I have been reading a book called Arduino Workshop, and just got to a point in the book where I thought I could create a project on my own with only using datasheets, but I am having issues. The type of project that I want to create is a simple clapper, you clap and it toggles an led. My problem lies with trying to get the microphone to read noise. I have attached a copy of the circuit using fritzing to this post. The electret microphone that I am using is Electret Microphone - COM-08635 - SparkFun Electronics(datasheet). To amplify the signal I am using a BD139 amplifier(datasheet).
I can get a reading from the microphone, however it only displays random values, and does not respond to any type of noise at all. I have also noticed that it slowly counts to 0 in the serial monitor when viewing its output, but I can never get it to go back up. Can someone please point me in the right direction, I was hoping this would be simple.