Cost performance ratio is excellent. All 3 sensors arrived in good condition. But be aware: The HC-SR04 has a well-known bug (or is this really a feature???): The sensor can stuck after measuring our of range. It delivers zero distance values permanently, even if something is quite close. There is a software workaround: if (distance==0) { pinMode(echoPin, OUTPUT); digitalWrite(echoPin, LOW); pinMode(echoPin, INPUT); } // OR this one if (distance == 0 && digitalRead(ECHO_PIN) == HIGH) { pinMode(ECHO_PIN, OUTPUT); digitalWrite(ECHO_PIN, LOW); delay(100); pinMode(ECHO_PIN, INPUT); } } For more see here: https://forum.arduino.cc/index.php?topic=55119.45 https://bitbucket.org/teckel12/arduino-new-ping/issues/3/hc-sr04-sensor-get-stuck-at-zero

Cost performance ratio is excellent. All 3 sensors arrived in good condition. But be aware: The HC-SR04 has a well-known bug (or is this really a feature???): The sensor can stuck after measuring our of range. It delivers zero distance values permanently, even if something is quite close. There is a software workaround: if (distance==0) { pinMode(echoPin, OUTPUT); digitalWrite(echoPin, LOW); pinMode(echoPin, INPUT); } // OR this one if (distance == 0 && digitalRead(ECHO_PIN) == HIGH) { pinMode(ECHO_PIN, OUTPUT); digitalWrite(ECHO_PIN, LOW); delay(100); pinMode(ECHO_PIN, INPUT); } } For more see here: https://forum.arduino.cc/index.php?topic=55119.45 https://bitbucket.org/teckel12/arduino-new-ping/issues/3/hc-sr04-sensor-get-stuck-at-zero

Cost performance ratio is excellent. All 3 sensors arrived in good condition. But be aware: The HC-SR04 has a well-known bug (or is this really a feature???): The sensor can stuck after measuring our of range. It delivers zero distance values permanently, even if something is quite close. There is a software workaround: if (distance==0) { pinMode(echoPin, OUTPUT); digitalWrite(echoPin, LOW); pinMode(echoPin, INPUT); } // OR this one if (distance == 0 && digitalRead(ECHO_PIN) == HIGH) { pinMode(ECHO_PIN, OUTPUT); digitalWrite(ECHO_PIN, LOW); delay(100); pinMode(ECHO_PIN, INPUT); } } For more see here: https://forum.arduino.cc/index.php?topic=55119.45 https://bitbucket.org/teckel12/arduino-new-ping/issues/3/hc-sr04-sensor-get-stuck-at-zero

Excellent quality product.

Produto de qualidade excelente.

Excellent quality product.