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LilyGO / TTGO-LORA32

ESP32-TTGO-T3
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Battery Monitoring with BaT_test_ssd1306 #21

Open fabioetec opened 5 years ago

fabioetec commented 5 years ago

Hi,

I tried the BaT_test_ssd1306 sketch but I can't get it to work. The value visualized on display is always 0.0000 !!! Is pin 35 a non-exposed ADC pin where I can read voltage or should I connect something to that pin?

Thank you Fabio

DemitasseNZ commented 4 years ago

You need to add a voltage divider to send half of the battery voltage to the ADC on GPIO 35. I connected a 24K resistor between GPIO 35 & ground and another 24K resistor between GPIO 35 and the battery positive terminal. Now I get a good voltage reading. You need two resistors of the same value and around 10K, the exact value is not so important I am just short of resistors & have two 24K metal film resistors.

Shaedo commented 1 year ago

If this is correct, why is do they state "Add battery voltage detection Pin IO35" with the revision 5 years ago, and what's the point of the voltage dividers in the schematic? Adding a voltage divider would allow you to measure on any ADC, so what's special about GPIO 35? (I might be missing something obvious here.... ) (I appreciate this is a nero-ing the post, but it's still valid)