I decided to change the supplied titan extruder on my Anycubic Chiron to a dual geared extruder.  After researching a number of third party designs I bought a relatively cheap but seemingly well made option on Aliexpress.  To make this extruder work with the Chiron I had to design a new filament sensor assembly.  The extruder does not require any modification to the firmware or wiring.  So I designed a filament sensor housing and I added a pneumatic connector to the end of the housing so I can use bowden tube to act as filament guide.

I found the pneumatic connector on Aliexpress - https://www.aliexpress.com/ite...

The dual geared extruder also came from Aliexpress (for Chiron a left type is required) - https://www.aliexpress.com/ite...

I designed the housing for the filament sensor in three parts to facilitate printing and adjustment. If you want to change the position of the filament sensor you only have to modify the mounting bracket.

The changeover was quick with no issues and I had the printer going again within 4 hours starting the printing.  

As for the new dual gear extruder - works flawlessly!!