Improvments in plastic/metal seperater process

[SimarGill]

Good evening, Please see the picture attached. The two right sensors are capacitive and photo sensor. I want to replace them into a color sensors or some other type of sensors. What the system does is that the cylinders extend and pick up the a bearing and using the far left sensor (inductive) it separates them in the appropriate location on the left side. So the two right sensors are pretty useless. I want to replace into another type of sensor and utilize the junk section as well. If anyone can give me any links or some information on what sensor would be appropriate that will be great. I will be using Omron CJ2M - CPU31 to program the sensors. Thank you!