OpAmp Non-inverting Amplifier not inverting

[johnerrington]

Using Operational Amplifiers in your Arduino project

Introduction: Using Op Amps to measure signals with an Arduino Who is this tutorial for? Well, not "newbies" or anyone happy to just connect together modules. If you have a LITTLE knowledge of electronics, have perhaps used a transistor or a FET to extend the output capability of an arduino, and want to learn about ways to handle different Analog inputs, than read on! What will you need? All you will need to carry out a few simple experiments is a breadboard, a couple of (very inexpensive) …

The op amp you are using is not rail-rail so you would need a negative supply.

Be aware some "chinese" op amps are suspect.

This page may help

skillbank: Experiments and projects with an Arduino microcontroller

The normal analogwrite uses a low frequency - under 1kHz - so isnt easy to filter. So you can use one of the timers as shown in that page to work the pwm at a higher frequency.