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Matrices and Duplex Matrix

Improving upon their design.

Maximizing the matrix

  • For non-macropad keyboards, routing a matrix with one pin per row and column will almost always lead to inefficient results.
  • With the same number of keys, a more "square" matrix will require less cols and rows total than a more "rectangular" one.
    • I.E. For 30 keys, 5x6 is 11 pins, while 2x15 is 17 pins.

The Duplex Matrix

  • Each "column" spans two physical columns.
  • Two "rows" exist for each physical row.
  • See schematic at bottom for a routing example.


  • Fit more keys for rectangular keyboards using less pins
  • More pins to use for fancy features
  • Use cheaper controllers to reduce the final product cost


  • More complicated to wire
  • Can be more difficult to add more keys to the matrix later on
  • Harder to follow on a schematic