Short datasheet, around 78.7 KB, for the HC-SR04 ultrasonic distance sensor module widely used in hobby and educational electronics. It typically lists the operating voltage, trigger and echo pin behaviour, timing of the measurement pulse and the formula for converting echo time to distance. Technicians use it to check whether a module is responding correctly, measuring the trigger pulse and echo output with a scope or logic analyser. Modules from different makers vary slightly, so compare the board markings with the document before assuming identical behaviour.
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