PiXel (Pi Pixel)

Make NeoPixels react to Twitter trends

Reacting to live tweets

Reacting to a special hashtag

Overview

• PiXel runs on a Raspberry Pi, and triggers LED animations based on current Twitter trends.
• For every tweet in the last 5 seconds that matches one of the user supplied keywords, PiXel flashes a random LED on the strip.
• If nearly the same number of tweets as pixels are found, then a random special animation is triggered
• If barely any tweets are found, then the pixels glow dimly
• If a user supplied special keyword or author is found, then a specific special animation is triggered.
• A toggle button can be added to cycle the array between the Standby/OFF, Twitter, and Glow states

Hardware Requirements

• Raspberry Pi (2x/3x) with Latest Raspbian
• Raspberry Pi Power Supply (2+ Amps)
• WS281X LED Strip (NeoPixel or clone)
• 5v Power Supply - (0.06 * Number of Pixels) Amps
• Logic Level Conversion (see Adafruit Guide to Using NeoPixels with Raspberry Pi for more details on wiring)
• (Optional) Toggle button (for controlling modes)

Alternatively, Order and Assemble a NeoPixel Shield

Dependencies

RPi.GPIO

• Should be preinstalled in newer Raspbian

rpi_ws281x

• Follow library installation instructions

Python Twitter

• Install with $ pip install python-twitter or follow the link and install manually.

Setup

• Follow Adafruit Guide to Using NeoPixels with Raspberry Pi to set up WS281X Strip. Connect to [GPIO18, GND]
• (Optional): Connect Toggle button to [GPIO24, GND] for Mode Toggle
• Install Raspbian & Dependencies on Raspberry Pi (see raspbian installation guide for more details)
• Set up Twitter Dev account and register for API keys. See python-twitter docs for information about setting up API Keys
• Configure conf.py with API keys, LED colors, and correct GPIO pins
• run main.py with super user permissions, i.e. sudo python $PIXEL_PATH/PiXel/main.py OR to run at startup (hack-y)

  ## Enable PiXel @ start
  if ! ps ax | grep -v grep | grep python > /dev/null; then
      screen -d -m -S PiXel bash -c 'cd $PIXEL_PATH/PiXel/ && sudo python main.py'
  fi

Queries

PiXel uses 3 query types. For information about formatting, see Twitter Search API documentation. All three queries are included in the q field of a Twitter Search call.

• QUERY_KEYWORDS: These keywords trigger a single flash.
• QUERY_SPECIALS: These keywords trigger a special animation.
• QUERY_FROM_USERS: If a tweet was written by this user a special animation is triggered.

Author

Ian McLinden, 2018

• [ ] done