I will be happy if you can help me modify code for my project.
My project goal is to output PPM (8 channels 22.5ms).
The inputs will be 4 Hall sensors (as Joystick) 2 switches (on/off)
And an external Head tracker which already output 2CH PPM (CH5/6)
Is it possible to modify this code to receive 2 external ppm channels + the analog source
and output all as PPM without the NRF24 transmitter(I would like to output via mono cable).
The sample project code may appear close to your needs, but all the important and difficult stuff goes on inside the NRF24 library and hardware. As you don't want to use the NRF24, this sample project is useless to you.
I'm guessing you are not an experienced coder. I suggest looking for libraries which can handle the PPM stuff for you and seeing if any meet your requirements. If you are flexible about your hardware and can consider using a Teensy, then you may find Paul Stoffregen's PulsePosition library a useful starting place. Also see the link at the bottom of the page concerning an alternate library.