Need Help with a project ?

[Gar1]

Hello,

I need help with a project I have to do.....

The Aim of the project is to construct a system that allows the control of a cooling fan through the parrallel port of a Pc. This is to include a microphone to provide feedback about the true speed of the fan.

I would very grateful for anybodys ideas who could help in the circuit design.

 

[Sebi]

Why a microphone? Apply a small magnet and a cheap hall-sensor or reed-tube for rotation sensing.

 

[bogdanfirst]

well you could use the 8 output bits to control the speed but that means that you would have 255 speedes...lol, i dont think you need so many. maibe use onlly 4 bits. to get 31 speeds...i think it is enough.
but for the speed i suggest use a special sensot that either provides a voltege for a specific turation(a frequency to voltage convertor) or use a circuit that you should build

 

[kinjalgp]

4-Bits for 31 Speeds ???? :?:
2^4 = 16 = 16 Speeds

 

[bogdanfirst]

ya , i dont know where my mind was when i wrote that .....
acutually 15 speeds if you dont consider the state when it is off.
sorry about the confuzion garl....

 

[herbymcduff]

could just use three (only 7 speeds, 8 including 0)
or use just two (only 3 speeds, 4 including 0)

Or am I just way off the line?

 

[bogdanfirst]

well you are not of line....
but first the guy that needs the project should tell us what he needs.