I got a flowmeter that is operating at 5v (basically an enclosed hall effect sensor and magnet). It needs a pullup resistor of between 1.6k - 2.2k between sig and vcc. ( https://www.conrad.com/p/bio-tech-ek-fch-m-pom-lc-g-18-flow-meter-fch-m-pom-lc-001-35-lmin-150391 )
Now, knowing that connecting a 5v device to the pis gpio that are using 3.3v, i would probably kill the pi.
I know you can put some resistors to step down the voltage to 3.3v, but I have no clue of how what resistors to use and how to connect them.
Could someone please help me telling me what resistors to use and how to connect them?