Sleep As Android can do this same thing. It uses your microphone/accelerometer to sense motion and estimate when you're entering REM sleep. It's not as advanced as the more complicated set up here, but anecdotally I can say it works fairly well. You can set it to play a trigger phrase when you enter REM sleep to help train lucid dreaming. I've never done it though because they default trigger phrase included is downright creepy sounding. It's some echo-y modulated voice that goes "You are dreaming-ing-ing-ing...."

I was expecting the article to be an actual dream control device and not just a device that helps you control your own dreams. Kind of misleading.