[Shotimes] BARO sensor

[MonsieurBoo@aol.com]

> Anyway at sea level you should be seeing around 160-170 Hz.  As
> you apply vacuum to the open port the frequency should decrease to  a
> low of somewhere around 90Hz. The sensor has 3 wires. One is the 5  VDC
> supply, one is a ground and the middle pin on the sensor should be  the 
changing
> output. I do have instructions for using a tachometer to  read the 
frequency.
> Set it on 4 cylinder setting and you should see 4800  rpm with no vacuum and
> the rpm's should decrease with increasing  vacuum.
 
Hmmm, with a 5V level, any electronic musicians out there could hook the  
output to an op amp and drive a speaker with it.*  Then compare  it against some 
instrument you have handy.
 
For example a keyboard.  150 Hz is roughly a D3 (D below middle  C) and 90 Hz 
is roughly an F2 (2 Fs below middle C).
 
Or a guitar:  150 Hx is roughly the same as the open D (4th)  string.  90 Hz 
is about the same as the low E (6th) string on the second  fret, which takes 
it up to an F2.
 
If you don't have any suitable instruments, here's a link to a set of  guitar 
tuning tones but you would have to use the open low E and it will be one  
tone lower than the BARO sensor with vacuum applied:
 
_http://www.guitartips.addr.com/tuner.html_ 
(http://www.guitartips.addr.com/tuner.html) 
 
These are moderately low frequencies so don't use too dinky a speaker  ;-)
 
Cheers
Mark LaBarre
94 atx 130k
 
 
*Or you could drop it down to max 1V and run it into a  line-level input to 
your stereo, using appropriately-valued bridged resistors as  at:  
_http://www.termpro.com/articles/faders.html_ 
(http://www.termpro.com/articles/faders.html)