OpenLatch

Electronic door lock system for hackerspaces. Controls physical entry via NFC cards, making access decisions locally on an ESP32 while keeping membership and rules management on a central backend server.

Key Features

• Offline-first: ESP32 makes access decisions without network, using a cryptographically signed allow-list
• NFC access: MIFARE DESFire EV2/EV3 cards with Wiegand reader (production) or PN532 (dev)
• TOTP/HOTP keypad: Backup access via time-based codes and indexed backup codes
• NUKI Smart Lock Ultra: BLE-controlled deadbolt
• Scheduled access: 4 time slots per entry, day masks, overnight support, grace periods
• Cryptographic signing: Ed25519 signatures with sub-key delegation, air-gapped master key

Documentation

• Architecture — system overview, components, data flow
• API — backend REST API reference
• Hardware Setup — production hardware wiring and configuration
• Hardware Setup (Dev) — dev environment with PN532 reader
• Diagrams — state machines, communication flows, sequence diagrams
• Threat Model — attack surfaces and mitigations
• Glossary — project terminology

Use Cases

11 documented use cases covering member access, guest management, emergency access, and administrative operations. See the Use Cases section in the sidebar.

Architecture Decision Records

9 ADRs documenting key technical decisions from monorepo structure to door hardware modes. See the Architecture Decisions section in the sidebar.