Wolfram Omega is an attempt to voice control the Wolfram|Alpha API. It sort of works, sometimes. It is Mac only. Deps: nokogiri (nokogiri.org), speech2text (https://github.com/taf2/speech2text), coreaudio (https://github.com/nagachika/ruby-coreaudio)

wolfram_omega.rb

require 'coreaudio'
require 'speech'
require 'nokogiri'
require 'open-uri'
require 'uri'
require 'tempfile'

Signal.trap("INT") do
  puts "Terminating..."
  buf.stop
  $stdout.puts "done."
  exit
end

ApiKey = '' #Put thy Wolfram|Alpha API key here.

$dev = CoreAudio.default_input_device
buf = $dev.input_buffer(1024)

def speak(text)
   IO.popen(["say"], "w") {|pipe| pipe.puts text}
end

def wolfram_alpha(question)
  doc = Nokogiri::XML(
    open(
      URI.escape(
        "http://api.wolframalpha.com/v2/query?appid=#{ApiKey}&input=#{question}&format=plaintext"
      )
    )
  )
  answer = doc.xpath "/queryresult/pod[@primary]"
  return answer.text.strip
end

current_file = ""

def start_recording
  # create temp file, begin recording sound.
  $current_file = Tempfile.new ['wolfram_omega', '.wav']
  
  $dev = CoreAudio.default_input_device
  
  $wav = CoreAudio::AudioFile.new($current_file.path, :write, :format => :wav,
                                 :rate => $dev.nominal_rate,
                                 :channels => $dev.input_stream.channels)  
end

def stop_recording
  # stop recording, dictate text, and speak answer.  
  $wav.close
  $current_file.close
  
  audio = Speech::AudioToText.new $current_file.path
  begin
    question = audio.to_text["hypotheses"][0][0] 
  rescue NoMethodError => e
       puts "No hypothesis..."
  end
      
  answer = wolfram_alpha question
  speak answer  
end

buf.start;

puts "^C to quit."
$stdout.flush

writing = false

loop do
  w = buf.read(4096)
  
  if writing
    $wav.write w
  end
  
  if w.rms > 400 && writing == false
    puts "Got question!"
    
    writing = true
    
    start_recording  
  elsif w.rms < 400 && writing == true
    writing = false
    
    stop_recording
  end
end