Hello! I am looking for a Linear Variable Differential Transformer (LVDT) that would be suitable for use with an Arduino Uno or Nano. I want to be able to read the analog signal from the sensor and display it on a typical lcd screen. The only obstacle I found was choosing an LVDT, a search on Digi-Key gave me 16 choices that were in stock and had datasheets. I think the this is the one i'm looking for, but it costs around $250 USD!!! Are there any other options?
The output from the LVDTs that I know of is AC. Not readable with an Arduino without external electronics.
An LVDT is 3 coils. You feed two in antiphase and measure the signal on the sense coil. This can be done
with sinewave or squarewave (which is more amenable to using an ADC easily).
The datasheet is the place to determine which excitation mode (and amplitude) is most suitable for a particular device.
The core material will determine the frequency and whether squarewave drive is going to work well.
For sinewave use you'd need to both generate an analog sinewave and measure the sense coil
amplitude and phase, which is more complex.
These days people just use linear encoders.
You don't mention a stroke? If you want a lower cost and you have a short stroke (<6.0") consider a linear position sensor pot from any of several manufacturers like Bourns, BEI or others. A Google of "linear potentiometer position sensor" should get you a few dozen hits. With better uncertainty goes a higher price but they come in at a lower cost that a transformer type LVDT and for use with an Arduino require no extra parts.
Ron
I know this is an old-ish thread but I've been asking a similar question and came across this helpful youtube vid..... I can't comment on whether the theory works or not but I'd be willing to try if I can get my hands on a cheap LVDT sensor..
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