Hi to all! I have been using the ultrasonic sensor HC-SR04 for a while. I was puzzled to read in most pages that people were happy with them because my experience was mixed. Now I am planning to use them for a project where I need to know more about their specifications, so I have run some domest…

Hello RiGonz This looks like a thorough and useful piece of work. Thank you for doing it. A couple of questions: From the pictures, it looks like the testing was carried out at floor level on a hard floor surface. Do you think this had any effect on the low vertical FOV you measured? Could y…

Hi, Ray & Thanks for the feedback! I have uploaded the sketch (pretty simple, in any case) and one of the spreadsheets that I have used to handle the data of each measurement (all are the same, only the data changes). Links (code for the sketch is also included below): Box (spreadsheet) and Box (s…

Having spent a lot of time on this myself, I would suggest the following... First, your calculation of the speed of sound is incorrect and you probably shouldn't be dividing by 10,000 for your speed of sound variable. The reason is that float is only accurate to 6-7 decimal digits of precision and …

Thanks a lot, Tim - I promise that I'll never ever write again that a sketch is "pretty simple"... :slight_smile: The typo in the sound speed expression is quite probably the cause of the large absolute errors that I "observed". Regarding the room temperature, I checked it and was 23-24ºC - as yo…

RiGonz: Thanks a lot, Tim - I promise that I'll never ever write again that a sketch is "pretty simple"... :slight_smile: The typo in the sound speed expression is quite probably the cause of the large absolute errors that I "observed". Regarding the room temperature, I checked it and was 23-24…

Hi again on the tests for the HC-SR04... I have fixed the errors spotted by Tim (thanks once again) in the sketch and even managed to work it all without float variables ( :fearful:); and redone the tests with the assistance of my youngest daughter :% As per my measurements the facts regarding the…

Briefly tested HC-SR04 before reading RiGonz comprehensive review. Same conclusion: precision is not near enough of datasheet. Test distance near 25 cm results in min-1449 max-1483 milliseconds response with 1459 median. Which means 2.5% precision. Typical measurement pattern is like 1456-1456-145…

Hi, I added some of this information to the ArduinoInfo.Info page HERE:

Hey RiGonz, I am actually trying to conduct the same experiment, since I need to know the probability distribution of the measurement error. I came up with quite a few measurements already, and I have observed: The measurement error doesn't seem to be Gaussian distributed. This is somewhat weird, i…

HC-SR04: tests on accuracy, precision and resolution of ultrasonic measurement

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HC-SR04: tests on accuracy, precision and resolution of ultrasonic measurement

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