We build an Arduino and VVVV based steering mechanism to conrol a laser and write letters on a surface (like a wall, a building, etc). Due to the fact that the speed of the servo motors is limited it is not possible to get the writing that fast that you can read it. To overcome this issue and visualize the writing we use a long exposure time.

To realize the steering mechanism two servo motors are used: One for the x-direction and one for the y-direction. The laser is mounted on the y-servo which is glued on top of the x-servo. Two PWM outputs of the Arduino are used to control the servos and another one to turn the laser on respectively off. The Arduino runs with the „StandardFirmata“.

The LED in the diagram represents the Laser.

The software of our sideproject consists of two parts:

The first part is the Laser Control patch. This patch is a subpatch we later used in the Laser Type patch. The purpose of this patch is to control the laser and the two servos. It has the following input pins:

• Laser — Turn laser on (= 1) and off (= 0) or dim it (> 0, < 1).
• X, Y — Coordinates where the laser shoult point. Values must range from –1 to 1.
• ProjectionXMin, ProjectionXMax — Let’s you control the size of the projection (how far the servo moves at the maximum values –1 and 1).
• ProjectionYMin, ProjectionYMax — Same purpose like the pins for the X direction.
• Enable — Enables the arduino.
• Reset — Resets the arduino.

This patch is the main patch of our software. It uses the Laser Control patch to write letters with the laser and visualizes the what the laser will draw in a renderer.

In order to disable the laser between two letters we use one typospread for each letter, so we exactly know when a letter ends (after 150 (DotCount) dots). The left part of the patch is used to shift each letter to the correct position.

The center part of our patch generates the dots and sends them to the Laser Control patch. The right part of the patch finally walks through all points and disables the laser while moving from one letter to the next.

You can download the VVVV Patch here: Laser Type