Water Game

Enter the Water Garden: a water cannon game with a twist. The goal was to make a three- or four-person game where kids would aim their water cannon to targets in front of them that change around. The very first incarnation of the concept shown below was pretty basic, but ended up not too far from the final implementation:

Players aim their cannon at the panel in front of them and try to hit the "active" target with the water jet. Once the target is hit, it switches (randomly) to another target. A countdown timer stops the water flow after 1 minute. The more targets players hit in that time, the more prize tickets they get. Plus they can compete with each other to see who has the highest score! Here's a video to show this concept during early testing:

How It Works

Water Flow: A water reservoir (45-gallon bucket from Home Depot) has 3 water pumps, one per cannon. I found that submersible water pumps intended for garden fountains were the best combination of power, durability, and price. Water hits the target panels and flows back down to the reservoir through corrugated roofing and a piece of K-style gutter to collect all of it.

Targets: The original concept was to have targets that would light up to indicate which was the active one. However, this game is used outdoors (in sunlight), so making the lights bright enough to be visible was a challenge. The solution was to accomplish this mechanically and use a rotating ring painted with white and red sections that were visible through small windows in the panel to indicate which target was active. An Arduino UNO board senses the position of a spring-loaded switch and commands a servo to turn to the right position. Here's an early video of how this works:

Water Cannons: The cannons themselves are made using 3/4" PVC pipes and fittings, mounted on a rotating turret. After some initial testing with kids, it became clear that I needed to add "stops" to the travel of the turret to prevent them from aiming the water cannons at each other 😃.

Code: The Water Garden runs on three Arduino UNO boards (one per player). The Arduinos handle the following functions:

Turns on and off the relay powering the water pump

Senses whether one of the 3 targets of that player has been hit by the water stream

Controls one of 3 servos that rotate the painted wheel to indicate if the target is active or not

Controls a fourth servo for keeping score for that plater

Senses the position of the reset switch for that player

These functions are incorporated into about 250 lines of code and compiled with the standard Arduino IDE.

The Outcome

Assembly at the actual carnival event took longer than expected but after some creative thinking to address sloping-ground issues, it was completed. It proved difficult to keep the curious kids helping during carnival set up from coming over and trying to play with the game before it was assembled.

The game was a resounding success. We had a constant line to play with it and the same kids kept coming back over and over (and over) to play. The game generated several thousand dollars in revenue to benefit the school.