I am OK at embedded programming, but I couldn't figure out the root cause of what I was seeing. I looked through the core ESP8266 Arduino code, and I couldn't see anything wrong with the interrupt handler. So... very curious if it's my hardware, or some other weird little so...
USB Power bank for the NodeMCU version, or a voltage buck/boost + AAA batteries + 1000uF capacitor for the ESP-01). Electronic dupont cables, or UTP/Phone cables, long enough to connect the microcontroller to the sensor. Arduino programming environment (PC or Mac, Arduino IDE, data micro ...
The library is included in the official Arduino library manger and the optimum way to install it is using the library manager which can be opened by themanage librariesoption in the Arduino IDE. Search "fourteen" in search bar of library manager to find it quickly. ...
Initially I didn't add any tension spring to altitude axis encoder; it seemed its weight itself is enough to keep it in positive engagement with the gear. But while testing I was getting an inconsistency of up to 20 counts when I moved the telescope from vertical position to horizontal...