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Taking a sound frequency

Posted: Mon Nov 13, 2006 6:59 pm
by highj1
hello I have a small problem, i am designing a device which will test the refill time for a asthma medicine bottle. Firstly there is a loud out burst which is the initial sound of the medcine coming out, then there is a click as the diaphram inside refils, which then stops a second or so later (this is a constant sound). So basically i have to figure out a way to measure the time it takes from the main out burst to the inital refil and then how long the bottle takes to refil. These must then be used as outputs to control a circuit. (a stepper motor). So i need a way to measure these sounds (frequencys) and get them to control a circuit.

I decided that i would use a microphone find what frequency the sounds are at then using a vox type circuit or two, use them to turn on or off when this certain frequency is reached. however i have hit two problems; i am at the moment using audicity, and i am finding it hard to find out the frequencys at which these operations happen, so can any body help by recommending a better piece of software; and two my electronics has a little to be desired...:S so would anybody be able to give me a scheimantic or a circuit, or even a diagram which i can adapt.

Or is anybody had any ideas, which are better than this. i thought maybi using an equalizer i would be able to cut out the uneeded frequencys, but then i am finding it difficult to get these sounds to control a device on the computer, so any help will be brilliant.

Thanks

Jonnie (jonnie01@gmail.com)