This was one of my first Arduino based projects and I used it to help myself learn more about communication protocols with a microcontroller. It originally started off as a simple blinking LED that could be enabled or disabled with a push button switch. I soon taught myself how to have two Arduinos communicate with one another over the "Wire" protocol which uses I2C to communicate between devices. This way I could have the LED connected to the slave Arduino, while the brightness and pattern controls were connected to a second master Arduino.

Once I got the basics down of wired communication, I wanted to make the device wireless and accomplished this using a 433 Mhz RF transmitter and receiver module with serial communication between the two devices. One issue I ran into with this design is that it was limited to one way communication, and I solved this by using a 2.4 Ghz transceiver, which was similar to the 433 Mhz module, but the required code for two way communication was a new challenge for me.

My final task for this project was to replace the master Arduino with something more common, such as an Android phone, and interface with the slave device using Bluetooth. This was where I started to think of the idea of using this device like a smart watch where I could send a command from an Android app, and control a small motor on the Arduino to give the user feedback to distinguish if they received a text message, email, or a missed call.