objects pass through that range, light waves detect those objects and reflect their presence back to the sensor. Their wavelengths are smaller than those of microwaves. While they are able to detect motion, they can also measure the heat dissipation of an object.

To sum up, the choice of sensor is entirely up to your application. Infrared sensors have many limitations, such as not being able to use them in sunlight due to interference. It can make outdoor applications or dark indoor applications very difficult. Ultrasonic distance sensors work using sound waves and detect obstacles independent of many factors. If reliability is an important factor in your sensor selection, ultrasonic distance sensors are more reliable than infrared sensors. If you are willing to reduce the cost of reliability, infrared sensors are ideal for your application.