Let's Make Robots!

Can't get sound detecting circuit to work with picaxe 28x1

Greetings from Finland

I am trying to build this sound detecting circuit from picaxes homepage to use with a picaxe 28x1. ( http://www.rev-ed.co.uk/docs/picaxe_sound.pdf )

 

 

 

 

 

 

 

 

 

 

I have breadborded the circuit and double checked every connection. The problem is that it won't react to sound in any way. I wrote this code:

main:
readadc 1, b1
debug
goto main

The reading (b1) I get from the debug window is changing when I turn the pots but it does not react to sound. I have swapped out all the transistors and the pots and tried another microphone without any difference.

I am not sure that I understand how the adjustment on this circuit works, but I have bean playing around with the pots a lot and at no point have I got this circuit to react to sound.

My setup:

 

Any help is highly appreciated!

 

***EDIT***

I breadborded the whole circuit from the beginning and the same problem. It is got to be something simple that I don't understand. This is driving me crazy! The only components I could have placed the wrong way is the microphone, diode and the transistors, but according to the datasheets they should be alright. hmm...

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

I got it working!!! :) Now I can sleep again! I still don't know what the problem was. I tested all components and they all was working. The eight time I breadboarded it it just started to work. One possible explanation could be that I have some junk in my breadboard that made a short.

Also this circuit is holding the output high for a few seconds every time there is a sound. This was not a good thing for my purpose so I changed the holding capacitor (c4) to a smaller value (104nF).

Administrators feel free to delete this post if you don't think this post will benefit any readers.

Problem solved.