Sensors are small devices that are used in other bigger devices. They detect events as well as changes in the environment and send this information to other devices that need the information. Sensors are everywhere and they are part of everyday life.
They are typically not seen and this is not because they are invisible or too tiny for the eye. It is because usually, they are used as parts in other gadgets and devices. You will find them in the home and at the office.
They are used in a variety of applications and everyday objects like automobiles, airplanes, lighting applications, healthcare and housing. They are used in cleaning devices, touch-sensitive buttons like remote controls, image sensing devices and so on.
A good illustration of these is modern cars that are equipped with sensors that stop them from collisions. Some motion-detecting lights and cameras are activated when someone enters a space.
All in all, they help to make life easy and enjoyable. Sensors work in a variety of ways and one of these is by using ultrasonic waves. You can check out the article here to learn more about them.
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What Are Ultrasonic Sensors
These are electronic devices that measure the distance of an object by discharging ultrasonic waves. These sound waves are reflected from the object then it is converted into electric signals. These type of sensors measure distance by using the time difference between when the waves were emitted and when it was received.
Ultrasonic sensors called transducers typically emit a chirp that is between 23 kHz and 40 kHz. The waves travel much faster than the speed of sound that can be heard by the human ear. The human ear can only hear waves at 20 kHz.
Typically, ultrasonic waves have two key components. These are the transmitter and the receiver. The transmitter emits sounds through piezoelectric crystals or an electrostatic technology. The receiver encounters the sound after it has traveled to and from the object.
The speed of sound in the air and at room temperature is 343 m/s. This time can easily be converted to a distance for the object that is being sensed. Keep in mind that the chirps travel to and fro the target object. These can be illustrated in this equation:
Distance = time elapsed * 343/2
The unit of distance is in meters, time is in seconds and speed of sound is in meters/second. These units can be changed to suit specific applications.
How Ultrasonic Sensors Work
Ultrasonic sensors own a large section of the sensing market because of their capabilities, flexibility as well as low cost. They have been around for many decades and are used in drones, robots, autonomous vehicles and so on.
In most standard configurations, the transmitter and receiver are placed side-by-side and as close together as possible. With this, sound waves travel in a straight line to the target and back to the receiver. This in turn yields small errors in measurement.
In some configurations, both the transmitter and receiver are integrated into one unit and this helps to minimize errors. The waves that are emitted from the transmitter are similar to light emanating from a flashlight. It spreads and therefore the beam angle needs to be put into consideration.
This means that as the wave travels farther, the detection area grows vertically and laterally. This is why these sensors measure their coverage in beam angle or beam width. It is recommended that the full angle or the variation angle from the straight line is used when comparing between manufacturers.
Note however that the narrower the beam, the greater the detection range. This is because the ultrasonic pulse energy is better focused and this can go farther before it dispels into unusable levels. A wider beam on the other hand spreads in an arc and this reduces its expected range.
Of the two, the more ideal type of beam to use is dependent on the application where it is needed. Wide beams are great for general detection and covering large areas. The narrow ones limit the detection area and are more direct and therefore prevent false positives.
What Are The Strengths of Ultrasonic Sensors?
Ultrasonic sensors have their capabilities and this can be seen in certain applications and situations. They are typically not affected by the shape, color, or surface texture of the target object. They can even be used to detect glass or water.
They are able to detect objects as near as a few meters and up to about five meters. Some can even be configured to measure up to 20 meters. They are precise, reliable and typically yield consistent results with minimized error. They also have quick refresh rates and can make several measurements within a second.
Furthermore, they are resistant to acoustic as well as electrically noisy surroundings. This is especially true when using those that are furnished with encoded chirps. They are also not expensive as they are made with readily available materials.
What Are Their Weaknesses?
Ultrasonic sensors use sound for measuring distance but the speed of sound can be affected by humidity and temperature. This in turn can affect the precision of their measurement and because of this, they do not work in a vacuum.
Also, they only detect the distance of the target but cannot provide information about the location or its features. They are susceptible to dirt, ice and can get wet and this can make them non-functional. Additionally, although they are relatively small, they may not fit into embedded or very small devices.
Common Applications
Ultrasonic sensors are applicable in many industries. Some of their applications are:
- Industrial Level control
- Agriculture
- Heavy equipment
- Production line sensing
- Robotics
- Distance measurement
- Proximity detection
- Liquid level sensing
- Presence detection.
Another creative way of using them is to control pests and scare off animals. This is because animals typically can hear the range of sound that a transmitter produces. You can learn more and see various ways they are used by visiting the SensComp website.
Conclusion
Ultrasonic sensors are tiny devices but they do important work and help to make processes simpler. They are applicable and relevant in a lot of industries. They are also versatile and reliable. This means you can use them in your products to achieve a high level of success.
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