I'm trying to use the ADS1115 with the ESP32 to measure voltages. It is very accurate when connected to a source voltage but fluctuates in the 0.5V ot 0.6V range when nothing is connected. Some searching indicates that I may need to use a voltage divider with the input pin connected to the midpoint so it is not floating. This is a problem as I will not be able to read voltages below the midpoint of the voltage divider using the single end method. The Arduino ADC doesn't have this issue. Is there a way to fix this.
All CMOS inputs float if not connected, this is normal. Why is it be a problem that a floating input is reading random? I can't figure out what you mean by this:
This is a problem as I will not be able to read voltages below the midpoint of the voltage divider using the single end method
Please describe the problem that you are actually trying to solve.
What voltage do you want to measure, from what circuit?
When writing this reply, I realized that once the sensor board is connected to the power supply board it will have a connected ground. Testing the sensor board (with the esp32 and ADS1115) by itself causes the problem. So I guess there is no problem once connected. Thanks for helping me think this through.