Ultrasonic Sensor VS Infrared Sensor

Nowadays distance or proximity sensors play a major role in many equipment, projects and even in industrial grade robots. Whether to know if there’s a rock you might trip over on your way, or if there’s an intruder in your backyard or even in the piloting of unmanned vehicles or drones. Diverse applications isn’t it? Kind of makes one realize how crucial an element sensors are in any equipment or gadget it’s present in. Put it to you this way, if RMS Titanic had IR or ultrasonic sensors, the tragic ending could have been highly avoidable. Goes on to show it’s relevance right?

Distance sensors essentially work to estimate the distance between one object to another object or an obstacle. It does this without any physical contact (like say, using a tape or scale), but rather by using an output signal (IR, Ultrasonic waves, etc.) and measuring the change when the signal returns. This measurement can be based on the time taken for the return of the output signal, or the intensity of the returning signal, or a change in the signal’s phase. Now that we know the relevance of this device, let’s discuss the different types available and how they differ. Today we discuss two kinds of distance sensors, the Infrared Sensors and the Ultrasonic sensors and the differences between them.

Ultrasonic Sensors

1. Commonly known as the sonar sensor, it detects the distance from one object to another by emitting high frequency soundwaves. The phenomenon of using sounds to detect object distances is called echolocation and it’s natural phenomena used by animals like dolphins and bats to navigate.
2. Working- Ultrasonic sound waves emitted by an object (transmitter) falls on the target object or obstacle, from which the sound waves are reflected back and the sensor’s receiver picks up the wave. The time taken for the return of the wave is calculated against the speed of sound to determine the distance travelled by it. In the presence of an obstacle this distance will be shorter.
3. The ability of ultrasonic sensors to detect objects largely depends on their shape, size and orientation. In general they are better suited for detection of objects closer to 5mm to 1m although some sensors can detect objects to a maximum distance of 20m.
4. It is unaffected by the presence of light sources like sunlight, fluorescent tubes etc. and works well in dim lit surroundings too.
5. They have a low resolution thus aren’t ideal for the detection of objects with extreme textures, or fast moving targets.
6. Frequency ranges from 20kHz to several GHz and they have wavelengths below 1.9cm or less.
7. Its key areas of applications include, sonar navigation systems, in robots sensors, medical imaging, unmanned vehicles, smart cars and more.

Infrared Sensors

1. IR sensors use IR light waves to detect the target distance or proximity from that of an object. The process of using reflection of light to detect the distance is called triangulation.
2. Working- Infrared light is emitted by a transmitting object which then travels till it hits a nearby object or obstacle from whose surface its reflected off of. In the presence of an object the output light wave is reflected back and is detected by a position sensitive detector (receiver) through which the position or distance of the obstacle is measured.
3. It can sense objects or targets that are closer than 10mm which means that it has a limited measurement range.
4. It is affected by external sources of light like sunlight, fluorescent tubes and other environmental conditions which can distort the light waves emitted and received.
5. Applicable for both daytime and night usage, and they can measure distance to soft objects and objects with complex surfaces easily.
6. Frequency ranges from 430THz to 300 GHz and wavelength falls between 700nm to 1mm.
7. They are typically used in proximity sensors for burglar alarms, TVs, computers, thermometers, monitoring, control applications and distance calculation.

Now that we know the key differences between Ultrasonic sensors and IR sensors, it makes it easier for us to decide which sensor is more applicable to our project effortless and smooth functioning! Choose wisely, peeps and may the light or sound be with you and be the guide your machine needs!