Car Washing Machine

Introduction

Nowadays, we can easily get our cars cleaned at a car wash. Regardless of whether we have a compact car, sports car or a SUV, car washing machines adapt to our car's size. This requires that its dimensions are accurately measured. Using fischertechnik pieces (a construction toy originating from Germany), I have built a small car washing machine to showcase this measurements.

Measuring the dimensions of each car

Beforehand, different sensors scan the car to measure its dimensions. This includes measering:

• Shape and height

• Width

• Wheelbase

Shape

The individual shape of any car is scanned by two laser light barriers. While the gantry is moving from the front towards the back of the car, the optical barriers are vertically adapted to the car's heigth. Check out the video above to see how the measurements works!

As the raw scan looks pretty rough, there is a post-processor running an antialiasing algorithm. Afterwards, the shape of the car looks more realistic, which allows smooth positioning of the horizontal brush while washing the car.

Width

The car's width is measured by an ultrasonic distance sensor.

The machine

As the fischertechnik system does not provide brushes, I have used paint rollers from a hardware store. In total, there are three brushes that can be either moved vertically and horizontally in order to adapt to the car's size. The brushes are mounted at a gantry that can be moved forwards and backwards.

The machine is controlled by two fischertechnik TX controllers. In future versions of the machine, these microcontrollers will be replaced by an Arduino.