OK ecco il modello del sensore HC-SR04
e queste le specifiche:
Operating voltage: 5V
Operating current: <2mA
Sensor angle: 15 degrees
Range: 2cm - 450cm
Resolution: 0.3cm
Output a 10us HIGH signal to Trigger input to start the detection
Measure the length of pulse received on Echo output to determine distance
Distance is pulse length * speed of sound (340M / S)) / 2
ed i servo sono Micro RC SG90 9G