Contact: Bruce
Tel: +86-755-22 666 190
Fax: +86-755-29 043 136
E-mail: sales@ultrasonic-sensors.net
Skype: longsunac
Address: Room A1, 6/F, Bldg. No. 531, Bagua 3rd Road No. 277, Futian District, Shenzhen, China 518029
4. Ultrasonic distance measuring application
The ultrasonic transmits in the air same velocity as the sound wave does, based on this, we can easily calculate the distance between ultrasonic sensor and the object we detect, while the sound wave speed we can measure by the following formula:
C=331.5+0.607tc (m/s) (1)
tc= temperature (the sound wave speed changes with surrounding temperature)
Principle of distance measuring
Figure 1-1
From above illustration shown on figure 1-1, we can know that the distance measured as follows formula:
D=Ct /2 (2)
't' here it indicates time taking by ultrasonic travels from the transducer to the object and from the object back to the transducer (shown as trigger signal and echo signal), so it equals to t1 plus t2.
From above formula, we can easily calculate the distance "D" if we know the time "t" and temperature "tc" when we test, the ultrasonic speed "C" is available with the formula: C=331.5+0.607tc (m/s).
D=(331.5+0.607tc ) t/2 (3)
Layout of distance measurement system
According to ranging principle, we can design a simple circuit layout of distance measuring system below for reference:
Figure 1-2
