Comment by the_third_wave

Just make sure to either set the thing to not go to sleep while connected to a power supply in the developer settings, get a wake lock for your specific application or use another app to keep the device awake. Android phones make for versatile sensor-rich platforms for monitoring/media/etc. applications. They come with their own wifi hotspots, 3/4G communications, several cameras, microphones, motion sensors, compass, gyroscope, light sensors, proximity sensors, magnetic sensors and more. They even have their own built-in UPS so... get hackin'.