LED Sunrise Alarm Clock with Customizable Song Alarm


Step 2: Power Supply Circuit, LED Driver Circuit, and Wiring

Picture of Power Supply Circuit, LED Driver Circuit, and Wiring
Current Source.jpg
Clock Pins Connected.jpg
Notch in Clock.jpg
Alarm Wiring.jpg
Threading Underneath Ribbon.jpg
Wires Thread.jpg
Wires Thread 2.jpg
Power Supply Circuit

If I were to hook the microcontroller straight up to the Vcc of the clock, I would blow it up (well not really, but render it useless). I needed to condition the voltage and bring it down to 5v. I used a simple regulator circuit that uses just two capacitors and a 5v regulator. I went to the schools lab and located a 5v regulator in the trash pile. I hooked up the circuit and tested it out. It provided a nice and steady 4.99v.

LED Driver Circuit

Since the ATMega168 can only deliver about 16mA of current to each of its digital outputs, a current regulator is needed to power the LEDs. I found this circuit on the Arduino help forums and it seems like a fairly common and simple circuit. To direct the light of the LEDs, I decided to use a reflector from a flashlight. The flashlight I bought had three holes for three LEDs. I decided to grind them bigger and put four in each hole, thus explaining the way the circuit is drawn.


Once I figured out I could successfully use the clock's Vcc and the the alarm output, I decided to solder up some thin wires and thread them out through a hole in the side. I also had the idea to add a loop in my microcontroller program to play a song instead of the original alarm. I soldered two longer wires to the piezoelectric speaker and threaded those out the side as well. I used some wire clippers to cut out a small notch in the top half of the clock and screwed everything back together.
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