The first rev of this project is to make 25 balloons inflate and deflate randomly on a 2' x 2' wall.

I was given 100+ SMC solenoid valves from a decommissioned piece of equipment for free along with some other miscellaneous pressure/ vacuum fittings etc.

I was originally planning to use 25 3 port solenoid valves for intake (inflate) and outtake (deflate) both. To go between the two states was merely a pin toggle.

It quickly became noticeable that toggling didn't also have a "stop" setting. With a 3 port solenoid valve, you get 2 states, flowing in or flowing out. So there wasn't a way to control how much flow in either direction.

Another issue was that the outtake port didn't have a big enough aperture to let out enough air (1.25mm). So the balloons were inflating quite quickly through the tiny 1.25mm hole but not deflating. Since this wasn't lively enough to make a good display, we had to purchase higher flow solenoids for the outtake (deflate). These new solenoids are only used on the outtake and have a 2.5mm aperture. Plus they take 1/4" tubing while the intake uses 3/16" tubing.

I'll update this log soon with all the fittings.

And this created a new issue with the coding. When before there had been something basic, with just on/off toggle (written by John Wasser), now there is a new thing to do.

Each solenoid valve is now paired. When one is intaking, the counterpart must outtake. And all of these are on random times. I got quite a lot of help at the Arduino forum Sophi: begging for coding help and finished it up.