Family mruby Documentation¶

What is Family mruby?¶

Family mruby is a small computer that boots straight into a Ruby programming environment.

Plug in a keyboard and a mouse, connect a screen, and you get a desktop, a launcher, an editor, and a shell — all running on a single microcontroller. Everything you write runs on the same machine you write it on. There is no PC toolchain in the loop, no cross compiler, no flashing cycle: press F5 in the editor and your program starts.

The editor with flappy.rb open, and the game it just started running in the window next to it

The editor and the app it just started, side by side on the device

It is built on PicoRuby and ships with its own multitasking OS, so several apps can run side by side, each in its own isolated heap.

Two machines, one system¶

Version 2.0 runs on two very different pieces of hardware. The same Ruby app runs on both.

	Modern	Retro
Hardware	M5Stack Tab5	narya-board (dedicated board)
Main chip	ESP32-P4 (dual-core RISC-V) + ESP32-C6	ESP32-S3 + ESP32-WROVER
Screen	Built-in 1280x720 IPS panel, MIPI-DSI	NTSC composite out, to a CRT or a capture device
Framebuffer	426 x 240, scaled 3x onto the panel	320 x 240
Sound	Built-in speaker, headphone jack	3.5 mm line out
Input	USB keyboard & mouse, capacitive touch, Tab5 Keyboard	USB keyboard & mouse
Network	Wi-Fi / BLE via the on-board ESP32-C6	Wi-Fi / BLE on the ESP32-S3
Extras	Browser remote desktop over Wi-Fi, GROVE port	RCA video, 2x GROVE, battery-backed RTC

Modern is the machine you build things on: it is self-contained, it has a screen in the lid, and you can drive its desktop from a browser on your PC over Wi-Fi.

Retro is the machine you play on: real NTSC composite video into a CRT, the 256-colour picture and the NES-style 4-channel sound chip that goes with it.

Not sure which to read? See Choose your hardware.

Retro on the left, Modern on the right, both showing the same shell

Retro (narya-board, into a monitor) and Modern (M5Stack Tab5) — the same shell on both

What's new in 2.0¶

A second machine. Family mruby now runs on the M5Stack Tab5 — one ESP32-P4 doing graphics, sound, input and the OS by itself, with capacitive touch, the Tab5 Keyboard, Japanese fonts, and the built-in speaker. → Modern (M5Stack Tab5)

Your screen, in a browser. Modern serves its own desktop over Wi-Fi. Open the device's address on your PC and you can watch it and drive it with your PC's keyboard and mouse. → Remote Desktop

Ruby on the network. A CRuby-shaped networking API — Net::HTTP, WebSocket and TLS — so an app can talk to the internet in a few lines. Works on both machines. → Network

Music out. A MIDI layer that plays through the built-in sound chip or out of the GROVE port to an external synth, an SMF (standard MIDI file) player, and MML for Ruby apps. → MIDI

Two more languages. .bas files run on FMRuby BASIC, a Family BASIC-compatible interpreter with its own text screen and sprites. .py files run on an embedded MicroPython. Both launch as ordinary apps, next to the Ruby ones. → BASIC and MicroPython

Debugging that reaches the device. Set breakpoints from VS Code over TCP or BLE, or use the debugger built into the on-device editor. → Debugging

A faster, quieter system. The kernel is now ahead-of-time compiled to native code, which cut input latency; the desktop boot dropped from about 20 seconds to about 6; and the desktop no longer allocates in its steady state, so it stops stealing time from the app you are actually running.

Demo Video¶

Getting the hardware¶

Modern runs on a stock M5Stack Tab5 — no modification, no soldering. Flash it from your browser and it boots.

Retro needs the narya-board, available on BOOTH. The schematics, Gerber data and BOM are all public, so you can also build a compatible board yourself.

Where to go next¶

Choose your hardware — the differences that matter
Modern (M5Stack Tab5) — from an unboxed Tab5 to the desktop
Setup (Retro) — cabling and first boot on the narya-board
Hello World — your first app
Connecting to Wi-Fi — remote desktop and networking
Simulator — run the whole system on Linux, no hardware needed
API Reference — what your app can call

Repositories¶

Development Background¶

Long ago, BASIC was often the first programming language that children encountered. Despite its limitations, there were products like Family BASIC, which allowed BASIC programming not only on PCs but also on platforms such as the MSX or the Famicom (NES). Many programmers discovered the joy of programming through these environments.

Today, development environments for most programming languages are freely available and easily installable on PCs. However, because so much is possible, beginners often don't know where to start. Even reaching the point where you can make something slightly beyond "Hello World," such as a simple game, can require a surprisingly high setup cost.

Family mruby was born from the desire to create an environment where you can build small games and other applications using a scripting language on a single microcontroller -- bringing back the joy of simple, immediate programming.