Measuring Displacement using LVDT with NI USB-6002

[lruiz123]

Hey! I was wondering if it is possible to get displacement from an LVDT sensor using the USB-6002 DAQ. Labview shows that there is no supported device for LVDT input so I was wondering if there's any way I could measure the displacement using this DAQ. Thanks!

[Henrik_Volkers]

why not using the soundcard?

a LVDT needs a sine input -> Sound out

you need a phase correlated input -> two inputs are there: one as ref (voltage divider) from the sound output, one for the LVDT

sound vis and tone detection and your done 🙂

Edit: missed the calibration 😄

[lruiz123]

Would I be using the sound card in my computer or would I have to purchase another one? Also, does it have to be an internal or external sound card or does that not matter? Thanks for the reply by the way 🙂

[Henrik_Volkers]

What type  LVDT do you have?

What soundcard connectors do you have on your computer?

Any soundcard with a headphone out and a stereo input will do it. The external migth be worth some money if you are afraid to blast your build in 😄

Depends of the use case of your LVDT (near a TESLA-Coil?? )

You can use the build in soundcard,usually two old headphone cables (for the connectors)  some resistors for voltage dividers and maybe capacitors ( and I suggest 8 diodes to protect your mic or line in input ) are needed.

And you will need a caliper, micrometer or other artifacts like gauge blocks to do a calibration.

You use the headphone out to send a constant sine to your LDVT , maybe add a 16Ohm resistor in series for protection, one lineIn or mic channel to read the differential voltage and the other lineIn/mic channel to read the sine exitation. Additional resistive voltage dividers will be needed to match the signals to the input. The amplitude ratio and the phase of the inputs are a measure of the distance. The connections depend on the type of LDVT and your soundcard.

AD has a IC to drive and read a LVDT...AD589 or AD689

TI including a 24bit ADC ....PGA970