I am dabbling with a MKR nb 1500 and need to read a pressure transducer. Most transducers come in 5vdc, 12vdc, or 24vdc (4-20ma). But all of the analog input pins on the MKR are 3.3v. Rather than adding more electronics to step down the voltage, I am considering using an oversized 5vdc transducer. So if the max I plan to read is 100psi, then I will use a 150psi transducer. All of the math should still work for the 5v transducers, since it is still returning between .5 and 4.5 volts, but it should never return over about 3vdc.
I think the caution is if there is a risk that it ever returns the full voltage of 5v. It could blow the MKR. I think that risk is small enough that I will keep it simple and used the oversized transducer.
5volt sensors with ratiometric output shouldn't be used with 3.3volt-logic boards.
Their output not only depends on pressure, but also on supply voltage.
You will have instability if you try to make it work on a 3.3volt processor.
Leo..
What about using a simple voltage divider to reduce the sensor output down to a suitable range, plus an identical (as far as possible) voltage divider to reduce the 5V down and use a second analog input to measure that. Then some maths to recalculate the ratio?
Industrial sensors usually have a 4-20mA current output, so the signal won't degrade over distance.
They are commonly powered with 24volt, but 8-16volt (12volt) is also used.
They are used with a current-to-voltage converter (a resistor and some protection parts),
and that (low) voltage can be read with a 3.3volt or 5volt MCU.