I have been testing my very dumb arduino code for esp8266 written for dual input filament detector (it knows when filament ends on "spool" or when You want change filament). I'm running smoothiware so any changes in the firmware code made by me would never be merged (smoothie owner don't want to code any additional features and my skills are not with a quality they demand). That's why i'm using esp8266 connected to smoothie by serial and sending console commands / g-codes to control additional features like:

- pause on filament run-out

- sensing filament in extruder for semi-auto filament loading 

- automatic heating up when detected that new spool is loaded

- sending the user instructions when filament changing or run-out that can be read on 3d printers LCD panel

A this point like i said at beginning the code is very stupid because it only sends commands but doesn't wait to receive any "ok" from the printer... And that's what i want to code next (will be glad if anyone want to help - code is on github inside protoDEV_coreXY project). 

The second filament run-out detector installed on the system is a new one. It's my latest design with hall-e sensor, very small bearing and neo-magnet.