sounds like roll-your-own is the best bet here

It's for a production line production-like environment. It's an academic project where a large quantity of sensors is made for a study. The rig already has two sensors which communicate to a PC through USB virtual COM port. There's no PLC or some kind of DAQ which can pick up "raw" electrical signal like analog voltages or high-low. I’d like to connect the sensor to the PC without having to create [and - worse yet - to maintain] another piece of uC firmware.

I’ll ask the fellow who curates the software what he would prefer, and what he’s willing to put up with.