Reversible PCBs

A reversible PCB is one board design that makes both halves of a split keyboard. Build the left half on one board, flip the next one over and build the right half on that. You order one design instead of two.

Not to scale. Flipping a board mirrors it, controller holes too, so the flipped half has its controller on the other face (dashed). Two mirrored sets of holes let it sit on top on both halves.

PCB makers sell boards in batches of a few copies. With a reversible design any two of them make a keyboard. With separate left and right boards you order both, and a spare left is no use without a right.

It works because most splits are mirror images, and flipping a board mirrors it. The switch holes work from either face. The controller is the tricky part, since flipping the board reverses the order of its pin holes.

Where the controller goes

One set of holes. On the flipped half the controller goes underneath, or stays on top mounted face down. A build photo of the Architeuthis Dux shows one nice!nano face up on the left half and the other face down on the right.

Two mirrored sets of holes, overlapping, so the controller sits face up on both halves. The Cradio Z lp does this: its controller footprint has two full sets of 24 holes. It isn't recorded in the catalog yet, so it's not in the lists below.

Some splits can't be reversible because the halves carry different parts. The Ferris has the chip and USB-C port on the left and an IO expander on the right.

Recorded by hand, one design at a time. Not recorded yet for 122 of the 131 split designs.

Recorded as one reversible PCB 1

★ 239 architeuthis dux by tapioki 34 keyssplit

Recorded as two different PCBs 8

3 of 8 shown. The catalog has no filter for this list yet.