Flow-rate meters based on measuring Coriolis-force reactions are widely used in process control systems.
The measurement principles are mentioned or illustrated at numerous web sites, including youtube video e2NGvrkmP8Y, Back to Basics: Flow Measurement (Corilolis) (via oscillating-tube phase changes) and Schenck Americas' Solids Flow Meters page, Coriolis Principle section (via vaned-rotor reaction forces) . Coriolis-based meters measure the delivered mass of solids, liquids, and gases. Delivered volume can be calculated if density is known. Purchase of a Coriolis-based meter seems far more feasible than building one from scratch.
The Schenck page also illustrates impact-plate-based measuring systems and deflection-chute-based measuring systems. These integrate impulses or deflection force to measure flow. Again, purchase seems more feasible than building one yourself.
At a hobby level, I think two approaches should be considered first: (A) calibrate a constant-flow-rate system, and control delivery time; (B) implement a fill-and-dump system, and control number of cycles.
(A) Using a method from previous questions (1,2) set up a system that moves your substance at a reasonably constant rate; measure that rate; thereafter, control how long or how fast the system runs to deliver a desired amount of substance.
(B) Again using methods from previous questions, set up a system to fill a cup, box, chute, or transfer bin some number of times, and dump it into a receiver. Issues like detecting when the cup is full, preventing or recycling overflow of the cup, and dumping the cup arise but can be resolved. The issue of limited resolution (where the delivered amount is an integer multiple of cup size) can be treated by using a smaller cup, or using different cups for different jobs, or using a box with an adjustable side or bottom, or having the box sit on a load cell during filling.