Offline Bitcoin ATM

A Bitcoin ATM (coins only) with Lightning Network support, running fully offline on an ESP32. It accepts physical euro coins through a coin acceptor, generates an LNURL-withdraw QR code locally — no internet connection required for operation — and shows it on an e-paper display for the user to scan with any Lightning wallet.

The Lightning Network is a second-layer protocol on top of Bitcoin that enables trustless transactions with instant settlement and cheap fees.

Tip

Just want to flash a device? Open the Web Flasher in Chrome or Edge, connect your ESP32 over USB, and click Install Firmware — no tools to install. See Web Flasher for details.

Where to start

• Building one from scratch? Start with the Bill of Materials, then follow Hardware Assembly and Flashing the Firmware.

• Already assembled the hardware? Jump to Flashing the Firmware and Configuration.

• Want to print a case? See 3D Printed Case.

• Hacking on the firmware? See Architecture.

Getting Started

• Introduction
  • How it works offline
  • State machine
  • Gallery
  • Special thanks
  • Contact & support
• Bill of Materials

Building the ATM

• Hardware Assembly
  • Wiring & Pinout
  • Programming the Coin Acceptor
  • Assembly order
  • Circuit diagrams
  • Construction photos
• 3D Printed Case
  • Parts to print
  • Assembly

Firmware & Setup

• Flashing the Firmware
• Configuration
  • 1. Create the LNbits FOSSA connection
  • 2. Enter the connection string on the device
  • Optional: BlockClock idle display

Extras

• Telegram Notification Bot
  • Prerequisites
  • Setup

Development

• Architecture
  • Dual-core design
  • Modules
  • Key design constraints
• Building & Testing
  • Toolchain setup
  • Build & flash
  • Unit tests
  • Linting
• Contributing
  • Firmware
  • Documentation