I believe I found a way to use just an ESP8266 module to control the stepper drivers directly. This post explains how. Background: 1. Other projects show how to use ESP01 as a wifi-serial bridge to the arduinos, but serial is still a bottleneck and wifi uploads are impractical. 2. Altough ESP8266 does 160MHz at 32bits processing (versus 16MHZ 8-bit from most Arduinos) it has insufficient realby lhartmann - Developers