The idea for my project was to avoid problems when I have a spool tangle by having the out of filament cycle tripped when I have a spool tangle.
Here is how it works; I mounted a limit switch on each side of the spool cradle the rod that holds the spool holds the switches open when the rod moves up in the spool cradle and either one of the switches closes the change filament cycle will be activated. I also printed hubs for the spool with ball bearings and a mount to hold a clip to prevent the rod form rotating. "The cradle is also held down to the board that my printer is mounted on" (I removed the hold downs it works better without them). Most filament spools have the end sticking out near the hub glue the end to the spool and this will also work as a filament run out sensor. Or better yet set up a filament runout sensor and wire it in parallel with the tangle setup.
With the help of others there I found one pin available on the LCD (Pin4A or Pin 3) that is Pin 27 on the stock Anet a8 board using Marlin. I soldered wires directly to the pin 27 (pin3 -4A) and the 5 volt pin on the LCD (should have soldered the red to the 5 volt but it does not matter). Tried it to ground and using (false) did not work with help found I had to use the 5 volt and (true) in the firmware. I have uploaded a picture the back of my LCD.
As far as the firmware goes both the filament change and the out of filament must be active there is much information on how to do that available I won’t go into details.
I have uploaded a picture of the changes needed in the out of filament micro in the Marlin firmware. It is in configuration h. starting at about line 826 in Marlin 1.1.8. search for FILAMENT_RUNOUT_SENSOR.
I want to thank all of the people here that helped with my project and especially “truglodite”. I could have not done it without everyone’s help.
Please comment good or bad I am interested in reading your comments and seeing your makes.