Enter your sensor's Time of Flight and ambient Temperature (or toggle Use Custom Speed of Sound to set your own Speed of Sound), and the Ultrasonic Distance Calculator gives you the Distance to Object along with Distance in meters, Sound Velocity, and One-Way Travel Time.
Distance to Object
--
Distance (meters)
--
Sound Velocity
--
One-Way Travel Time
--
Temperature directly affects the speed of sound in air. At 20°C, sound travels at approximately 343 m/s, but this increases by about 0.6 m/s for each degree Celsius rise. Accurate temperature compensation is crucial for precise distance measurements.
The ultrasonic sensor measures the total time for the sound wave to travel to the object and back to the sensor. Since we want the one-way distance to the object, we divide the total time by 2 to get the actual distance.
Most common ultrasonic sensors like the HC-SR04 have a range of 2cm to 400cm (4 meters). However, accuracy decreases at maximum range due to signal attenuation and environmental factors.
Under ideal conditions, ultrasonic sensors can achieve accuracy within ±3mm. However, factors like temperature variations, humidity, air currents, and object surface properties can affect accuracy.
Hard, flat surfaces perpendicular to the sensor provide the best results. Soft materials like fabric or foam can absorb sound waves, while angled surfaces may reflect the signal away from the sensor, causing inaccurate readings.
Yes, but outdoor conditions like wind, rain, and temperature variations can affect accuracy. Wind can alter sound wave propagation, while rain droplets can cause false readings. Proper housing and calibration are important for outdoor use.
Most ultrasonic sensors have a minimum distance (blind zone) of about 2-3cm. This is due to the time needed for the sensor to switch from transmit to receive mode and the physical limitations of the transducer.