Need an 8 channel PPM encoder for Pixhawk.
https://www.hobbyking.com/hobbyking/store/__8354__X8D_2_4GHz_trainer_port_X8_hack_module_PPM_Only_.html (https://www.hobbyking.com/hobbyking/store/__8354__X8D_2_4GHz_trainer_port_X8_hack_module_PPM_Only_.html)
(http://www.hobbyking.com/hobbyking/store/catalog/62753.jpg)