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How to detect vehicle sound at 100 m distance using microphone and Arduino?

abhishekks

Hello everyone,

I am working on a project where I need to detect the sound of vehicles (cars, heavy trucks) from a distance of around 100 m. The microphone will be placed in an open area on land, and the goal is to identify when a vehicle is approaching.

Currently, I am evaluating microphones like AOM-5024L-HD-R and CMA-4544PF-W, connected to a MAX9814 preamplifier module, with the output fed into an Arduino Uno ADC.

My questions are:

  1. What type of microphone is most suitable for long-distance vehicle detection (100 m)?
  2. How can I calculate whether the microphone output voltage will be sufficient for reliable detection at that distance?
  3. Should I use additional filters (e.g., low-pass or band-pass) to separate vehicle sound from background noise (wind, people, etc.)?
  4. Would I need a higher-gain preamplifier or a different approach (like a geophone or array microphone) for better detection?

Any advice, references, or design suggestions will be very helpful.

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  • 0

    Very intriguing project ! With no experience myself with the signal processing portion, Id like to learn more by asking questions that hopefully the community can help with.

    The microphone analog input of the sound source to Arduino has 2 properties: frequency bandwidth and amplitude. The amplitude for the Arduino input is 0-5v for 1023 counts. Your microphone detection of traffic at 100m is likely alot smaller amplitude than at 1m. Does the dynamic range of the signal provide digital resolution in Arduino , i.e. 50mV is 1 count ? 

    Traffic noise is likely low frequency- maybe as low as 30-50Hz, maybe to 500 Hz ? Analog filter would be good to get rid of unnecessary audio content.

    Do you envision to scan the analog input as fast as possible, or interrupt to create sampling comparable to 1 or 2 kHz ? 

    I could be making this task way overcomplicated, do you have some example code or library to convert the digital samples to a frequency spectrum ? I expect this library would be significant.

    I have played with a MSGEQ IC that uses a comparator ladder and filters to output bits based on frequency. 

    https://www.digikey.com/htmldatasheets/production/2071107/0/0/1/msgeq7.html?gclsrc=aw.ds&gad_source=1&gad_campaignid=120565755&gclid=Cj0KCQjw_rPGBhCbARIsABjq9cdKCctZg2WHu3NC_ZxKhzYaMPR5LzzfQyZzkXQYnzaytEZl5qho1fMaAieCEALw_wcB

    The Arduino code needed to scan & demultiplex is straightforward,  but you likely could not tell the difference between a truck at 100m or a duck at 1 m , without some knowledge of the frequency spectrum signature of the source. 

    Id like to understand more of the digital signal processing part, but particular to your project, maybe it better to focus on ground vibration for vehicle detection rather than audio. 

Reply
  • 0

    Very intriguing project ! With no experience myself with the signal processing portion, Id like to learn more by asking questions that hopefully the community can help with.

    The microphone analog input of the sound source to Arduino has 2 properties: frequency bandwidth and amplitude. The amplitude for the Arduino input is 0-5v for 1023 counts. Your microphone detection of traffic at 100m is likely alot smaller amplitude than at 1m. Does the dynamic range of the signal provide digital resolution in Arduino , i.e. 50mV is 1 count ? 

    Traffic noise is likely low frequency- maybe as low as 30-50Hz, maybe to 500 Hz ? Analog filter would be good to get rid of unnecessary audio content.

    Do you envision to scan the analog input as fast as possible, or interrupt to create sampling comparable to 1 or 2 kHz ? 

    I could be making this task way overcomplicated, do you have some example code or library to convert the digital samples to a frequency spectrum ? I expect this library would be significant.

    I have played with a MSGEQ IC that uses a comparator ladder and filters to output bits based on frequency. 

    https://www.digikey.com/htmldatasheets/production/2071107/0/0/1/msgeq7.html?gclsrc=aw.ds&gad_source=1&gad_campaignid=120565755&gclid=Cj0KCQjw_rPGBhCbARIsABjq9cdKCctZg2WHu3NC_ZxKhzYaMPR5LzzfQyZzkXQYnzaytEZl5qho1fMaAieCEALw_wcB

    The Arduino code needed to scan & demultiplex is straightforward,  but you likely could not tell the difference between a truck at 100m or a duck at 1 m , without some knowledge of the frequency spectrum signature of the source. 

    Id like to understand more of the digital signal processing part, but particular to your project, maybe it better to focus on ground vibration for vehicle detection rather than audio. 

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