Re: NodeMCU ADC (A0) correct operation
Posted:
Sun Oct 29, 2017 11:09 amby QuickFix
songa wrote:thank you very much guys and sorry for the misunderstanding 
Hehehe, yeah sometimes things can be confusing.
Here's a picture that will describe the separate elements (and their names):
Schematics and other info of
the NodeMCU can be found here.
Re: NodeMCU ADC (A0) correct operation
Posted:
Mon Oct 30, 2017 6:22 pmby songa
QuickFix wrote:Here's a picture that will describe the separate elements (and their names),
Schematics and other info of the NodeMCU can be found here.
Thank you QuickFix, I took a look at the link and saved some more information.
Re: NodeMCU ADC (A0) correct operation
Posted:
Thu Apr 04, 2019 8:14 amby JHEL
Hi i figured out the problem.
the esp82xx connects at time of mesurement the vcc an voltagedivider at a0 . 10k up to internal reference and 10 k down ti gnd. so it works with an esp12x or esp8266 fine and perfect.
in case of use an nodemcu is " extern " an 100k pulldown connectet !
bacause that you get 2.9 volt istaed the in my case correct 3.25 volt
Its an right and legitim to korrect the value depends on the external part are connectet.
At nodemcu you can easely the mesured value by 0,9
example:
float vcc = ESP.getVcc() / 900.0; //normaly 1000.0 - nodemcu has a pulldown 100k at adc0 therefor 900 !!
lcd_left.setCursor(0,3);
lcd_left.print(vcc);
regards from jens