Optional - Keypad

A 3x4 matrix keypad enables scan-to-tool assignment for toolchanger and multi-tool setups.

What You Need

• 3x4 membrane matrix keypad (this one on Amazon is confirmed working)
• 7 jumper wires

Wiring

The keypad ribbon cable has 7 pins. The labels printed on the ribbon (left to right) are:

C2  R1  C1  R4  C3  R3  R2

Wire each pin by its label, not its position on the ribbon.

ESP32-WROOM

Ribbon Label	ESP32 GPIO	Function
R1	GPIO 19	Row 1
R2	GPIO 15	Row 2
R3	GPIO 16	Row 3
R4	GPIO 5	Row 4
C1	GPIO 18	Column 1
C2	GPIO 21	Column 2
C3	GPIO 17	Column 3

Pin assignments changed in v1.6.4

If you wired your keypad before v1.6.4, you'll need to re-wire to match the new pin assignments above. The pins were rearranged to match the physical order of the keypad ribbon connector.

ESP32-S3-Zero

Ribbon Label	ESP32-S3 GPIO	Function
R1	GPIO 38	Row 1
R2	GPIO 39	Row 2
R3	GPIO 40	Row 3
R4	GPIO 41	Row 4
C1	GPIO 17	Column 1
C2	GPIO 18	Column 2
C3	GPIO 42	Column 3

Tip

The ribbon labels are not in order (C2, R1, C1, R4, C3, R3, R2). Match each label to the correct GPIO — don't wire them left to right.

Warning

Using LCD + keypad together on the ESP32-S3-Zero is not recommended due to limited GPIO...it can be done but soldering to the exposed pins on the back is tough. Use the WROOM board for LCD + keypad builds.

How It Works

1. Scan a spool on the NFC reader
2. Type the tool number on the keypad (e.g. 12 for T12)
3. Press # to confirm
4. Scanner sends ASSIGN_SPOOL TOOL=T12 to Moonraker
5. Press * to clear and start over

Requirements

• Moonraker URL must be configured (web config or installer)
• ASSIGN_SPOOL macro must be defined in your Klipper config
• Keypad enabled via installer or web config (/config > Hardware > Keypad toggle)