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

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.
<p>this is really cool, I need to tweak <a href="http://www.instructables.com/id/13W-LED-wake-up-light-my-version/" rel="nofollow">my setup</a> to something similar asap..</p>
Can you explain to me where you found the ground and the alarm pins?<br /> <br /> I was thinking i could just solder in some LEDs to them and when the alarm goes off the LEDs turn on<br />
&nbsp;Is there a way I could get the larger version of both wiring diagrams?
I&nbsp;see what you're saying now. I looked but I'm not sure where the files are. I&nbsp;built this when I&nbsp;was co-oping so the files are probably on the computer at work. The big drawing is basically all those little drawings put together though.<br />
Hi, Nice work. What would happen if i used a different speaker instead of a pezio? Ben
Not entirely sure but I think you'd need to use a amplifier because the voltage coming from the chip would be too small. If you buy an alarm clock, it'll come with one.
well...actually i use to be really obsessed with electronics....now i am more into food..muahahaha. i just advertise ur project to my electronic crazy friends. They will soon check ur project out. Looking forward to see more of ur creations.
Ha, food is another one of my favorite hobbies. Thanks for showing your friends! I got a few more projects in mind... Just gotta get around to building them and documenting them.
nice one. thumbs up
Thanks! I'm kinda confused about the lack of comments. After I post a project I usually have nice discussions about it! but not for this one :/
Nice work. In my setup, the LEDs alone aren't enough to wake us, which I why I have incandescents in the loop too.
Thanks!! Yeah, I can see how they may not be bright enough. I was worried about that too but then I thought about a nice alarm that would be more pleasant, even if the LEDs didn't fully wake you. I liked your setup, I was just afraid of breaking screwing something up and breaking the $60 clock :/

About This Instructable