Labyrinth

Revision as of 09:12, 22 August 2013

The labyrinthgame is is a tilt controlled ball that roll in a wodden labyrinth.

Introduction

The game was initailly operational in 1999 using an analog camera, a framegrapper and a DOS operating system, controlling DC motors to perform the roll and tilt needed to follow a predefined route. The interface used a dedicated DA and digital interface board.

The present modification uses a firewire camera Guppy-36C connected to a Linux PC, controlling the same DC motors, in about the same way. The interface is now USB to an Atmel Mega32U4 (a Teensy-2 board) and a few external components.

A stepper motor crane can move the ball to the game.

Description

@todo

Test results

Timing test camera and ball finder

The camera runs with a shutter time of 250 and a gain of 64 (both camera units), this gives a good image with no saturation in normal in-door light.

The firewire packetsize is set to 1250 bytes and this allows about 200 frames per second on a 60 lines by 752 columns image. Taking the slize with the ball.

The ball finder process shows (in a logfile transferred to file server over the wired net) a stable 5ms between each frame (i.e. full camera speed)

Timing test, USB interface to Atmel board

From a command is transmitted to a status reply is received, no more than 0.5ms is seen. Sending 3 commands in one go, the reply of the first is within 0.5ms and remaing 2 are received with 0.05ms interval, suggesting that most of the 0.5ms is spend on the USB connection, rather than on the Atmel board.