I want to use my ultrasonic sensor on the Core. I have used it before on arduino. I tried to use an old arduino script, but it seems that pulseIn() is not recognized in the core. Where can I find example code ?

Hi @Jack See this thread for some details: [image] pulseIn Function - Version 0.1 (Beta) Firmware **Current Version: 0.1.1 (Beta) 01/23/2014 ** Previous Version: 0.1 (Beta) Here’s my first real version of a pulseIn() function for the Spark Core. Due to the blocking nat…

Hi @Jack , You can find the library and sample code for Ultrasonic rangefinder in the web ide (Particle Build). Just go to libraries and search for “HC_SR04” . Hope this helps. web Ide

@VigneshA , yes, that was a big help. I tried it, and it seems to be working as well as can be expected of an ultrasonic sensor. I will add some averaging to the results, and may prevent it from jumping around so much. I have tested it on the work bench, but not yet with water. I am not sure how well…

You can also try to use a float on the water, of wich the ultrasonic can bounce. Might help.

Thanks Moors7, I will try that if the water surface does not provide enough accuracy.

@Jack , I ported and tried @timb ’s pulseIn code and it totally unreliable and unusable IMO.

Thanks @peekay123 , for checking the pulseIn() code out. I have since found an example, and library for Ultrasonic Sensor for the Core. @VigneshA pointed me to the HC_SR04 in the library, and I am testing it today with good results.

@peekay123 , my ultrasonic sensor is putting out readings all around. I need a good averaging calculation, to average like the last 25 readings. How is a good way to do that?

@Jack , two ways. One, accumulate 25 readings and divide by 25. Or, do a rolling average where you take the first two readings, add them and divide by 2. On the third reading, add it to the previous average and divide by 2 and so on. The first requires 25 readings before you get an average. The s…

Oh, I think I see. the rolling average is really a weighted average, giving more weight to the most recent reading, rather than a flat average of the last 25 readings. Actually it does not take into account 25 at all. That may be the best, since my water level will change fairly slowly. The hc_sr04…

Ultrasonic Sensor, pulseIn() [SOLVED]

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bko June 2, 2015, 2:53pm 2

Hi @Jack

See this thread for some details:

Searching for pulseIn is how I found this again.

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Ultrasonic Sensor, pulseIn() [SOLVED]

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