Dan Morrill decided to take the Garduino system that he built a step further, and created a remote control that runs on an Android phone and talks to the Arduino over Bluetooth:

In practice, it takes your “Serial.print” output from an Arduino program and makes it available over Bluetooth to a PC….. or a phone. Android, meanwhile, added an API for Bluetooth RFCOMM in version 2.0. My wife got me a BlueSMiRF for my birthday, and it was off to the races.

I rewrote the Arduino code into a simple finite state machine, and added the ability to accept commands over serial. It’s a very simple project, so there are only 2 commands: reset, and set current time. I encountered some interesting open-source related issues in doing this, but that’s another post.

I then wrote a spiffy little Android app that pairs up to the BlueSMiRF, reads the state dumped from the Arduino every 3 seconds, and then makes a pretty little Android UI. It shows me a Sun, Moon, or Clock depending on which state the Arduino is in (daytime, nighttime, or waiting for clock data), and reports the other status fields like light intensity and status.

Garduino Redux

Source code for Arduinos and Android devices