I need to reduce the voltage from 12V to 3.3V for a nodeMCU digital pin input.
I want to minimise the current draw of the voltage divider by using high value resistors.
Is there a problem if I go too high? The digital input might need to draw a little current?
Any idea what current I should allow?
Am I right in thinking that the resistor inbetween the 12V source and the 3.3V pin is the one that will determine the current by ohms law?
There will also be the internal resistance of the input to consider I suppose.
Or....... is there a better way of reading a 12V source (in a digital fashion). Maybe a transistor between 3.3V and the input pin triggered by the 12V source?
Thanks in advance for any help!