You are correct but I have all the support chips too (came in the same bundle) and got them cheap.

I would LOVE to use one of the newer options however with needing to build 90 of them I guess you can see why I am using what I have on hand. Our rescue facility cannot afford to spend the money since it is only funded by us personally...
We are trying to set things up where we can SAFELY leave for a day or two when needed without compromizing the animals or trusting that someone else would do all that is needed...

I appriciate all the help! So far a lot of the ideas while great have already been explored by me and ruled out due to lack of $$$.

Now if someone had the newer chip solutions and wanted to DONATE them I would be happy to implement them in the system.

Once the design is completed I plan to make it freely available to anyone that wants to build it...

I will re-design the finished controller for the newer solution for a single unit to test so the esign is as bug free when posted as it can be...