Displays & FPC Extension

Each of the 72 keys has a 0.42” OLED display connected to the PCB via a short FPC (flex printed circuit) cable. The displays ship with cables that are too short to reach the PCB sockets, so you need to extend them — or use displays from the kit which already have the correct cable length.

Extended modules, ready to fit:

The easy way: kit displays

Displays from the official kit have the matching cable length and pin count. Skip the FPC extension section below if you are using kit parts.

Sourcing displays yourself

The displays are 0.42” OLED, 14-pin FPC. Known working part numbers:

• FPT042W000Z01
• P34107
• ZJY042-7240TSWPG10 (requires a 40mm extension cable instead of 30mm)

Note

Alibaba listings for these parts often become outdated. If a link is unavailable, search for “0.42 inch 72x40 OLED FPC” and check the pin count and pitch before ordering.

You also need a 14-pin or 16-pin FPC extension cable with contacts on the same side (not reversed), approximately:

• 30mm for most displays
• 40mm for ZJY042-7240TSWPG10

Extending the FPC cable

Extending means soldering each short FPC strip to a longer extension cable with low-temperature solder and a heat gun. Kit displays skip this step.

Caution

Not every display survives the extension process. If you do it yourself, order at least 10% more displays than you need.

The full illustrated step-by-step (solder temperatures, alignment, heat-gun settings and photos) is in the hardware repository — follow it there if you need it:

FPC extension procedure on GitHub →

Status displays (optional)

Two 0.96” displays can be added as status displays — one on each half. Compatible part: FPW096W001Z0 or pin-compatible alternative.

The FPC cable should be approximately 40mm long.

Pin reference for compatible status displays:

PIN	Signal	PIN	Signal
1, 30	N/C (GND)	14	RES#
2, 3	C2P, C2N	15	D/C#
4, 5	C1P, C1N	16	R/W#
6	VDDB/VBAT	17	E/RD#
7	N/C	18–25	D0–D7
8	VSS	26	IREF
9	VDD	27	VCOMH
10–12	BS0–BS2	28–30	—
13	CS#	—	—