Water cannon with app

The oldest and still most popular demo project of our customers is the water cannon from 2012: an adjustable water nozzle that can be controlled via a joystick in the center console of an old VW Passat (1990).

The water nozzle is hidden behind the VW emblem. When activated by the joystick the emblem flips out in an instant and is ready for action.

The direction of the water jet can be controlled with a joystick in the car's center console or via an iPhone app. When controlled by smartphone, the cannon aligns itself according to the tilt of the accelerometer.

The spacious engine bay houses the technology. Electronics, pump and water tank find their place here.

The high-pressure pump draws from a 10 liter canister and pushes the water through the nozzle at 6 bar. The range of the water jet is 12 meters.

Servo motors from the model-building supply are used as actuators for the X and Y axes.

The electronics consist of a Wi‑Fi router, an Arduino board with Ethernet shield, and the microcontroller ATMEL AVR ATMEGA 8.

For low-level hardware programming C++ was used and for the app a JSON scripting language. Data exchange between the iPhone and the electronics is done via UDP packets in OSC format.

All mechanical parts were produced with the CNC milling machine.

Compared to a conventional VW emblem, the repurposed one shines in a bright red. The water jet glows at night in a vivid blue LED light and resembles a lightsaber.

The water cannon combines classical mechanical engineering with modern information technology and shows, with a wink, how useful engineering can be.