New home of the old techref: http://techref.massmind.org/techref/index.htm which is no more. Content will be added back here slowly over time.
For now, see:
The Hybrid Disk Encoder project
Arduino Dynamixel / Stepper / IO Controller
The SDMG-Web-Bot
An ESP based "battle" robot controller that uses your Cellphone webbrowers
NOT
an app.