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QUESTION

I built a simple bitshifter in Minecraft yesterday. I wondered if something like this could be built with LEGO?

Maybe there is a possibility to build gates with rubber bands and those movable mechanic stuff. Did anyone of you do something like this?

{ asked by Sibbo }

ANSWER

Various people have done this - however most of the links seem to point to a [then defunct] blog by Martin Howard (Randomwraith) from 2004.

A more recent, and available, post on this, using newer pieces can be seen here:

LEGO Logic by Keshav Saharia

Based on a lack of gears and rack and pinion elements, Keshav decided to rebuild the logic gates using an approach based around levers. Extra care was taken to ensure that the movements were uniform so that the outputs moved the same distance as the inputs.

Starting with the simplest gate, a NOT Gate was built:

2 NOT Gates

Then going back to first principles, a NOR Gate:

A NOR Gate

Combining a NOR with two NOTs gives an AND Gate:

A NOR and 2 NOTs make an AND

Finally Keshav built the XOR Gate out of 3 NORs and 2 NOTs (or 2 NORs and an AND):

The whole XOR Gate

Detail of XOR Schematic

All images used with permission

{ answered by Zhaph - Ben Duguid }
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