SunFounder PiDog, Manual

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SunFounder PiDog Kit, Release 1.0
• Max Range: 500cm
• Min Range: 2cm
• Trigger Input Signal: 10uS TTL pulse
• Echo Output Signal: Input TTL lever signal and the range in proportion
• Connector: XH2.54-4P
• Dimension: 46x20.5x15 mm
Principle
The basic principles are as follows:
• Using IO trigger for at least 10us high level signal.
• The module sends an 8 cycle burst of ultrasound at 40 kHz and detects whether a pulse signal is received.
• Echo will output a high level if a signal is returned; the duration of the high level is the time from emission to
return.
• Distance = (high level time x velocity of sound (340M/S)) / 2
Formula:
• us / 58 = centimeters distance
• us / 148 = inch distance
• distance = high level time x velocity (340M/S) / 2
Application Notes
• This module should not be connected under power up, if necessary, let the module’s GND be connected first.
Otherwise, it will affect the work of the module.
• The area of the object to be measured should be at least 0.5 square meters and as flat as possible. Otherwise, it
will affect results.
3.7. Ultrasonic Module 99