- Use voltage: DC5V
- Static current: Less than 2mA
- Level output: High-5V
- Level output: Low 0V
- Sensor angle: Not more than 15 degrees
- Detection distance: 2cm-450cm
- High precision: Up to 3mm
- VCC 5V power connection
- Trig (control side) connected microcontroller IO port
- Echo (receiving end) connected microcontroller IO port
- GND Ground Ground
The principle of ultrasonic distance measurement
Ultrasound is a relatively high frequency sounds, the strong point of ultrasonic distance measurement is the use of ultrasonic wave propagation velocity in air is known, measuring wave reflected by an obstacle encountered after the launch back in time, according to the transmitting and receiving The time difference calculating the emission point of the actual distance to the obstacle. Thus, the principle of ultrasonic distance measurement principle is the same with the radar.
Ranging of formula: L = C*T
Where L is the length of the distance measurement; C of the ultrasonic propagation velocity in air; T for measuring the distance the propagation time difference (T is transmitted to the receiving time half the value).
Known ultrasonic velocity C = 344m / s (20 C ambient temperature)
Ultrasonic propagation velocity error
Ultrasonic propagation velocity affected by the density of the air, the higher density of the air, the faster the ultrasonic wave propagation, and the density of the air temperature has a close relationship with the approximate formula: C = C0 +0.607 * T C
Where: C0 is zero when the acoustic velocity 332m / s;
T is the actual temperature (C).
For ultrasonic ranging accuracy required to achieve 1mm, we must take the ambient temperature of the ultrasonic propagation into account.
Fourth, the module works
(1) The IO trigger distance, high-level signal to at least 10us;
(2) the module automatically sends eight 40khz square wave, automatically detects whether a signal return;
(3) a signal back, through the IO outputs a high level, high duration is Ultrasonic time from launch to return. Test distance = (time * High speed of sound (340M / S)) / 2;
Fifth, the module uses the method
A control port made a high of more than 10US, you can wait to receive high output port. One has
Output can open the elapsed timer, when this port goes low when you can read the timer value, this time on the time for this distance, only calculate the distance. This constant cycle of measurement, you can reach your The value of the mobile