Taking Apart a Digital Alarm Clock

An Ign'ant Fool's Perspective


The following is a fairly straightforward account of the disassembly of a cheap Cosmo brand Model E571-03W Digital LED Alarm Clock. I found it in a box of disused telephone cords. It is small and shiny and black and not of very good quality. It suffered from a faulty "hour" button. Always one for an adventure, I grabbed a set of screwdrivers and set to work taking it apart and fiddling with its innards.

IANAW, and all descriptions of the little electronical bits are thus imprecise and visual.

The Case

The outer case of the thing, as previous mentioned, is shiny and black. It has buttons on top for setting the time and alarm. It clearly had to go. It was keeping me from the interesting bits. After reading the botton of it for a bit of information (it was made in 1996), I unscrewed it with a small Philips screwdriwer.

With the case off, the clock suddenly looks very different.


Starting from the wall inwards, there is a plug followed by a power cord, taking household current to the little power supply. It looks like a stack of two blue, squat, rounded recatangular prisms stcked on one another, sandwiched betwwen two bits of translucent white plastic, and the whole thing is surrounded by a copper-colored metal band. It's very nifty-looking. The black power cord goes in one end, and two red and one black wires come out of it, leading to the rest of the clock.

It's also worth noting that there is a red/black pair of wires attached to a 9 volt battery used for backup in case of power loss. Those wires also tie into ...

The Central Circuitboard/LED/Button Panel Thingy

This is obviously the real guts of the machine. Here lie three interconnected circuit boards, each very different from its fellow. I shall begin with the central one.

This little thing looks like most circuit boards that you've seen. On the green side with the shiny metal bit, there are attached five black and red wires from the power sources. The brown side of the little chip of plastic, silicon, and metal has lots of interesting things on it. Transistors, resistors, and other such things decorate this rather typical little wonder of civilisation.

The next one houses the buttons. It looks much like the previously described board, and is attached to it by a little black ribbon cable. It has several little holes in it, and the brown side is blank save for one wire. The green side is adorned with compressible metal dots and little rectangles of metal that were covered with switches. It's wider but not as long as its parent.

The final central bit is the glowing numbers, the bright red LED. It too is mounted on a circuit board, and is attached by a row of thin, stiff wires to a strip of white plactic on the central board's edge. I am convinced that it can be used for something fun. Please /msg me with any ideas.

The Bit That Makes Noise

This, perhaps the most useful, or at least entertaining piece of the clock, is just a thin metal disc. It has a pair of wires hooking into the central board. In addition to the great fun that can be had with a noisemaker and a battery, other things might be able to be hooked into the parts that this is attached to. Who knows?


A companion w/u would fit beautifully here, one with a more learned viewpoint.

Blackpawn suggests sewing the LED into a t-shirt and having it display whatever I want. He went so far as to suggest "X days since I last got laid" display, but I think that a sideways 8 would look funny.