Best way to

[Brian Higgins]

What is the best way to measure Hz (pitch/frequency)?
Brian Higgins
VA Researcher for blind mobility “Laser enhanced Echolocation” ClearPath Navigation


Sent from my iPhone

[James H Phelan]

Brian,

There are several iPhone apps if you just want sound.

If you have access to a microphone or the source is electronic, then an oscilloscope is the way.

There are special frequency spectrum analyzers (often part of the O'scope) that can identify multiple frequencies in a sound.

What is it you want to measure?

James H Phelan
"Nihil est sine ratione cur potius sit quam non sit"
Leibniz

[Sergei Grichine]

Try searching:

"android app to measure sound frequency" (or iPhone) - that's if you want to measure audible sound parameters.

--
You received this message because you are subscribed to the Google Groups "HomeBrew Robotics Club" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hbrobotics+...@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/hbrobotics/77e82d4b-db72-4780-a426-79ae0c978a45%40hal-pc.org.

--

Best Regards,

-- Sergei

[Steven Nelson]

Here is an Arduino sound detector project.

https://projecthub.arduino.cc/lbf20012001/audio-frequency-detector-d300e3

Inspection time: The period of time required to inspect a recently welded piece of metal using your bare hand.
The hotter the metal the shorter the period of inspection time

To view this discussion visit https://groups.google.com/d/msgid/hbrobotics/CA%2BKVXVPcxa32qgR2ZLo55jFUsPfHvF1SajS5G6foPmyN828QZg%40mail.gmail.com.

[Brian Higgins]

I’m trying to create the best sound from my LiDAR sensor for the blind.  I have a couple of apps but it is difficult to get exact measurements, how much is 

Brian Higgins

VA Researcher for blind mobility “Laser enhanced Echolocation” ClearPath Navigation 

Sent from my iPhone

On Sep 21, 2025, at 10:59 AM, Steven Nelson <teamki...@gmail.com> wrote:



To view this discussion visit https://groups.google.com/d/msgid/hbrobotics/CAOSZ7XQjs_gcgvZVSfvfgzdQsQn6P-tJRRgLqfAiRHofUP47Vw%40mail.gmail.com.

[Chris Albertson]

You can find a phone app if all you need is a quick way to measure. But you might be asking how to design a device to do the measurement. The usual way is to sample a microphone then apply an FFT to create a spectrum, then look for the peak.

Most sounds are not pure sine waves but a mix of several with a fundamental and some harmonics. Note that a flute and a piano sound different, even if they play the same note (pitch)

> --
> You received this message because you are subscribed to the Google Groups "HomeBrew Robotics Club" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to hbrobotics+...@googlegroups.com.

> To view this discussion visit https://groups.google.com/d/msgid/hbrobotics/837337AA-1137-4E59-9A02-A61134BDD1A4%40gmail.com.

[cmay...@gmail.com]

Hello Brian,

Years ago I did a project that used stereo images to find objects and create virtual sounds overlaid in 3D space to represent their location for the blind.

LIDAR will have different info, but some of the same ideas may be useful.

Measuring a sounds wasn't as important as generating them, and simple things are fairly obvious - frequency as a function of size, harmonic signatures for related things (poles and posts have a similar sound, easy to distinguish from other fatter or moving objects, can even distinguish color...). Creating the 3D location was fairly easy with simple l/r phase shifting and equalization. I never got into the whole HRTF thing, as it's really not needed.  Contact me privately if you want to talk more in detail.

- Chris M.

[Sergei Grichine]

If you want to play with a DIY device that takes a sample from an I2S microphone, performs FFT and displays results on a small OLED screen, here is a starting point:

https://github.com/slgrobotics/Misc/tree/master/Arduino/Sketchbook/ESP32_AudioFFTMono

https://youtu.be/gvMlcGusZaM

Note the credits to the original code:

/*
 *  Spectrum display of audio signal on 128x64 OLED
 *  The board uses ESP32 DevKitC V4. The library is ArduinoFFT.h
 *  Original code: 2022/06/03 http://radiopench.blog96.fc2.com/blog-entry-1184.html
 *  Modified Oct 2022 by Sergei Grichine for mono operation and ESP32
 *  
 *  Calibration: https://onlinetonegenerator.com/
*/ 

To view this discussion visit https://groups.google.com/d/msgid/hbrobotics/634A1C5C-2F08-43A2-9338-0A44D542E683%40gmail.com.