SeedSigner Plus smartcard pico

SeedSigner-Plus Smartcard Pico

A single-board SeedSigner carrier ("hat") for the Luckfox Pico Mini. It puts the display, joystick/buttons and a CCID/PCSC-compatible smart card interface on one board, so a self-contained SeedSigner + Satochip device can be built around a Pico Mini instead of a Raspberry Pi.

It is designed for this SeedSigner fork, which adds the smart card (Satochip / SeedKeeper) features: https://github.com/3rdIteration/seedsigner

What's on the board

The camera is not routed on this board — it connects to the Pico Mini module directly.

Display

The board drives the same 2.8" IPS LCD module as the existing SeedSignerPlus display hat, over a 40-pin 0.5 mm FPC connector wired for 4-line SPI (IM0 = 0, IM1 = 1, IM2 = 1).

• Size / type: 2.8" IPS
• Resolution: 240 × 320 (RGB565)
• Controller: ST7789
• Interface: 3/4-wire SPI, 40-pin FPC
• Backlight: white LED

See the SeedSignerPlus display hat readme for the full module specification and 40-pin pinout. The display module is the same as the plus hat, but note that the FPC pinout is not reversed on this board — unlike the reversal noted in the plus hat readme.

Configuration solder jumpers

Three pairs of jumpers let one board match either the on-board display or a Waveshare display hat. The factory default is marked (*) on the silkscreen. Never bridge both options of a pair (the board is silkscreened NEVER BOTH).

SeedSigner currently does not use the backlight PWM and drives the display CS low all the time, so the defaults (backlight from 3v3, SPI CS driven from the Pico Mini) give the best compatibility. The full reasoning is in the schematic notes in rpi_interface.kicad_sch.

In normal use the jumpers can simply be left at their factory defaults — they exist mainly for development/testing or for repurposing this hardware in other projects.

Board and fabrication

• 2-layer PCB, 1.6 mm thickness, rounded handheld outline (approx. 138 mm × 52 mm).
• Fabrication files for JLCPCB are in jlcpcb/: Gerbers, BOM and CPL in production_files/, plus the individual Gerber exports in gerber/.
• KiCad project, created with KiCad 10. The schematic is split across the rpi_interface, smartcard_reader, screen, buttons and Power sheets.
• Footprints/ and Library.pretty/ hold the bundled project footprints/symbols; fp-lib-table and sym-lib-table point KiCad at them.

Assembly notes

• The board accepts the Luckfox Pico Mini in either of two ways:
  • soldered directly onto the PCB, or
  • mounted on an 11-pin 2.54 mm female pin header (easiest is to buy a 12-pin strip and cut the end leg off).
• The Pico Mini mounts MicroSD side up, with its USB-C end facing the board edge. Be sure to follow the orientation markings printed on the board — the photo at the top of this page shows the correct orientation.
• If you use a through-hole pin header instead of soldering the Pico Mini flat, tape over the pins — the LCD housing can otherwise short 3v3 to GND (silkscreen warning).

Enclosure

3D-printable case files live in ../../enclosures/luckfox_pico/plus-hat-smartcard-pico-zero/. See the enclosure readme for part selection and hardware details — the set covers both mounting options (soldered Pico Mini or through-hole pin header), matching microSD covers, a faceplate, and an optional camera cover:

The case is designed for low-profile Pico Mini camera modules. In the photo at the top of this page the two smaller camera modules are the low-profile type the case fits; the larger one is the full-sized type commonly sold for other Luckfox Pico boards and will not fit.

Related hardware

• ../SmartcardHat/ — SEC1210 smart card hat for Raspberry Pi.
• ../SeedSigner+ Smartcard combo hat/ — combined SeedSignerPlus display + smart card hat.
• SeedSignerPlus display hat — Raspberry Pi hat using the same 2.8" IPS display module as this board.
• Smaller Luckfox Pico carrier boards that present a standard Raspberry Pi-style 40-pin header (for use with existing Waveshare hats), from the seedsigner-luckfox-pico repository:
  • Luckfox Pico Mini v2
  • Luckfox Pico Max v2
  • The existing Pico enclosures in ../../enclosures/luckfox_pico/seedsigner-luckfox-pico-mini-max-case/ are designed for those two boards.
• Software support and wiring: ../../docs/hardware_platform_support.md and ../../docs/smartcard_support_installation.md.

Changelog

v1.0.1 — moved the display slightly; added a couple of extra capacitors.

v1.0.0 — initial beta.