The Scanning Tunnelling Lego


The Probe is a Lego MindStorms robot that can determine the height of each point of an object on a grid. It does this by scanning a head back and forth along the x-axis, moving a little along the y-axis after each scan. For each point along the way it stops and lowers the probe (a long axle) until it makes contact with the object. Counting the time it took to lower the probe gives a measure of the depth at that point. These depth values are logged and transmitted to a NetWinder Linux box for plotting.

The Probe

The subjects: some Thunderbirds models

The objects being probed: some Thunderbirds models

The contour map from The Probe, plotted with gnuplot

3D surface plot of Thunderbirds models

The Probe files:

More photos of the Probe:
Another view of The Probe, showing the x-axis rails and rack Yet another view, showing the probe axle and drive head The clearance underneath the Probe The x-axis drive cog, and the light-sensor that sees black on the rail at the end of its travel The y-axis drive motor, which drives one wheel on each side The z-axis drive motor and worm gears.  The 8t gear does not rotate. The z-axis head, with the probe sensor and axle removed The touch sensors that limit the vertical movement of the probe head.

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Copyright © 1998 Ben Williamson