Open Telegraph | Chouhan Industries

Open Telegraph board, 3D render — 3D render of the 2-layer board

The Problem

Morse code has no modern hardware.

Telegraph keys are museum pieces or ham-radio accessories. Nothing plugs into the devices people actually use. Learning Morse today means a radio license, a rig, and a wall of legacy equipment before you send a single character.

The oldest digital protocol deserves a first-class input device. Nobody builds one.

The Approach

A single button as a universal keyboard.

Open Telegraph decodes Morse in firmware and presents itself as a standard HID keyboard. USB on the desk, Bluetooth in the pocket. No drivers, no companion software required. It works in any app on any operating system.

It answers one question: can a single button type on your phone and computer? Everything that is not that question was cut.

Architecture

One button. Any device.

Interaction

Everything the user ever touches.

Short Press: Key Double Press: Pair Triple Press: USB / BT Long Hold: Power

Firmware

Turns presses into keystrokes.

Morse Decoder USB HID Bluetooth HID BLE UART Power Management

Hardware

Computing, power, and radio on one board.

ESP32-S3-WROOM USB-C LiPo Charger Tactile Switch RGB LED

Expansion Header

Six pins for everything else.

OLED Rotary Encoder Real Telegraph Key LoRa Sounder

Design

Everything essential. Nothing else.

Core

ESP32-S3-WROOM Module
Native USB
Bluetooth LE
Wi-Fi On Board

Connectivity

USB HID Keyboard
Bluetooth HID Keyboard
BLE UART Channel
No Drivers Required

Power

Rechargeable LiPo
USB-C Charging
Long-Hold Power Off
Deep Sleep Standby

Status LED

Blue: Bluetooth Connected
Green: USB Connected
White: Pairing
Red: Low Battery

Board

2-Layer PCB, ~40 × 40 mm
0603 / 0805 Passives
Large Test Pads
Full Silkscreen Labels
UART Debug Header

Open Files

KiCad Schematic & Layout
Full BOM
Firmware Source
Design Rationale & Errata

SDK

The whole device is an API.

The BLE UART channel is a documented serial protocol, and a small Python library wraps it. Stream letters as they are keyed or adjust decode speed from a script. It is the same interface the companion app uses, open to everyone.

Hardware extends the same way: a six-pin header exposes power, two GPIOs, and a UART, so displays, a real telegraph key, a LoRa radio, or a sounder attach without touching the main board.

Python

import telegraph

# same key over USB serial or BLE
key = telegraph.connect()
key.set_wpm(18)

# letters as they are keyed
for letter in key.listen():
    print(letter)

Roadmap

One key. Built in stages.

Phase 1

Prototype Hardware

Schematic and 2-layer board in KiCad, professional design review, first hand-assembled units and bring-up.

In Development

Phase 2

Firmware Core

Morse decoder, USB and Bluetooth HID, pairing flow, LED states, and power management. Adjustable keying speed.

Planned

Phase 3

Design Files Published

KiCad sources, BOM, firmware, and the full design rationale, including the mistakes and what fixed them.

Planned

Phase 4

Companion App

Settings, decode speed, and firmware updates over the BLE UART channel. The device stays fully usable without it.

Research

Phase 5

Accessories

OLED display, rotary encoder, real telegraph key jack, and mechanical sounder on the expansion header.

Research

Phase 6

Production Run

Assembled units in an enclosure, built from the published files. Anyone can manufacture the same board without restriction.

Research

Built with Claude

Designed with Claude Code open on the repo.

The KiCad schematic, the routing plan, and five design docs that have to stay in sync are all edited as real files, with ERC and DRC checked through kicad-cli. Claude reads the datasheets, holds the constraints, picks the parts, and writes down why each one is there.

One button. Everything published.

Open Telegraph is in active design. Follow the build log, review the schematic, or propose an accessory for the expansion header.

View Repository Build Log