Nintendo Extension Ctrl Library

Late last year when I was putting the finishing touches on the McCree Hammershot project, I decided to use a Wii Nunchuk hooked up to an Arduino for the controller’s movement. Although I eventually got it working, I had to try a variety of libraries before I found one that would even read the data properly. Most of them were convoluted, bloated, or poorly documented. Even the library I eventually ended up using was designed for controlling motors with a Nunchuk, not for just reading control inputs.

It’s now many months later, and once again I’m looking to build at least two more projects using extension controllers. So I decided to fix all of these problems and just build my own library.

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Building a DIY Stream Deck (Mini Macro Keyboard)

I’ve been doing a little streaming on Twitch (hiya!), and a lot of streamers I follow have something called an Elgato Stream Deck. The Stream Deck is a small device with 15 buttons, each of which has its own customizable RGB icon. By configuring the bundled software, users can set button icons and macros to control your casting software, send messages in the stream chat, launch programs, and much much more.

Unfortunately the Stream Deck is out of my price range, at a whopping $149.99 retail.  Fortunately I think I can make something that replicates the basic functionality for a fraction of that price: what I’m calling a “Stream Cheap”.

Although I’m focusing on using this as a replacement for a Stream Deck, at heart this is really a custom macro keyboard. It could be used as a hotkey board for any program. I’m just using it for OBS and Twitch.

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OBS Studio Chat Hotkey Script

As a tie-in to my DIY Stream Deck, I wrote a Python script for OBS Studio that allows you to send messages to Twitch chat using OBS’s built-in hotkey system.

Scripting

The 21.0 update for OBS added support for Python and Lua scripting, using a new scripting console and an extension of the C API. In the words of the developers, scripting allows you to “quickly extend, add features, or automate the program without needing to build a native plugin module.”

Since my non-embedded C++ still needs some work, I decided to try writing this program as a Python script rather than a C++ plugin.

Setting Properties

Via the scripts window, the chat script has access to Qt GUI elements in OBS such as text boxes, lists, and buttons. The user can fill in these fields to customize the script without having to modify any configuration files. With the initial release of the script, these configuration options include:

  • Channel: the channel on Twitch to post messages in
  • User: the username of the user posting messages
  • Oauth: the access key required for authentication to Twitch servers
  • Messages: the custom list of messages that can be sent

These settings are stored with the rest of your OBS settings and are reloaded on startup. There are also two buttons on the bottom of the panel for testing authentication and test sending the first message in the list.

(Note: I wanted the test message button to use the user-selected message in the list, but that property doesn’t appear to be exposed by the API, at least not yet.)

Hotkey Hooking

Each message added to the message list gets its own custom hotkey that can be modified in the OBS settings window. These work like any other hotkey in the program and are saved with their message in the script settings.

The list of messages is extensible, and will add / remove hotkeys as list items are changed. Reordering the message list will also reorder how items appear in the OBS hotkey settings.

Talking to Twitch Chat

Aside from the OBS API functions, the real meat of the script is the code for communicating with Twitch chat itself. Twitch chat is just IRC, so I’m using Python 3’s built-in socket library to handle all of the networking.

After a hotkey has been pressed, the script will open a connection to the Twitch server, authenticate, and then send a message. With version 1.0, this connection is released after a short period to avoid overhead and let repeated messages through without re-authenticating. All messages are rate-limited to the global limit based on the system time, which prevents the user from accidentally receiving a temporary site-wide chat ban for spam.

Any network errors are raised as exceptions if a test button is pressed, but are suppressed if triggered from a hotkey message. This is to alert the user if there is a problem during setup, but otherwise hide issues to avoid interruptions during streaming.

Using the Script

If you’d like to use the script yourself, it’s quite easy. Download the script from GitHub or the OBS resource page and follow the instructions in the README. By far the most difficult part is getting the OBS scripting console to work. You will need to install Python and point OBS to the installation directory. If you load the script and no properties appear, the Python installation / link is not set up correctly.

The script is licensed under GPL v3; it’s free software, so you can use it, modify it, and distribute it so long as you abide by the license.

Although I think it’s obvious, I’ll stress here that this is a 3rd party plugin for OBS. I have no affiliation or endorsement as a developer from either Twitch or OBS.

Conclusion

This was a fun script to write, and it makes me want to see what else I could with OBS scripting / plugins in the future.

I may end up converting this to a C++ plugin at some point, to avoid users having to install and configure Python to use it. But that’s a project for another day.

DIY PC Footswitch Using a Sustain Pedal

A couple of years ago I picked up an inexpensive sustain pedal for an electric piano at a garage sale. The piano itself wasn’t much to look at, but the pedal intrigued me… it’s a basic on/off switch, but the pedal itself feels fairly robust and I thought it would be a handy switch to have around.

This past week I finally got around to doing something with it! I built a small box that converts the signal from the pedal into a keypress, allowing me to use this pedal as a foot-controlled hotkey for my PC.

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Relay Boxes for Controlling 120V Power with a Microcontroller

For one of my recent projects, I needed a way to control some lights powered by a 120V household wall socket. Rather than reverse-engineering some commercial “smart outlets” for the task, I decided to try and do this the old-fashioned way by embedding relays in electrical boxes.

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iRacing Plugin for Prismatik

I’ve been trying to teach myself a little Python, and here’s what I came up with for my first small project. Using their respective APIs, I’ve built a plugin for the Prismatik ambilight software that maps live data from the iRacing simulator. A video demonstrates the end result far better than I can explain it:

 


The plugin itself is open source and hosted on GitHub. Click here to download the latest version.

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