How do I make a device to shoot or propel water balloons (that dont kill people!) from a mounted Position?

Because i Have made a treehouse and want something to put on it that fires water balloons on a swivell or hinge of some sort I have seen Some things like waterzookas that shot at 500 miles per hour But that hurts SOOOOO Also it needs to be able to be both of the following able to be fully functioned by on person accurate for at least 30ft weather proof or resistant

Yukondano27 years ago
Build a pressure cannon from pvc and pressurize based on the distance.
Tombini8 years ago
try somthing like a wooden trebuche or catapult maybe even a slingshot, you obviosly want a simple and safe design so these would be my first choices