Categories
Fun Projects Raspberry Pi

64×64 LED Matrix + Doom

From the weekend hacks department: I now have DOOM running on my 64×64 matrix!

GitHub repo: https://github.com/twstokes/doom-matrix

Categories
Arduino Coding Fun iOS Projects

Flip Dots! The technical bits.

I first want to acknowledge that I did the thing that I try to never do: I showed off a snazzy project, left some hints here and there of how it worked, said I would follow up with full details… and never did. That’s lame.

I’ve had multiple people reach out for more info and I’m glad they did, since that’s pushed me to finally get some repos public and this belated follow-up written. Apologies!

To jump straight to it, I’ve published these two repos:

Hardware

Let’s first go over the hardware involved. The most important piece, of course, is the Alfa-Zeta XY5.

In my case, the 14×28 board was made up of two 7×28 panels connected together via RJ-11.

The panels are pricey, but they can be thought of as “hardware easy-mode”. Alfa-Zeta has done the hard job building the controller that drives the hardware and all we have to do is supply power and an RS-485 signal that abides by their protocol.

If you purchase a panel from them there are two important documents to request:

  1. The main manual that describes the specs, features, and things like the DIP switch settings.
  2. The protocol for sending commands to the controllers (which is really simple).

These can easily found by searching around, but if you own a panel the company should supply them. Most of the protocol can be deduced by looking at open source code.

Components

The 24V -> 5V converter isn’t necessary if you supply power to the MCU independently, say through a USB power adapter.

Connection overview

  • 24V DC goes to both panels
  • 24V DC goes to the step-down converter, 5V DC goes to the 5V input of the NodeMCU
  • NodeMCU is wired to the RS-485 to TTL converter
    • VCC -> 3.3v
    • Gnd -> Gnd
    • DE -> 3.3v pulled high because we're always transmitting
    • RE -> 3.3v pulled high because we're always transmitting
    • DI -> TX[x] x being 0 or higher depending on board
    • RO -> RX[x] most boards only have the main serial IO, but boards like the Mega have multiple
  • RS-485 -> Only one panel controller – not both

An Arduino Mega is driving the board in this photo.

Software

The MCU

See https://github.com/twstokes/flipdots for the code that runs on the MCU.

At the moment there isn’t much to it – you can either compile the firmware to run in a mode that writes data from UDP packets to the board, or you can draw “locally” using Adafruit GFX methods.

See the README in the repo above for more details.

iOS / iPadOS / macOS

See https://github.com/twstokes/flipdots-ios for the code that runs on these devices.

Semi-interestingly I utilized Adafruit GFX again, this time via swift-gfx-wrapper to draw to the board over UDP. It’s hacky and experimental, but that’s part of the fun.

See the README in the repo above for more details.

Categories
Apple Coding Fun Nerd Sniped Retro Computing

DOOM on the Apple Watch

I know this has been done, but I hadn’t done it, so it was my weekend nerd snipe. (no game audio)

This was a lot easier thanks to doomgeneric!

Basic breakdown

Since doomgeneric exposes the framebuffer, I throw that into an SKTexture and that gets added to a node in the SpriteKit scene, which is subclassed to override the update method to call doomgeneric_Tick(). Objective-C is used for interop between C and Swift, and fulfills most of the functions listed here. SwiftUI ultimately outputs the scene.

Very few tweaks needed to be made in doomgeneric itself.

They were basically:

  • Conditional compilation for a few calls that watchOS didn’t support (and we didn’t need).
  • Tweaking the 32-bit color bit offsets.
  • Handling a crash related to passing in arguments.
    • On watchOS we pass the absolute path of the WAD file in the main bundle to the engine.
  • Adjusting some SDL2 includes so headers could be found.

GitHub repo: https://github.com/twstokes/AppleGenericDoom

Categories
Commodore 64 Fun Retro Computing

My C64 Setup

I haven’t spent as much time on my Commodore 64 as my other retrocomputers (which can seem modern in comparison), but my explorations over time are trending towards older hardware. I can only assume that my final stop will be an abacus.

