Automated fluid dropper
I want to release droplets of water one-by-one on command, and have been doing some research on how to do that, but I'm wondering if anyone has some other ideas or has heard of a ready-made solution.
So far I have come across:
-peristaltic pumps with really low flow rates, like the one here
It goes down to 0.09 ml/minute, which should be small enough. I can selectively turn the pump on and off, feeding water to a small tube or dropper end, producing the water drops. These are pretty expensive, the cheapest one I've seen is around $60.
-DIY systems like the one pictured here
with a solenoid opening and closing a safety pin on a tube.
Maybe I could tune the distance of the solenoid so it just opens the pin a tiny amount, and a drop or so is allowed through.
-or I could use a more typical water pump, attach it to something with a really small aperture. I could turn the pump on and off. I have a hard time picturing drop-by-drop control with this, I might be able to release very small amounts, and maybe some 2nd reservoir between the motor and dropper could be designed to aid this.
Is there a ready-made solution to what I'm trying to do? If I just get a regular water pump what should I look for? Ideally I'd like to get a pump that's as quiet as possible, too.