Hi I have a wemos D1, the rated max input on A0 is 3.3V I'd like it to input up to 5V, so I can monitor the battery the unit is connect to, which should be from 3.1V to 4.2V typically. How can I step the voltage down enough to read it, 1/2 would be ideal as thats easy to fix in software as well. a voltage divider seems like the way to go, but what would be the resistor values for the smallest current draw possible to conserve power.
A Wemos D1 mini already has a 220k:100k divider on the analogue input.
To measure up to 4.2volt, you just use a 100k resistor between battery and analogue pin.
To measure to 5volt, use 180k.
Leo..
Hello,
have you check this page? for Wemos D1
[u]http://cyaninfinite.com/tutorials/getting-started-with-the-wemos-d1-esp8266-wifi-board/[/u]