ArturA98
Posts: 5
Joined: Thu Sep 22, 2016 11:10 pm

ADS1115 problem

Sat Dec 10, 2016 12:05 am

Hey everyone!

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!

Thanks,
Artur

Bruce_Pi
Posts: 20
Joined: Tue Feb 21, 2017 5:09 pm

Re: ADS1115 problem

Thu Feb 23, 2017 4:16 pm

when nothing is connected to the ADC it will give your random values due to noise.
so if you want to use it in a differential way make sure you have the input connected on both channels.
ADS1115 have lot of parameters which you need to set before you can use if properly( like gain, resolution, differential or single-ended)
If you are looking for a python lib you can find over here.
https://github.com/ControlEverythingCom ... er/ADS1115
thanks

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