HC-SR04 doesn't seem to work with Arduino Uno pins 1 to 6

Other Hardware Sensors
1

I'm not sure what I should try to do next in order to resolve the following problem. Suggestions will be greatly appreciated.

I have a device with three HC-SR04 Ultrasonic Sensor Distance Modules connected to an Arduino Uno. The echo and trigger are connected to pins 1 to 6. The distance reported is zero for all detectors.

However, when I connect trig/echo from each detector to pins 12 and 13, the detectors provide a reasonable distance. I tested all the detectors and their associated wires. So, the detectors and wires are not defective.

To make sure the pins are working, I connected each to a LED/resistor and did a digitalWrite to HIGH and LOW. The LEDs blinked for pins 1 to 6. I did not test digitalRead.

The documentation for pulseIn does not describe any pin limitations.

There are sample sketchbooks that use pins other than 12 and 13, so I am assuming that pins 1-6 should work with the detectors. Is this assumption incorrect?

Suggestions for next steps will be greatly appreciated.

2

Pin 1 is not a good choice because it's used for hardware serial communication with the Serial Monitor, which I'm guessing you're using to print out the distance reading. 2-6 should work fine.

Please post your code using code tags (</> button on the toolbar). Maybe someone can spot a code error causing the problem.