Qeychain hardware keychain front
Qeychain front view
Qeychain PCB detail

OPEN SOURCE HARDWARE // PROTOTYPE

Qeychain

Keychain-sized Solana signer with hardware-secure key storage, OLED display, and one-button token operations. Keys never leave the secure element — ever.

Status Prototype
Request Device View Repository

Processor

ESP32-S3

Security

OPTIGA Trust X

Display

SSD1315 OLED

Network

Solana / Bags API

PRODUCT DESCRIPTION

A keychain that signs transactions the right way

Qeychain puts a hardware-grade secure element in your pocket. Private keys are generated and stored inside the OPTIGA Trust X chip — they never touch the MCU, never travel over USB, and never leave the device.

Overview

Qeychain is an open-source keychain-sized hardware device designed for Solana developers and power users who want true hardware security without the bulk of a full hardware wallet. It combines the ESP32-S3's wireless capability with the OPTIGA Trust X secure element's cryptographic enforcement to keep signing operations fully air-tight.

Built around the Bags API, Qeychain enables one-button token launches, live token feeds on the OLED display, and fee management — all from a device small enough to live on your keys.

Key Features

  • One-button token launches via the Bags API
  • Live token feed display on OLED
  • Hardware-signed transactions — keys never leave the secure element
  • Fee dashboard and claims management
  • Fee share configuration updates
  • Dual-button navigation (SW1 and SW2) for on-device confirmation
  • RGB LED and buzzer for visual and audio feedback
  • Open-source PCB — inspect, modify, or self-assemble

Hardware Specs

  • ProcessorESP32-S3 microcontroller with Wi-Fi and Bluetooth LE
  • Secure ElementOPTIGA Trust X — hardware crypto key storage, keys never leave the chip
  • DisplaySSD1315 OLED — shared I2C bus at address 0x3C
  • InputSW1 (GPIO38) and SW2 (GPIO39) — active-low with hardware pull-ups
  • FeedbackWS2812B RGB LED (GPIO48), status LED (GPIO47), buzzer (GPIO21)
  • ConnectivityUSB-C for power and data
  • I2C BusGPIO15 (SCL) and GPIO16 (SDA) — shared between OLED and secure element
  • Expansion13 free GPIO pins across breakout headers H1 and H2

In the Repository

  • Schematic PDF (Qeychain_SCH.pdf)
  • Bill of materials (BOM_QEYCHAIN .xlsx)
  • Gerber files for manufacturing (Gerber_Qeychain_X1.zip)
  • Front and back board renders
  • GPIO pin reference for Rust firmware development

Getting Started

  1. Clone the repository and review the schematic PDF.
  2. Use the BOM and Gerber files to source components and order PCBs.
  3. Flash the ESP32-S3 using the provided firmware references.
  4. Pair with the Bags API for Solana token operations and signing.
  5. Use GPIO pin references from the README during firmware bring-up.