Paul,

I have been experimenting with signal condition for the 2nd gen CAS
sensor.

Do you know how much voltage it produces?

It seems to be producing a AC signal at .05 volts at 500 rpm CAS
shaft speed.

I am trying to increase the voltage with the LM1815 chip but can’t
get it to work.

Does the voltage go up when you turn it faster?

Does the CAS turn 2 X Eshaft speed?

Thanks for any help.

Joe Berki


Yes it does. That LM1815 handles that very well.

You must however use a 5 volt regulator LM78L05 to power the LM1814
chip. It is designed to output a 5 volt 100 usec wide pulse to a
computer.


The second gen CAS turns at half E-shaft speed. That is why there are
two tits on the top part of the rotor shaft. That way you get one
signal pulse per revolution of the e-shaft at 22 degrees BTDC rotor
1.

You will need two LM1815's. One for the upper level and one for the
lower level if you need that.

If you are using it for something other than a computer and you need
a higher voltage a good chip to take in 5 volts and put out 12 is a
ULN2003. It will work up to 30 volts. It is easy to use and will
tolerate a lot of abuse. You get six Open Collector outputs.


Paul Lamar

Paul,

I found the problem it was a bad scope probe.

I hooked a piece of coax to the circuit from the scope input  and it is giving me 5volt pulse as advertised.

I have a LM2917 frequency to voltage converter that I will connect to the output and see what kind of voltage I can get as rpm goes up and down.

I can feed that to the arduino for tach circuit.

Joe Berki

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