How do I accurately measure

[Brian Higgins]

How do I accurately measure frequency of the sound of my LiDAR smart cane for the blind?
Brian Higgins
VA Researcher for blind mobility “Laser enhanced Echolocation” ClearPath Navigation


Sent from my iPhone

[Chris Albertson]

Lidar uses light, not sound.

But if you are using an ultrasound sensor, not Lidar, the best way to know the frequency is to read the data sheet for the sensor. It will be there, and you should not have to measure. (It will be somewhat above 20,000 Hz.)

OK to directly answer the question. There are phone apps for measuring sound, but ultrasonic might be much higher than the phone can measure. The cheapest way might be to pause the electric signal that is going into the transducer and assume this is the same frequency as the sound the transducer emits. (Could be a wrong assumption, but the transducer’s data sheet will make this clear.) Directly measuring the sound is going to be expensive as most microphones and consumer-level amplifiers don’t work with ultrasound. But you can try…. Aim the sensor at a good microphone and look at the mic’s output on an oscilloscope. Many digit scopes have the ability to measure frequency.

In short, you can look this up, no need to measure.

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[Craig Austin]

Not sure, but I suspect Brian is referring to an audible signal that his cane emits when the lidar detects an obstacle. If that's the case, then a little more info would be very helpful. Brian, what component are you using to produce the sound? I suspect you're not using a speaker?

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[Brian Higgins]

Sorry I use a pizeo speaker that is where the audio comes from 

I would like an accurate reading the manufacturer is trying to replicate the sound I created . I used a decibel meter for the volume but would like the best frequency measurement possible 

Brian Higgins

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

Sent from my iPhone

On Jan 26, 2026, at 3:08 PM, Craig Austin <agu...@gmail.com> wrote:



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[Craig Austin]

I think the easiest approach may be to connect a microphone to any audio instrument (such as a tape recorder) capable of driving/receiving the microphone then using an oscilloscope to measure the waveform across the microphone. The challenge with that is that you may have multiple frequencies. I'm interested in hearing what others have to say.

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[David Murphy]

I'm not certain this world be accurate, but If you are trying to get the fundamental, then a guitar tuner or tuner app might due

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[Chris Albertson]

Oh, an audible tone.  That is much easier.     I have an iPhone app that will record an audio sample and then apply an FFT to get a spectrum.      I just tested it and it does well.  But most sounds are not a pure tone, there will be a peak and possibly some harmonics.    The FFT display will show you.      The name of the app I used is “Sound Spectrum Analysis” but there are a few others like it..  It has all kinds of settinf like thew size of the FFT and sample rate but the defaults should work.   I’m pretty sure the app is free.

If you have a PC or Mac or Linux, I am pretty sure “Audacity” will do the same.   It is free as well.  Google will find it

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[Ed Okerson]

There is an android app called Spectroid that is a nice audio spectrum analyzer.

Ed Okerson 

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