1

Parts

  • Arduino Uno R3 (Atmega328 - assembled)
  • Adafruit Bicolor LED Square Pixel Matrix with I2C Backpack
  • Electret Microphone Amplifier - MAX4466 with Adjustable Gain
  • Half-size Breadboard
  • Breadboarding wires

Description
I have been following the build guide for the "Piccolo Music Visualizer" on the Adafruit website (https://learn.adafruit.com/piccolo?view=all), using all of the same components and code (following the guide exactly as shown). I first tested the 8x8 matrix to see if it was working properly, and it works beautifully. The problems started when I wired up the electret microphone...

In regard to how I wired this to the breadboard, I followed the example for the R3 on the Adafruit guide (since that's my current version):

Note
The files (code) used for this project are found here: (https://github.com/adafruit/piccolo). The ffft file is supposed to be saved to the library (this worked for me). The Piccolo file is supposed to be saved to the Sketchbook (this did not work for me - kept giving error messages when trying to reference it). I instead copied the code found in the Piccolo file, and saved it as a new sketchbook file. Let me know if this might be the cause of the problem. This is my first arduino project, so I am still trying to figure out how the IDE works.

Problem
The electret microphone is supposed to pick up audio and the LED matrix should display a waveform based on the loudness and frequency of the audio. Instead, I only have 2 bars on the bottom left lighting up (the effect is static - wont respond to volume or frequency changes). Oddly, when pulling out the microphone from the breadboard, the waveform begins displaying as it should, but in a glitchy/unstable form. I figured the problem was with the adjustable gain on the microphone, but no matter how much I adjust the screw only the 2 bars are affected and still static (when adjusted to the left only green LED, in middle is green and orange, to the right is red/orange/green on the matrix).

A little confused as to what the problem could be... is the microphone broken, code malfunctioning, wiring incorrect, etc.

Pictures to reference (DropBox link):
- See comment below for link (must have 10 rep to use more than 2 links in post)
(zip file contains 3 pictures: "wiring", "when_on", "pulling_out_mic")
Photos are over 2MB so I couldnt upload here.

  • Check your soldering on the microphone board header pins; sounds like a dry joint. – CharlieHanson Jan 3 '16 at 19:01
  • @CharlieHanson How would I fix a dry joint? I don't see any problems with the soldering, but I could be wrong. – ITSUUUUUH Jan 3 '16 at 20:30
  • Just add more solder; the more the merrier. The fact that the LED matrix seems to work 'better' when you're fiddling with the microphone board makes me think that the problem lies entirely with that little board. – CharlieHanson Jan 3 '16 at 20:32
  • @CharlieHanson You were right, it works perfectly now! Thanks so much! Post your comment as an answer and I'll accept it. – ITSUUUUUH Jan 3 '16 at 20:36
0

It sounds like a dry joint; the fact that the LED matrix seems to work 'better' when you're fiddling with the microphone board makes me think that the problem lies entirely with that little board.

Try adding more solder; the more the merrier.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.