haw i calculate velocity if my sensor give me a voltage?

[edi_sn]

haw i calculate velocity if my sensor give me a voltage?

[NIquist]

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@edi_sn wrote:

haw i calculate velocity if my sensor give me a voltage?

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You MUST realize that nobody can answer that unless you tell us what kind of sensor right??? 

If you want help here, be specific with your questions.

[GerdW]

Hi edi,

you need to read the datasheet of your sensor to know the conversion parameters from voltage to speed.

Then you just apply those conversion parameters to your voltage measurement!

Generic answer to a generic question…

[camerond]

The next time your sensor gives you a voltage, have a friend measure how high you jump with a ruler, and how long it takes you to come down with a stopwatch. Your average velocity then is twice the height you jump divided by the time you were in the air. Couldn't resist.

Cameron

[edi_sn]

my sensor is a accelerometer.

i have to determine the velocity of a motor by using this sensor. I masseur with this sensor the vibrations of my motor, and i have to find a relation between  the signal of sensor and velocity

Model: 603C11

General purpose, industrial, ceramic shear ICP® accelerometer, 100 mV/g, 0.5 to 10k Hz, top exit, 10-ft integral cable, single point ISO 17025 accredited calibration

Sensitivity: (±10%) 100 mV/g (10.2 mV/(m/s²)) Frequency Range: (±3dB) 30 to 600000 cpm (0.5 to 10000 Hz) Measurement Range: ±50 g (±490 m/s²) Electrical Connector: Molded Integral Cable

[crossrulz]

V = V0 + a*dt.  So first you convert the voltage into acceleration.  You can then just add the previous velocity with the current acceleration multiplied by the sample rate.  Or you could just integrate.

[edi_sn]

haw i convert voltage in acceleration?

[GerdW]

Hi edi,

did you read your own sensor datasheet?

This says it all: Sensitivity: (±10%) 100 mV/g (10.2 mV/(m/s²))

[pjr1121]

Since you can't assume your acceleration will be constant (the motor has to reach a final speed eventually), integration is what you need to do.  Measure the acceleration as a function of time and integrate the data.

This sounds like an extremely unusual way to measure a motor speed.  What if the acceleration/deceleration is below your measurable threshold?  Can you measure the rotation speed directly?

Even without information of the signal/velocity conversion, you can create this data by recording the sensor output for a wide range of known velocities.  Then simply use this data as a calibration file.

[edi_sn]

thanks!!