Alarm Clock of the Short Now
or
A beginner’s PIC project.

I am unemployed at the moment, but I’m very busy. I tend to work late nights and wander over to bed when I run completely out of steam. The problem is that this happens at a different time every day. I end up being too lazy and stupid to re-set the alarm clock, so I don’t bother. I oversleep. Recently I realized that I need a special alarm clock that instead of going off at a particular time goes off after a set duration. Like an egg timer, but grand!.

So, I made one, and I realized that it would be a great beginner’s project. I could have added things like a snooze feature or a variable time span, but I opted to keep it simple. If you want something much more complicated, you can try my MP3 player project. Or add some crazy stuff to this one. This is also easily adapted to other timing and control projects.

Operation:

To use the clock, flip the switch to “on� and get in bed. The LED will blink once each second to let you know it’s working. Go to sleep. When the alarm goes off get up and flip the switch to “off�.

It’s a new day!

Construction:

The most fun part is the thing that actually makes the noise. I used a motor from a small toy and a strip of aluminium. I attached a small bit of wood to the shaft of the motor and glued the motor to the strip of metal so that the bit of wood smacks into it. It makes a really remarkably annoying sound. I also tried placing the motor in an old glass jar. You could try a cowbell, or a cymbal, or anything really.

Not much else to say here, other than that you should try things out on a breadboard first, and that if it doesn’t work, 90% chance that it’s a soldering mistake. Oh, by the way: I tested the code. It works. Really.

Code:

Here’s the C code, the schematic and the
hex file. The C is the source code, which you can modify to your heart’s content, the hex file is what the compiler makes from the C code.

Questions? I can be reached here: raphael@walrus.com

A nice cosy view of the innards. The glob on the right is the LED, the hole with the red and blue wire is the switch ( I replaced it later on with a three-wire one). On the right of the circuit board is an ICSP header. You don’t need that unless you want to program the chip while it’s still in the board. In fact, if you haven’t heard of ICSP yet, don’t worry about it.

Testing the motor with the little bit of wood. It’s actually loud enough to wake me just as it is pictured here.

More innards. I am using 4 AA cells here. You could probably get away with using just two or three if space is a problem. If the motor seems weak, use more voltage (up to 5.5V).
A “wall wart� would work also, but you would need to add a voltage regulator.