Ultrasonic sensing is one of the best ways to sense proximity and detect levels with high reliability.
Our technical support gets emails all of the time about how our sensors work and what environments our sensors work (or don’t work) in.
This guide was created as an introduction to ultrasonic sensing, it’s principles, and how ultrasonic sensors work in your applications.
At a top level, you need to know what an ultrasonic sensor is…
What is an ultrasonic sensor?
An ultrasonic sensor is an instrument that measures the distance to an object using ultrasonic sound waves.
An ultrasonic sensor uses a transducer to send and receive ultrasonic pulses that relay back information about an object’s proximity.
High-frequency sound waves reflect from boundaries to produce distinct echo patterns.
How Ultrasonic Sensors Work.
Ultrasonic sound vibrates at a frequency above the range of human hearing.
Transducers are the microphones used to receive and send the ultrasonic sound.
Our ultrasonic sensors, like many others, use a single transducer to send a pulse and to receive the echo. The sensor determines the distance to a target by measuring time lapses between the sending and receiving of the ultrasonic pulse.
The working principle of this module is simple. It sends an ultrasonic pulse out at 40kHz which travels through the air and if there is an obstacle or object, it will bounce back to the sensor. By calculating the travel time and the speed of sound, the distance can be calculated.
Why use an Ultrasonic Sensor?
Ultrasound is reliable in any lighting environment and can be used inside or outside. Ultrasonic sensors can handle collision avoidance for a robot, and being moved often, as long as it isn’t too fast.
Ultrasonics are so widely used, they can be reliably implemented in grain bin sensing applications, water level sensing, drone applications and sensing cars at your local drive-thru restaurant or bank.
Ultrasonic rangefinders are commonly used as devices to detect a collision.
Ultrasonic Sensors are best used in the non-contact detection of:
Non-contact sensors are also referred to as proximity sensors.
Ultrasonics are Independent of:
- Material (except for soft surfaces, i.e. wool, because the surface absorbs the ultrasonic sound wave and doesn’t reflect sound.)
Long range detection of targets with varied surface properties.
Ultrasonic sensors are superior to infrared sensors because they aren’t affected by smoke or black materials, however, soft materials which don’t reflect the sonar (ultrasonic) waves very well may cause issues. It’s not a perfect system, but it’s good and reliable.
Applications Involving Ultrasonic Detection:
Ultrasonic Distance Measurement
Distance measurement is based on the measurement of time-of-flight. The time between sending and receiving the reflected sound signal is calculated by the sensor. Ultrasonic distance sensors, like the MB7360 HRXL-MaxSonar-WR, are used in as height monitors, bin level measurement and proximity zone detect.
Popular Sensors for Measuring Distance
Car Detection Sensor
Features of the weather resistant MB8450, Car Detection Sensor, include centimeter resolution, short to long distance detection, range information from 500mm to 5000mm for the nearest detectable target, a ~4Hz read rate, and an easy to use USB interface.
Features of the weather resistant MB7560, SCXL-MaxSonar-WR, include reduced impact of condensation and frost when ran continuously in closed or high-moisture environments, millimeter resolution, short to long distance detection, range information from 300mm to 5000mm for the nearest detectable target, a 0.6Hz read rate, and various output options: pulse-width, analog voltage, and RS232 serial.
- Tank level measurement, Fuel gauging, irrigation control.
- This project for a Low Power Water Level Sensor, from Hackster.io developer Amedee, uses a weather resistant sensor from our WR line. In combination with a LoraWan node and The Things IoT open source network, this project was developed to measure the water level in a rainwater tank. Although, it can be used in many applications.
Popular Sensors for Liquid Level Sensing
Features of the weather resistant MB7052, XL-MaxSonar-WRM1, include small target rejection providing range information to the target with the largest acoustic return, a stability filter, centimeter resolution, short to long distance detection, range information from 20cm to 765cm, a 6.7Hz read rate, and various output options: pulse-width, analog voltage, and RS232 serial.
Features of the weather resistant MB7369, HRXL-MaxSonar-WRM, include millimeter resolution, short to long distance detection, range information from 300mm to 5000mm to the target with the largest acoustic return, a 6.7Hz read rate, and various output options: pulse-width, analog voltage, and RS232 serial.
Ultrasonic Obstacle Detection
- Our UAV Sensors for Drones as well as our proximity sensors that are used for robots are for obstacle detection.
- Ultrasonic sensors are suitable for close range detection up to ten meters and provide multiple range measurements per second.
- Main advantages:
- Low power consumption – can be powered by battery, inexpensively.
- Can operate in many environmental conditions – ultrasonic sensors work in smoke filled environments, where other sensors would fail.
Popular Sensors for UAV Applications
Features of the MB1240, XL-MaxSonar-EZ4, include centimeter resolution, has the highest noise tolerance and narrowest beam width of any sensor in the XL‑MaxSonar‑EZ sensor line, short to long distance detection, range information from 20cm to 765cm, a 10Hz read rate, and various output options: pulse-width, analog voltage, and RS232 serial.
Features of the MB1242, I2CXL-MaxSonar-EZ4, include centimeter resolution, has the highest noise tolerance and narrowest beam width of any sensor in the I2CXL‑MaxSonar‑EZ sensor line, short to long distance detection, range information from 20cm to 765cm, up to a 40Hz read rate, and an I2C interface.
Ultrasonic sensors are a reliable, cost-effective solution for distance sensing, level, and obstacle detection.
Once you understand how ultrasonic sensors work and what ultrasonic technology is perfect for and not so good for, you can make a more educated decision on the right sensor system for your application.
Take a look at our patent pending solution for sensing cargo in 53′ trailers to detect the fullness or absence. Read about the Trailer Cargo Sensor.
Review our product catalog and contact our Technical Support Team by clicking the button below to get help selecting a sensor.