Problems with the jsn-sr04t ultrasonic sensor

I had been testing the jsn-sr04t ultrasonic sensor and everything seemed to be working relatively well. while taking some measurements with my code, i noticed that there were small variations that were not being corrected by the code, so i noticed that there was a kind of potentiometer on the sensor board and decided to try to move it slowly, in an attempt to try some kind of calibration. However, after I performed this test, the sensor stopped showing concrete measurement values and started showing equal values (0 or 22 centimeters) regardless of how far I moved the sensor away from the object. Is there any way to reverse this problem?

That adjustment is a coil. I've not seen a schematic for this version (i.e. single transducer) but the coil is used to boost the power to the transducer.

Do you recall where it was when you started? I've learned to NEVER change a setting without marking the original position.

The below is my (educated) GUESS at how the circuit works:

If you don't have an oscilloscope you will have to move the sensor far away from a good reflector (a wall). Slowly change the coil setting until you get a repeatable (within a couple of counts) reading. Move the sensor further away and repeat the adjustment until no coil setting will make the sensor obtain a reading.

I performed the mentioned tests, including I left marked the position where the component was, however, when returning to the original position (or at least what I believe is the correct position) there was no positive result. Also, I tested changing the position slowly and watching the serial monitor, but I was also unsuccessful. I actually changed the position in a moment and stopped touching the component and then noticed that 1 out of every 8 or 10 values ​​that was displayed on the monitor was showing a correct value, but when trying to move a little more to achieve a calibration the values ​​no longer present this value.

hello @JohnRob

Thanks for your answer, I really appreciate the attention and the amount of detail you gave me. I performed some tests again, including those you also indicated, and I ended up managing to recalibrate the sensor and it is already working correctly.

Best regards, Caio Victor.

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