Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 7 of 7

Thread: Teensy 4.0 Sound from Electret Bob to FFT

  1. #1
    Junior Member
    Join Date
    Feb 2020
    Posts
    4

    Teensy 4.0 Sound from Electret Bob to FFT

    Hello! I just purchased the 4.0 and I was looking to do some FFT on live audio. I currently have a microphone that produces a 1.25V biased 2V peak to peak signal which I have been using with a MSGEQ7 and Teensy 2.0++. I would like to cut out the temperamental middleman and do it in software.

    I understand that the ADC is still being worked on, but I wanted to ask if there are any alternatives for a mic BOB or if I would be best just waiting until an ADC appears? Thanks for any help you can provide!

  2. #2
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    6,155
    I'd use the Audio Shield.

  3. #3
    Junior Member
    Join Date
    Feb 2020
    Posts
    4
    A good suggestion, I'm hoping to avoid additional hardware, so waiting looks like the best option for the time being. Thanks for your help.

  4. #4
    Senior Member DD4WH's Avatar
    Join Date
    Oct 2015
    Location
    Central Europe
    Posts
    526
    Another option would be to use an I2S microphone breakout board.

    The ICS43434 delivers excellent audio results if you care about a little filtering of the 3.3V supply.

    https://www.tindie.com/products/oneh...al-microphone/

    https://forum.pjrc.com/threads/52175...l=1#post183337

  5. #5
    Junior Member
    Join Date
    Feb 2020
    Posts
    4
    That looks like a great option. I don't need it to be a particularly clean signal, but it still seems like it does what I need. Thanks for your help!

  6. #6
    Member
    Join Date
    Aug 2016
    Location
    Australia
    Posts
    63
    An additional option is to use MEMS microphones which often communicate directly via I2S or SPI.

    There's a good description in this document https://www.st.com/content/ccc/resou...DM00187403.pdf about the options.

    This thread looks at some of the practicalities of MEMS for Teensys. https://forum.pjrc.com/threads/57697...light=mems+i2s

    And this one looks at using multiple MEMS microphones https://forum.pjrc.com/threads/58937...light=mems+spi

    Have fun!

  7. #7
    Junior Member
    Join Date
    Feb 2020
    Posts
    4
    More great information! Thank you. I thought i2s was a higher level system, but it looks like little i2s BOBs may be just as good as the analog one I have.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •