A basic ultrasonic distance sensor measures distance using sound waves through a process called "echolocation." This technology is inspired by the way bats navigate in the dark by emitting high-frequency sound waves and then detecting the echoes that bounce back from objects in their surroundings.
Here's how a basic ultrasonic distance sensor works:
Emission of Ultrasonic Waves: The sensor emits a short burst of high-frequency ultrasonic sound waves, typically in the range of 20 kHz to 200 kHz. These sound waves are beyond the range of human hearing.
Propagation of Sound Waves: The emitted sound waves travel through the air at a speed of around 343 meters per second (at room temperature). The sensor measures the time it takes for the sound waves to travel to an object and return as an echo.
Reflection from Objects: When the emitted sound waves encounter an object in their path, they are reflected back towards the sensor. The time it takes for the sound waves to travel to the object and return is directly related to the distance between the sensor and the object.
Detection of Echo: The sensor's receiver detects the returning echo of the emitted sound waves.
Time Measurement: By measuring the time interval between the emission of the sound waves and the reception of their corresponding echoes, the sensor can calculate the time taken for the sound to travel to the object and back.
Distance Calculation: Using the speed of sound in air and the measured time interval, the sensor calculates the distance to the object. The formula used is:
Distance = (Speed of Sound × Time) / 2
Dividing by 2 accounts for the round-trip travel of the sound waves.
Output: The calculated distance is then typically provided as an analog or digital output by the sensor. This distance information can be used by microcontrollers, computers, or other devices for various applications such as object detection, obstacle avoidance, robotics, industrial automation, and more.
It's important to note that the accuracy of ultrasonic distance sensors can be influenced by factors like temperature, humidity, and the reflective properties of the objects being detected. Additionally, some advanced ultrasonic sensors can incorporate multiple transducers for improved accuracy and wider detection angles.