Rotation matrix

From TheAnalogThing
Revision as of 09:30, 25 October 2021 by MKoch (talk | contribs)

Only two dimensions x,y can be shown on an oscilloscope screen. If you have a circuit with three outputs x,y,z you can see only two of them. But with a rotation matrix you can rotate the x,y,z space so that you can see a two-dimensional image from an arbitrary direction.

A 24-step switch can be used for angle adjustment in 15° steps. These 4x24 switches are available on Aliexpress for less than 10€. Search for "4*24 Rotary Switch".

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The switch must be disassembled to remove the limiter, so that the axis can be rotated over the full 360° range.

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In those planes that make the sin() and -sin() signals, the contact must be removed from the A position and inserted in position B, which is 90° phase shifted from A. For the -sin() signal, the phase shift is in the other direction.

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For yaw, pitch and roll rotations you need three switches.

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This is the schematic for half of the switch. It has an input A and two outputs A*sin(alpha) and A*cos(alpha). The schematic for the other half is identical, but the contact in the switch is phase shifted in the other direction so that the outputs are -A*sin(alpha) and A*cos(alpha).

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This is the main schematic:

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