I have a few options here for you.
RP Sorting machine: It can sort automatically, but it requires power.
RP Filter with Item detector at the back ( MUST use a redstone tube between filter and item detector: When an item flows through, the item detector will pulse, which will let the filter pull again. Set a timer of 10-30 seconds to reactivate.
Filter-Buffer-Filter combo: This will auto-pull depending on how full the buffer is and thus doesn't require reactivation.
InputChest (wooden pipe) to RP Relay: Won't require pulses or power, but when the items clog up in the relay, items will get spilled by the wooden pipe.