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  • Author Author: tariq.ahmad
  • Date Created: Date Created
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Making a WiFi Connected Audio Spectrum Analyzer with ESP32 -- Episode 570

This IoT/Web based Spectrum Analyzer uses a single ESP32 to create up to 64 channels to visualize the different audio bands.It uses only 6 external components to function .It has no LEDS or TFT screens but it uses a HTML webpage to display all the frequency bars. The ESP32 used is running on both processor cores. Core 1 is used to run the main loop of the program while core 0 is used to constantly update the webdata. Although the program itself makes it possible to run on a single core, using both cores will lead to better performance. This is so easy to build and program; you just have to try it! You won’t even have to install the ARDUINO software. Just use the web programmer to upload the precompiled binary file.

 

Supplemental Content:

Layout Schematic
image image

Bill of Material:

Product Name Manufacturer Quantity Buy Kit
Resistor Te Connectivity 4 Buy Now
Capacitor TDK 1 Buy Now
Switch Tactil Te Connectivity 1 Buy Now
 

Additional Parts:

ESP32 DOIT DEVKIT V1.0. You can use other ESP32 but you will have to adjust the wiring accordingly
A breadboard or experimantal PCB to build the circuit on.

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  • Great project!  A note for anyone using ESP-IDF stable(v4.4.2) - the adc_gpio_init() function is deprecated.  For this build, consider replacing:
    err = adc_gpio_init(ADC_UNIT_1, ADC_CHANNEL_0); //step 1
    with
    err = adc1_config_channel_atten(ADC1_CHANNEL_0, ADC_ATTEN_DB_0);   // step 1, ADC1, channel 0 -> pin36 (note: change attenuation value as needed)

  • in reply to r2dev

    Hi R2dev

    Thanks for this important hint....

    In my case the compiler continued with lots more verbose messages then eventually stalled with the verify icon locked in a "yellow" state. (I am using Arduino IDE V2.1.0.) I had to scroll back to find the offending error message and exit the Arduino IDE to continue working.

    The key part of the misleading error message is: 

        C:\Users\....\Arduino\Webspector-main\Webspector\I2SPLUGIN.h:52:9: error: 'adc_gpio_init' was not declared in this scope

    Now that the code compiles and uploads I can add the miscellaneous hardware - I am confident that it is working as probing around SVP pin with my fingers picked up enough noise to analyse. It would be interesting to display the raw time domain signal either simultaneously or as a selectable option. This would make a really cheap teaching tool.

    Does anyone know of a project using Arduino ESP32 scope with a web based display?

    Thanks DavidB

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  • in reply to r2dev

    Hi R2dev

    Thanks for this important hint....

    In my case the compiler continued with lots more verbose messages then eventually stalled with the verify icon locked in a "yellow" state. (I am using Arduino IDE V2.1.0.) I had to scroll back to find the offending error message and exit the Arduino IDE to continue working.

    The key part of the misleading error message is: 

        C:\Users\....\Arduino\Webspector-main\Webspector\I2SPLUGIN.h:52:9: error: 'adc_gpio_init' was not declared in this scope

    Now that the code compiles and uploads I can add the miscellaneous hardware - I am confident that it is working as probing around SVP pin with my fingers picked up enough noise to analyse. It would be interesting to display the raw time domain signal either simultaneously or as a selectable option. This would make a really cheap teaching tool.

    Does anyone know of a project using Arduino ESP32 scope with a web based display?

    Thanks DavidB

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