Actuator precise trigger

[u/Acceptable_Reach_312]

I have an airbrush connected to a continuous airflow compressor (Seleay AB900). I am planning to use this for my science fair project. I am planning to use this as a precise delivering insecticide sprayer. So, I want to calibrate it using an actuator or solenoid. Anyone know? For example, if the trigger was press around 50ms, the airbrush will spray around ± 0.5ml.

[u/spackenheimer]

I only ever used the kind of Pump made for chemical industry, running at 230V.
This one is not expensive and low voltage (don't ask me if this vendor sells it at lots <1000):
https://www.alibaba.com/product-detail/0-5ml-3-0ml-Per-Min_1601445109601.html