A wrist-wearable Raspberry Pi Zero smartwatch with an e-ink display that generates Wi-Fi voucher codes on demand.

PiSpot Watch is a custom-built wearable IoT device designed for hotel and venue staff. Press a button on your wrist and instantly generate a time-limited Wi-Fi voucher code, displayed on a low-power e-ink screen. The device communicates with the Spotipo captive-portal API and retrieves per-device configuration securely from HashiCorp Vault.

Originally developed and deployed in 2018 for the company GPConnect, this project has been released as open-source. It is part of the PiSpot ecosystem:

• Wearable form factor -- fully 3D-printed wristwatch case housing a Raspberry Pi Zero, PaPiRus e-ink HAT, and battery.
• One-press voucher generation -- each of the 4 configurable buttons creates a voucher with different duration presets via the Spotipo API.
• E-ink display -- 2.0" PaPiRus Zero electronic paper screen; always readable in sunlight, ultra-low power draw, holds image with no power.
• HashiCorp Vault integration -- per-device secrets (API keys, button mappings, speed limits) stored centrally and fetched at runtime via AppRole authentication.
• Low-battery shutdown -- JuiceBox battery monitor triggers graceful poweroff before the battery dies.
• Centralized logging -- FluentBit ships rotating logs to a remote aggregator.
• Ansible deployment -- single playbook provisions the entire device: drivers, services, Vault credentials, WiFi, power management.
• Power-optimized -- GPU memory reduced to 16 MB, HDMI disabled, ACT LED off, event-driven GPIO (no polling).

See all photos in docs/photos/.

  Button press (GPIO interrupt)
         |
         v
  +------+------+
  | HashiCorp   |   Fetches device config:
  | Vault       |   API key, button mappings,
  | (AppRole)   |   speed limits, duration presets
  +------+------+
         |
         v
  +------+------+
  | Spotipo     |   POST /api/voucher/create/
  | WiFi API    |   --> returns voucher code
  +------+------+
         |
         v
  +------+------+
  | PaPiRus     |   Renders duration + code
  | e-ink       |   on 2.0" e-paper display
  | display     |   (holds for 30 seconds)
  +-------------+

1. The device idles in a low-power loop, waiting for a GPIO falling-edge interrupt.
2. On button press, it connects to Vault and retrieves the device's secret configuration by hostname.
3. It POSTs to the Spotipo API with the voucher parameters mapped to the pressed button.
4. The voucher code and duration are rendered on the e-ink display for 30 seconds, then the screen returns to the logo.

The Case/ directory contains everything needed to print the wristwatch enclosure:

Multiple case variants are included (3 Cases.gx, 7 Buttons.gx) for different button configurations.

git clone https://github.com/GeiserX/PiSpot-Watch.git

Use PiSpot Deployment to configure per-device secrets in Vault, or manually create a KV secret at pispot_voucher/<hostname> containing the Spotipo API key, button duration mappings, speed limits, and site number.

ansible-playbook -i inventory deployment-files/main.yml

The playbook handles:

• PaPiRus driver compilation (gratis V231_G2) and SPI/I2C enablement
• Python dependencies (RPi.GPIO, requests, hvac)
• pispot.service systemd unit (auto-starts after epd-fuse)
• JuiceBox low-battery shutdown service
• FluentBit log aggregation
• Vault AppRole token bootstrap and weekly renewal cron job
• WiFi configuration and power optimizations

PiSpot-Watch/
  main.py                          # Main application (GPIO events + API calls + display)
  deployment-files/
    main.yml                       # Ansible provisioning playbook (288 lines)
    get-approle-token.py           # Unwraps Vault AppRole wrapped secret ID
    vault-renew-token-pi.py        # Weekly Vault token renewal (cron)
    pispot.service                 # Main app systemd unit
    low-battery-shutdown.service   # JuiceBox battery monitor unit
    papirus-clear.service          # Clears e-ink on shutdown
    td-agent-bit.conf              # FluentBit log shipping config
    wpa_supplicant.conf            # WiFi network config
  Case/                            # 3D enclosure (FreeCAD + Goxel + STL)
  docs/images/                     # Documentation assets
  extra/                           # Logo
  LICENSE                          # GPL-3.0

GNU General Public License v3.0

@GeiserX

Contributions are welcome. Open an issue or submit a pull request.

This project follows the Contributor Covenant v2.1 Code of Conduct.