I know I haven't put up any updates in a while so I thought I'd at least put up an update saying I'm still working on this project. I've been devoting most of my time to getting the RPi working with the Arduino to communicate and read the ADC. This has proven to be a bit more of an undertaking than I initially thought, but it has been good learning experience. Once I have code working I'll post the followup with code and details.

The ADC I settled on is based on the HX711 and can be found on Amazon (http://smile.amazon.com/SMAKN%C2%AE-Weighing-Dual-channel-Conversion-Shieding/dp/B00M6POINC/) for ~$7USD. It can handle two analog channels and will work well for the trash to recycle bin differential. Granted at the larger end I'd like to add another one of these to allow for different types of recyclables to be measured (Glass, Plastic, Paper) but for now I'm working with just one.

As for load sensors, I'm playing with several different ones I got in different bathroom scales. Most are the typical 3 wire variety and look very similar. I've also ordered a set of 4 wire ones from Amazon (http://smile.amazon.com/Electronic-Weighting-Sensor-pressure-transducer/dp/B00VV4RN3Q) as well due to their low cost and the fact I want to see how different they are. The only concern I have is they are 2 hole setups and I have no clue where the deflection point is, but that should be part of the fun :)

Anyways, more details as I make progress.