Filament Sensor for the Ender 3

After installing the BL-Touch on the Ender 3, I realized that the stock Z-stop switch is not of much use anymore. So I thought of unscrewing it from the Ender and making it into a filament sensor.
I connected it to the Raspberry PI, and use the "Octoprint Enclosure" plugin to detect when the filament runs out. Works pretty well.
After printing the case for the sensor, insert two small pieces of PTFE tube like shown in the pictures, to avoid the filament to scratch against the PLA.

Please post your makes or let me know suggestions in the comments. Or if you come up with a better design please refer the remix.

If you found this useful, please donate what you think it is worth to my https://paypal.me/umbacos to help cover the time of design.
Thanks, Enjoy!