understanding sensors

Sensors are all around us and they are used around the world. All the many automation we enjoy today is only possible because of these often tiny pieces of technology. Thanks to them, we have lights that turn on when they detect our presence and rooms that can automatically adjust the temperature.

They have birthed fire and smoke detectors, and because they exist, using our garages has become less of a hassle since our garage door now opens as our car draws near to it. Listed here are only a fraction of the many automation that the invention of these electric devices has made possible.

Classification of Sensors

Sensors are categorized in several ways. Below are some of the ways they can be classified:

  • Based on means of detection, e.g., radioactive, biological, electric, etc.
  • Based on the conversion phenomenon
  • Analog and digital
  • Active and passive

Types of Sensors

There are different types of sensors used commonly today for various applications. They measure things like resistance, heat transfer, distance, conduction, capacitance, and so on. They include:

  • Ultrasonic
  • Temperature
  • Infrared (IR)
  • Light
  • Proximity
  • Touch
  • Smoke, alcohol, and gas
  • Pressure
  • Color
  • Strain and weight
  • Humidity
  • Tilt
  • Accelerometer
  • Position
  • Sound
  • Magnetic
  • Flow and Level Sensors. Click here to learn more about infrared.

Ultrasonic Sensors

Ultrasonic sensors are used all around the world, both indoors and outdoors, and in extreme conditions. They have a wide range of applications and that is why so many systems, machines, devices have them.

They are used to measure distance using ultrasonic waves. Basically, the head of the sensor sends out an ultrasonic wave or a high-frequency sound to a target which reflects the wave. The sensor receives this reflected wave and by measuring the time taken between the wave emission and reception, it determines the distance of the object from its own position.

The targets being hit with waves can have any form; they may even be round. That said, there are certain factors that may affect efficiency. Some of these factors include temperature changes, humidity, the roughness of the reflective surface, and surface angle.

How Does it Work?

The principle behind these sensors is simple as has been explained above. The sensor sends a pulse out which travels through the air to the target. Once it hits an object or obstacle (the target), the wave bounces back to the sensor. The distance between it and the object can then be determined by calculating the time-lapse between emission and reception.

Ultrasonic sensors can detect objects regardless of variables like material, surface, or color. However, it won’t be able to detect materials that are soft. Wool is one of such materials as it is soft and will absorb the wave rather than reflect it back to the source. Unlike infrared sensors that struggle to detect translucent objects, ultrasonic sensors excel in this area as well. Installing this type of sensor can be tricky and should be done by professionals. You can visit SensComp Sensor Solutions to know how to identify providers who have extensive industry knowledge and experience.

Types of Ultrasonic Sensors

There are two main types, which are:

  1. Proximity Detection: These are used to monitor a given area and they alert the user when an object is detected within that specified area. Ultrasonic sensors are primarily used for this application because unlike others, they can detect objects irrespective of reflectivity, material, or size.
  2. Ranging Measurement: This is used to measure the displacement or distance of an object moving towards or away from the ultrasonic sensor.

These two types are further broken down into different categories. They are intrinsically safe, self-contained, close range, and high accuracy ultrasonic sensors.

understanding sensors2

Avoiding Disruption When Using Multiple Sensors

When more than one sensor is used in an application, it is crucial that they be connected in such a way as to avoid interference issues like crosstalk. To prevent the disruption of signals, ensure the surface of the sensor or transducer is clear of any obstructions. Things like ice, dirt, and snow are common obstructions that should be dealt with.

For applications where the sensor in use may be exposed to obstructions like snow or ice, you can get a self-cleaning sensor that cleans off any moisture to function effectively. This type of sensor is specifically designed for high-moisture environments.

Why Choose an Ultrasonic Sensor?

There are several reasons to pick this sensor over others. Ultrasound works effectively in different lighting conditions and so, can be used inside and outside. Because it can handle being moved often, it can be used on robots to avoid the collision. However, for it to function properly, it shouldn’t be moved around too fast.

An ultrasonic sensor has a wide range of applications. It can reliably be used by drive-thru restaurants and banks. It also works great for water and grain sensing, and drone applications. They are also commonly used for non-contact detections of level, distance, position, and presence. Finally, an ultrasonic sensor is independent of smoke, light, color, dust, and materials, except soft surfaces like wool.

Disadvantages of Ultrasonics

While ultrasonics work for different situations, they should not be used for target objects that are too small. This is because object detection will be difficult since the reflected signal may be insufficient and may lead to an incorrect measurement of distance.

Ultrasonics will not function properly when there are noises on the same frequency at which they have been set to operate. Noises like whistle sounds, the hissing of valves, or compressed air are all enough to affect the efficiency of ultrasonics.

It is unable to detect objects close to its face because of what is known as “ringing”. When the transducer emits a wave, it continues to vibrate, this continued vibration is what is known as ringing. Because of this ringing, the sensor will not detect objects within its “dead zone” (the area closest to the transducer) because the energy must disperse before it can listen for an echo.


While the application of ultrasonics is broad, they may not be suitable for situations that require quick detection as they aren’t as fast as photoelectric sensors. A photoelectric sensor uses light and since the speed of light is faster than that of sound, it is much more responsive than an ultrasonic sensor.