A while ago, I stumbled over a component called DFPlayer. It's a tiny component that allows to play mp3 from an micro SD card (for less that 10€!).

http://www.dfrobot.com/wiki/index.php/DFPlayer_Min...

Since I was sick of using my smartphone as an alarm clock just to have music to wake me, I decided to build an alarm clock with it.

Step 1: Required Components

1x DFPlayer (7,80 Euro)
1x Arduino UNI (20 Euro)
1x LCD Display (20x4, ~10 Euro)
4x 10k Resistors
2x 1k Resistors
1x 10k Poti
1x Rotary Encoder (1,50 Euro)
3x Push Buttons
1x Visaton FRS 8 Speaker (10 Euro)
Some cables for wiring and circuit board(s)

Additionally you may want an adjusting knob for the rotary encoder, a frame for the display and a case. My father made an oak case for me which looks pretty nice.

Step 2: Arduino Setup

Connect the Arduino via USB to your PC.
Make sure that you have the Arduino IDE installed.
Download the .ino the attached .ino file and the additional 3x zip files
The Arduino IDE provides a wizard where can select the zip file to include a new library.(Sketch -> Include Libraries ...): Install all 3x libraries using this wizard

The .ino file should compile now and you can upload it to your arduino.

Step 3: Wire Components

Before soldering everything together, I recommend using a breadboard to prototype everything.

I created a fritzing image to help with that. You should check the correct wiring of the DFPlayer by using the provided link. You can find a description of the DFPlayer's pins there, but assuming the 5V+ pin is in the upper left corner, the wiring should match as shown on the picture.

Step 4: Build Everything Into the Case

The step varies depending on what case you have chosen to use. I've added some pictures here to show the steps I've done to wire everything into my oak case. I decided to build smaller circuits on smaller circuit boards to have checkpoints where I can verify that everything is still working.