I have three C64s all passed down from my dad. One had been devoted to a home alarm system (of course we still have the schematics), but by the time I came around it was only used for playing half-working totally not bootlegged games.

A sampling of some favorite software from my childhood:

Retrocomputing plans

I hope to be able to fully restore at least one of these machines this year. The one pictured above powers on and is fully functional, but some flakiness at startup tells me that it’s overdue for a recap.

One not-so-smart thing I did when I unpacked all of this equipment was powering it up with the original C64 power supply. That’s a risky move and likely to damage the C64 with bad power, so I’ve since replaced it with a new modern one (see the parts list).

I’m not interested (nor do I have the space) to use these machines in the “pure way” with a CRT and 1541 drives, although I have both. Maybe down the road that would be fun, but for now I’m utilizing modern gadgets from the wonderful C64 aftermarket community.

Current parts list

Next steps and ideas

  • Restore one or more C64s by recapping / adding heatsinks
  • Fix my joysticks / get new ones
  • Play with the WiModem232 and connect to the Internet
  • Play with the user port breakout and connect it to an Arduino
Categories
Fun Retro Computing

Cool Retro Term

It may not be real, but it’s so much fun!

Categories
Fun iOS Projects

SpriteKit SnowFlakes

From the seasonal hacks department, here’s my toy app to make it snow on macOS. ❄️

https://github.com/twstokes/snowflakes

How it works:

When the app is told to make it snow it adds full-screen non-interactive windows on each display and inside those windows adds a SpriteKit view with a scene inside that contains emitters.

That’s basically it!

Categories
Fun

Happy Festivus!

For the rest of us.

Scrolling text on a flip dots display that says “happy festivus!”

Categories
AI Fun Projects

Do you hear what I hear?

Thanks to Whisper and this awesome port, the tree is responding to spoken words. 🗣🎄

Since the tree itself only has a low-powered MCU, we need another machine to act as a listener.

The architecture is:

  1. A machine in my office runs the Whisper model and listens for words.
  2. If certain keywords are found it finds a corresponding command to run (e.g. do a theater chase sequence in a green color).
  3. It sends that command to the tree over the network.

For now I’m running it from iOS and macOS, so I wrote the current implementation in Swift. The code is currently still in “hack” status, but working well!

Now it’s time to test it when talking to coworkers at Automattic.

Categories
Fun Retro Computing

Windows 3.11 in QEMU

Thanks to this repo you can fire up Windows 3.11 painlessly and even connect to the Internet! Lots of goodies are already installed so it’s a fun virtual trip.

To get it going on my Mac all I had to do was:

  1. brew install qemu
  2. Run qemu-system-i386 -nic user,ipv6=off,model=ne2k_pci -device sb16 -vga cirrus -snapshot -no-shutdown hda.img

There were some graphical glitches (restarting or dropping down into DOS and back helps) and it crashes when running Netscape, but Microsoft Bob seemed to work fine!

After configuring the network’s gateway and DNS servers, I had to visit one of my favorite test sites for old browsers:

The Dole / Kemp ’96 website is still alive and kickin’.
Categories
Arduino Fun iOS SwiftUI

NeoPixel tree progress

This weekend the NeoPixel tree got many much-needed updates!

Though I have more ideas to implement, the basics of what I wanted to do are complete, like sending commands remotely.

What we can currently do:

  • Set the brightness
  • Change the color
  • Turn the pixels off
  • Run some built-in sequences, like a nice rainbow
  • Set repeating color patterns
  • Set individual pixels

I also threw together a really quick iOS app to set the color with SwiftUI’s built-in ColorPicker view. Thanks to the Rover project (another one that’s been neglected), I had some UDP client code I could borrow to speed up development.

Changing the color of the tree with a SwiftUI ColorPicker view.