WaiverServ

This is the system the greets you when you enter the building, and prompts you to sign a liability waiver. It's boring but critical infrastructure to Freeside's long-term survival.

Hardware requirements

• a Raspberry Pi 4 model B
• a portrait-oriented monitor
• a Topaz signature pad

Running

nix run .

Or in a dev shell: nix develop then ./main.py.

Signed waivers are written to $WAIVER_SAVE_DIR (required) & uploaded to a Google Shared Drive; see gdrive-sync.md for the one-time setup.

SD card image

nix build .#nixosConfigurations.waiverserv.config.system.build.sdImage

Building on an x86_64 machine requires binfmt_misc for aarch64 (boot.binfmt.emulatedSystems = [ "aarch64-linux" ]; on NixOS), but only the uncached bits are built under emulation.

You may wish to set up nixbuild.net for fast native builds.

Flashing the SD card

The build leaves a compressed image in result/sd-image/. Write it to the card (replace /dev/sdX with the card's device — check first with lsblk so you don't wipe your whole disk!!):

zstdcat result/sd-image/*.img.zst | sudo dd of=/dev/sdX bs=4M status=progress conv=fsync

Then put the card in a laptop and add wifi.txt and your authorized_keys to the FIRMWARE partition before first boot; see sd-card-config.md.

Updating a running kiosk

nixos-rebuild switch --flake .#waiverserv --target-host admin@192.168.1.101 --sudo

Testing without a signature pad

The pad is read from /dev/topaz. A FIFO at that path plus fakepad.py substitutes for the hardware:

sudo mkfifo /dev/topaz && sudo chmod 666 /dev/topaz
./main.py &
./fakepad.py