Hello,
I would like to read a sensor data using voltage divider; however, I dont want to use a resistance in series with the sensor. I am aware that I can use PULLUP/DOWN resistors instead of this additional resistor. I tried that on an Arduino Mega board and it worked perfectly uisng the below line of code:
pinMode(A2, INPUT_PULLUP);
However, I was not successful when wanted to do the same using an Adafruit ESP32 board. Any clue?
Thanks
No, internal pull-ups are not anyhow precise. Otherwise try pulldown
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A pull-up or pull-down resistor is not the same as a series resistor.
What is the output voltage of this sensor?
Is it analog or digital?
Which ESP32 feather, there are several different versions?
It is a strain sensor, connected to GND on one side and to A2 on another side. It is analog. I am using Adafruit ESP32 Feather Huzzah.
The Huzzah has only one analog input A0, you can't use a pullup on the pin
The input voltage must be limited to 1.0V so you will need to use a voltage divider.
Thank you. But, I am a bit skeptical about your saying that the Huzzah has only one analog input. Because I used the same board for 5 analog inputs and it worked properly. It is also mentioned in the specs.
Adafruit_Huzzah32-esp32_eng_tds.pdf (2.0 MB)
My only problem is that I can not use the pullup resistors as voltage dividers.
You are are correct, I was looking at the Huzzah feather ESP8266 but I have to check if pullups are allowed on analog pins of the ESP32
Well I know this for sure A2, A3 and A4 do not have pullup/pulldown. So try one of the other channels
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