Using the Java applet on the right you can pick out the differnet components of the LightScan

I wanted to wait until I had an additional light sensor, motor and a rotational sensor before I built LightScan.With the additional component it would be easy to compare readings from each light sensor and rotate the vehicle to line up with the sensor turret.

But it looks like it will be a while before i can get any additional Lego®, so Lightscan is built completely from the Robotics Invention Kit 1.5

The most difficult part of LightScan is the programming, which could not be done with the usual graphical interface.
There are a few differnet options if you want to program the RCX brick and I choose the Lego® SDK (software development kit) direct from the Mindstorms® website.
With this script language I created a program that would follow the following steps.

1: Read in the value from the light sensor mounted at the front of LightScan
2: Compare that value with any previous readings
3: Turn and move towards the best value

All the while check for presses of the button, which mwould change the search from light to dark and vise versa

I had some trouble in intitial testing that proved to be simply the cogs very in reverse order, so a Large cog connected to the motor was connected to a small cog on the track, which increased speed but lowered power so much even the tracks would not turn, even if the whole unit was not touching the ground.

After swapping the cogs around the unit had plenty of power on which to drive and happily went off in search of bright lights (unitl i pressed the button and it went in search of dark places).

The Mindscript® code can be found here and the java applet source here

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around LightScan
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