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Open Locker

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10 Feb 2026

Architecture

The technical details of our setup.

While building Open Locker, we focused on making the system user-friendly, secure, and reliable.

System components

  • Mobile app (main interface): A simple app for everyday tasks such as opening compartments, borrowing items, and checking their status.
  • Admin panel: The management interface for creating locations, registering devices, assigning roles, and supporting users.
  • Backend: The backend checks permissions, manages state, and provides the API to keep everything running.
  • MQTT broker: Routes messages between the backend and locker locations.
  • Locker client: Runs on a Raspberry Pi at the locker and translates MQTT messages into Modbus commands for the hardware.

Planned:

  • QR code scanner directly at the locker (optional).

Data flows

Command (open, reserve, …)

When a user performs an action in the app, such as opening a compartment, the command follows this path:

AppBackend (HTTPS/REST)MQTT BrokerLocker ClientModbusLocker/Lock

Status (feedback & live updates)

Status updates travel back through the system and can be shown live in the app:

Locker/LockLocker ClientMQTT BrokerBackendDatabaseReverb/WebSocketApp

What runs where?

  • Backend + admin UI + database + MQTT broker: typically central (server/hosting).
  • Locker client: on site on a Raspberry Pi.
  • Mobile app: with the users.