Next in her interesting series about Arduino and audio input/output, Amanda Ghassaei has continued with a study on how to detect the frequency of the signal being measured by an Arduino's analogue input pin. After reading through it, her work is very good. Amanda discusses detecting positive and negative slopes of the incoming signal, peak detection and more - and implements these in the sample Arduino sketches. Furthermore Amanda moves on with sine wave and pitch detection with more examples. All very interesting and worth a good read.
For a simple source of audio to sample, start with a simple electret microphone board - and our Freetronics MIC: microphone and sound module is perfect.
The MIC: contains an integrated dual signal amplifier converts the sound to separate channels for pulse / frequency measurement, and sound volume (pressure) level. Designed to connect straight to an Arduino compatible microcontroller, Analog to Digital converter, or many other circuits. For more information and to order click here.