omc345 notes

Yo, my guy, look. Most people play Conway’s Game of Life on a boring browser tab. Some absolute madman (lcamtuf) decided to spend a "college savings" amount of money to build a 17x17 physical grid of clicky, glowing buttons to do the same thing. 🚀

It’s tactile, it's expensive, and it’s a masterclass in "because I can." Let’s break down how this beast actually works.

1️⃣ WHY? (The Pain vs. The Gain)

Look, computers are great, but they lack soul. 💀

The Problem: On a screen, the Game of Life is just moving pixels. There’s no "thunk," no "click," and no physical interaction. You're just a bystander.
The Solution: This project turns a math concept into Interactive Art.
- Tactility: You press a physical switch, it lights up.
- The "Ohhh" Moment: Instead of clicking a mouse, you're "painting" with light and mechanical switches. It’s the difference between driving a Tesla and a classic stick-shift Mustang.

2️⃣ THE BIG PICTURE 🗺️

Before we talk chips and wires, understand the layout. We have a 17x17 grid (289 total switches). Each switch has a built-in LED.

THE BRAIN 🧠

MCU (Microcontroller): An AVR128DA64. It’s the boss. It calculates the rules and decides who lives or dies.

THE GRID ⚡

Input: The 289 switches.
Output: The 289 LEDs inside those switches.

3️⃣ THE MECHANICS ⚙️

How do you control 289 things when your chip doesn't have 289 pins? You use Matrix Scanning. 🧠⚡

How the Display/Input Works:

Row Scanning: The system doesn't turn everything on at once. It turns on Row 1, checks the buttons/lights the LEDs, then turns it off. Then Row 2, and so on.
LED Pumping:
- Because a row is only "on" for 1/17th of the time, it would look dim.
- The Hack: They blast the LEDs with way more current (150mA) than they’re rated for. Since it's only for a split second, they don't melt. 💥✅
Circuit Protection:
- MOSFETs: Small transistors acting like high-speed gates to handle the heavy current the MCU can't touch.
- Watchdog Timer: If the code freezes while an LED is "blasting," the LED would burn out. The Watchdog kills the power and reboots the system if it hangs for more than 15ms. Safety first, fam. 🛑

The Hardware Stack:

4️⃣ THE RULES OF THE GAME (Logic) 🧬

If you've forgotten how Conway's Game works, it's basically a "SimCity" for cells:

Underpopulation: Any live cell with < 2 neighbors dies. (Lonely 😢)
Overpopulation: Any live cell with > 3 neighbors dies. (Crowded 😵‍💫)
Survival: Any live cell with 2 or 3 neighbors lives on. (Just right ✅)
Reproduction: Any dead cell with exactly 3 neighbors becomes alive. (Digital magic ✨)

5️⃣ ASCII FLOW: How one "Step" happens

USER TURNS KNOB ──► ADC SENSES VOLTAGE ──► SETS TICK RATE
      │                                       │
      ▼                                       ▼
SCAN SWITCHES ◄───────────────────────── MCU CALCULATES
(Press to Toggle)                        NEXT GENERATION
      │                                       │
      └──────────────────┬────────────────────┘
                         ▼
                BLACKOUT WINDOW (ms)
           (Update state while LEDs are OFF)
                         │
                         ▼
                REFRESH LED MATRIX
             (Row by Row, Super Fast)

⚡ LOCK IT IN (TL;DR)

It's Expensive: The switches alone cost nearly $900. It's a flex. 💀
It's Fast: The MCU scans the grid so fast your eyes think it’s a constant image.
It's Safe: Hardware failsafes (Watchdogs) prevent the high-current LEDs from turning into tiny lightbulbs that explode.
It’s Analog-ish: Using a physical knob for speed and physical buttons for "drawing" makes a 50-year-old math game feel brand new.

Yo, final thought: If you want to build this, start saving your lunch money. Those NKK switches don't play. 😂🔥