Waveshare ESP32-P4 4.3" Hardware Wallet Case – Kern / Specter DIY / SeedSigner + RFID2

Waveshare ESP32-P4 4.3" Hardware Wallet Case – Kern / Specter DIY / SeedSigner + RFID2

This enclosure was designed for the Waveshare ESP32-P4-WiFi6-Touch-LCD-4.3 board, with hardware-wallet and air-gapped signing projects in mind.

The design includes space for an internal 602030 Li-Po battery and an M5Stack RFID2 NFC/RFID module, while keeping the device compact and fully enclosed.

Designed for

The enclosure was created primarily for use with:

• Kern Wallet

• Specter DIY

• SeedSigner

Firmware compatibility

At the time this model was published, Kern is the only one of these projects with native support for the Waveshare ESP32-P4 4.3" board.

Specter DIY and SeedSigner do not currently support this hardware natively, but the enclosure was designed with possible future compatibility and experimentation in mind.

Kern currently provides native support for the Waveshare ESP32-P4 4.3" display.

NFC / RFID2 support

The enclosure also includes a dedicated mounting position for the M5Stack Unit RFID2, based on the WS1850S and communicating through I²C.

Important: At the time of publication, Kern, Specter DIY and SeedSigner do not provide native firmware support for this RFID2/NFC module.

There has, however, been interest in adding NFC/RFID functionality to projects such as Kern and Specter DIY, so I designed the enclosure to already accommodate the module for future development and experimentation.

Parts required

• 1× Waveshare ESP32-P4-WiFi6-Touch-LCD-4.3 https://s.click.aliexpress.com/e/_c400jjFD

• 1× 602030 Li-Po battery https://s.click.aliexpress.com/e/_c3w0lDCx

• 1× M5Stack Unit RFID2 https://s.click.aliexpress.com/e/_c4nVzhtl

• M2.5 × 5 mm screws https://s.click.aliexpress.com/e/_c3kS0ogX

• 1× 5-pin Arduino-style male pin header https://s.click.aliexpress.com/e/_c3BrBwwL

• Wires/cable supplied with the M5Stack RFID2 https://s.click.aliexpress.com/e/_c4SDNBiB

RFID2 wiring

The RFID2 communicates through I²C.

My connection between the Waveshare board and the M5Stack RFID2 is:

Waveshare header	RFID2 cable
Pin 1 – 3.3V	Red
Pin 2 – SDA	Yellow
Pin 3 – SCL	White
Pin 4 – Not connected	—
Pin 5 – GND	Black

In other words:

3.3V → Red
SDA → Yellow
SCL → White
Pin 4 → Not connected
GND → Black

The M5Stack cable normally identifies the red wire as the module power wire, yellow as SDA, white as SCL and black as GND.

For my build, I connected the RFID2 power wire to the 3.3V pin of the Waveshare board.

Please verify the electrical requirements of your specific RFID2 module/revision before reproducing this wiring.

How I connected the RFID2

To make the internal connection compact and removable, I used a standard 5-pin Arduino-style pin header.

I shortened the pins slightly and connected the RFID2 cable wires in the following order:

Waveshare:
[ 3.3V ][ SDA ][ SCL ][ NC ][ GND ]
RFID2:
[ RED  ][YELLOW][WHITE][ -- ][BLACK]

This creates a simple internal connector without requiring the RFID2 cable to be permanently soldered directly to the Waveshare board.

GitHub projects

Kern Wallet
Experimental ESP32-P4 based air-gapped Bitcoin signing project.

https://github.com/odudex/kern

Specter DIY
Open-source DIY Bitcoin hardware wallet / signing device.

https://github.com/cryptoadvance/specter-diy

SeedSigner
Open-source air-gapped Bitcoin signing device.

https://github.com/SeedSigner/seedsigner

Notes

This enclosure is intended for DIY and experimental hardware-wallet development.

Firmware support can change quickly, especially for the ESP32-P4 platform and NFC functionality, so check the respective GitHub repositories for the latest hardware compatibility before building.

If future Kern, Specter DIY or SeedSigner releases add support for the RFID2 module, the hardware space and mounting position are already available in this enclosure.