Raspberry Pi + Ruby (WiringPi) + LED
require 'wiringpi'
# run: rvmsudo ruby blink.rb
ledPin = 5
io = WiringPi::GPIO.new
io.mode(ledPin, OUTPUT)
loop do
io.write(ledPin, HIGH)
sleep(0.5)
io.write(ledPin, LOW)
sleep(0.5)
end