ToGo-Lab FireFly Morse Blinker

DIY kit: ATtiny-based Morse blinker. Through-hole. No mains. Simple on purpose.
Default license: CC-BY-NC-4.0

Intro

This is my “Hello World” hardware project on the new ToGo-Lab server.

Years ago I built a tiny Morse throwie: ATtiny + one LED + one resistor, plus firmware. This version adds a supercapacitor and small solar cells. It uses the LED as a light detector, so it only blinks in the dark.

It's not a throwie anymore. Hang it anywhere with decent light (for charging) and dry conditions and let it blink Morse on its own during night.

Goal: a beginner-friendly DIY kit with clear docs and hackable firmware.

Checkout also the blog about this project. ToGo-Lab Cloud link, actual internal link only. Suggestions welcome. Open an issue or email tgohle@togo-lab.io.

Repo layout

├── doc
│   ├── assets                                              // pictures, diagrams..
│   └── logs                                                // lab logs
├── firmware
│   ├── archive                                             // archive, derived from...
│   │   └── ATTINY45_2014_MorseThrowie
│   │       ├── ATTINY45_2014_MorseThrowie.ino
│   │       └── pitches.h
│   ├── include
│   ├── FireFly_MorseBlinker                                // arduino IDE file
│   └── src
├── hardware
│   ├── CAD                                                 // CAD files for mechanical work
│   │   └── ToGo-Lab_FireFly_MorseThrowie.dxf
│   └── KiCad                                               // KiCad project files
│       └── 0001-FireFly
│           ├── 0001-FireFly-backups
│           │   ├── 0001-FireFly-2025-09-07_180819.zip
│           │   └── 0001-FireFly-2025-09-07_181506.zip
│           ├── 0001-FireFly.kicad_pcb
│           ├── 0001-FireFly.kicad_prl
│           ├── 0001-FireFly.kicad_pro
│           └── 0001-FireFly.kicad_sch
├── License_-_CC_BY-NC_4.0.md
└── README.md

Hardware

MCU: ATtiny45/85 (internal RC clock, no crystal).
I/O: 1× LED + series resistor. Unused pins broken out to breadboard-style pads.
Burning Attiny: external ISP programmer via Arduino IDE; PDIP-8 ATtiny45/85 footprint.
Power: 3V DC (coin cell & & solar cell + supercapacitor with Schottky diodes to extend battery power).
Safety: low voltage only. Observe polarity.
PCB: hackable; access to unused ATtiny pins. (big pads for beginners, clear silks, LED polarity marks)

Firmware / Arduino IDE

Follow Documentation/ToGo-Lab_FireFly_ArduinoIDE_Program_Guide.md.
Board core: any stable ATtiny45/85 core.
Clock: internal. No fuse change required for first tests.
Programmer: USBasp / AVRISPmkII / Arduino-as-ISP.
Open the sketch in 0001_FireFly/Program/.

Assembly

Follow Documentation/ToGo-Lab_FireFly_Assembly_Guide.md.
First power-up: LED should blink test pattern. If not, recheck polarity and bridges.

Test / Bring-up

Visual check; no shorts.
Power at 3–5 V. Current < 10 mA idle.
Program firmware over ISP.
Verify Morse timing; adjust WPM in config.h if needed.
Optional: measure current.

BOM

Follow Documentation/ToGo-Lab_FireFly_BOM.csv as source of truth.

Files to fabricate

Gerbers and drill files from KiCad/fab/ (board house-ready).
Project file: 0001_FireFly/KiCad/ToGo-Lab_FireFly.kicad_pro.

Known constraints

Through-hole only. No reflow.
Minimal I/O to keep it beginner-friendly.
Low power is nice but optional; optimize after the basic release.

Roadmap (tech only)

v0.1-proto: breadboard + first PCB, single message, speed presets.
v1.0: build guide, BOM with alternates, pilot 10 units.
v1.1: docs polish, optional brightness setting, minor PCB tweaks.

Contributing

PRs and issues welcome. Keep it simple. Photos of your build you send me go in Documentation/gallery/ with a short caption and license notice.

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