# How to control the timed release of small bubbles in a liquid?

I'd like to have electronic control of the open/close timing of a source of air at the bottom of a tank of liquid such that I have control of when a single bubble is formed.

Experimentation would be required but I expect the open period to be at most 250ms - the more scope for lower period options the better.

The process of bubble forming would be repeated over and over again - with a 50% duty-cycle the frequency of new bubble formation would be a minimum of 2Hz.

Let's say 5~10Hz would be ideal.

Multiple bubbles will need to be formed in close vicinity (~10mm) so the device would either have an appropriate form-factor, or some kind of tubing system would be put in place.

I will have close to arbitrary control over the control signals, but I expect some form of digital control per 'channel', preferably parallel and direct, i.e. 0=closed, 1=open, as opposed to some kind of interpreted data stream.

Although I understand that the dynamics of bubbles will be all over the place, in terms of control I'd expect low latency.

Question: what kind of devices am I looking at here?

Are there off the shelf components that can do this? Cost is a concern at some level but is not necessarily the overriding requirement.

• D you mean something like what is used in this clip: youtube.com/watch?t=4&v=gRSKgxgB42k? This is part of research conducted by Professor Timothy Leighton at the University of Southampton – atom44 Oct 2 '15 at 13:54
• Hook an aquarium bubbler up to a variac? – grfrazee Oct 2 '15 at 16:09
• @mg4w that looks pretty good yes. Thanks! I'll follow that up certainly. – Lamar Latrell Oct 2 '15 at 22:57
• @grfrazee I considered that, but made the assumption that a system like that would have lag and the bubbles would be too big? – Lamar Latrell Oct 2 '15 at 22:58
• No idea, just throwing it out there. – grfrazee Oct 2 '15 at 22:59