I've got some nice custom hardware that facilitates computer control of a Waters 515 pump. Please check it out here: https://www.ebay.com/itm/205116255767

I also offer the controller for your DIY install on your own pump: https://www.ebay.com/itm/205097247078

I'm interested to obtain feedback from other HPLC users on how useful this can be. I originally built this to run gradient experiments on a home built instrument.