First of all, I'm not very good with electronics, I know the basics, but I'm hoping to learn more during this project!
I'm currently working on a project where I need to measure a low voltage(about 2-3 volts), and to write it to a text file. I'm planning to use an ADS1115 Analog to Digital converter for this. I've connected ADS1115s VDD to Pis 3.3V port. Same with ground, SCL, SDA. I've downloaded the Adafruit libraries for the ADS1x15, and it seem to work fine. I'm trying to use the differential mode to measure difference between A0, and A1. If nothing is connected to the ADS1115, the reading is 0, which I guess is right? However, as soon as I connect a single wire to A0 or A1(not plugged in on the other end) the readings get really weird. They jump between just about any number randomly. I thought it could be electromagnetic fields, but the readings are way too wrong. For testing purposes, let's pretend I'm trying to read the voltage on a normal 1.5V battery. Also, I'm on the Pi Model B+ if that matters.
I'd appreciate a lot if someone could point me in the right direction!