Can I build EnvisaLink or something like this?

I am looking at EnvisaLink version 4 and the price is about $100.

I want to know if there is a way to build it cheaper, for example with NodeMCU or something like this. The idea is that I have existing ADT security system. I connected sensors on my doors and windows, but I want to have ability to arm/disarm my house remotely.

Anyone know if I can do it or should I buy it?