Water cannon with app

The oldest and still most popular demo project from our customers is the water cannon from 2012: an adjustable water nozzle that can be controlled by 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 stream can be controlled with a joystick in the car’s center console or via an iPhone app. When controlled by smartphone, the cannon aligns with the tilt of the accelerometer.

The tech is housed in the spacious engine bay. Electronics, pump and water tank find room here.

The high-pressure pump draws from a 10-liter jerry can and pushes the water at 6 bar through the nozzle. The water stream reaches 12 meters.

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

The electronics consist of a Wi‑Fi router, an Arduino board with Ethernet shield, and the ATMEL AVR ATMEGA8 microcontroller.

C++ was used for low‑level programming and a JSON scripting language for the app. Data exchange between the iPhone and the electronics takes place via UDP packets in OSC format.

All mechanical parts were produced on the CNC milling machine.

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

The watercannon combines classic mechanical engineering with modern information technology and, with a wink, demonstrates how useful engineering can be.