SparkFun Forums

[ajk265]

I am working with a pretty simple circuit and riding the struggle bus. I have the Electret Microphone Breakout (https://www.sparkfun.com/products/12758) and I am trying to get it to play out of the Thin Speaker (https://www.sparkfun.com/products/10722). All I am hearing is a periodic click out of the speaker.

First, here is my setup (sorry for the ASCII art):

Code: Select all

                            +5V
                             ^
                             |
                        -----------
                        | Speaker |
   +5V                  -----------
    ^                        |
    |                        v
 -------                 ----------
 | Mic |---> 250 Ohm --> | 2N3904 |
 -------                 ----------
    |                        |
    v                        v
   GND                      GND

I hooked a quick ADC -> 8-bit digital output from the microphone breakout board, and verified with a logic analyzer that it is getting full precision (0 to 5V) out of the microphone when there are loud noises. Originally I put it through an additional inverting op amp, but this looks unnecessary.

I also verified that the NPN transistor collector is connected to the negative side of the speaker and the emitter connected to ground. From looking around online, this looked like a way to drive the speaker since the op amp on the breakout cannot supply the full quarter watt.

I'm pretty sure there is a glaring error is what I am doing, but I cannot see it. I'm just trying to start with the sound from the microphone playing out of the speaker.

Any help would be much appreciated. Thank you!

[ajk265]

For reference for anyone else that has this problem, I replaced the speaker with a 10k resistor and then put the speaker from the collector through a 1uF electrolytic capacitor. The sound is pretty poor quality, but it does play.

Note: I looked for a way to delete the post since I solved the problem, but cannot find a button to do that.

[theropod]

Your solution might help someone else so don't think it needs to go away.

RS