This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Although the modern alarm clock is a wonderfully effective piece of mechanism, it is, to say the least, very abrupt in its manner. It seldom confines its efforts to the chamber of its owner, but spreads its disturbance all over the building. It is very easy for a person to arise early in the summer and no greater difficulty should be experienced in winter, if the bedroom is brightly lighted at the proper hour. To do this simply and automatically became the problem.
The first thought was to obtain one of those clock-actuated electric-light switches, such as the stores use, but this would not do, because it meant some unsightly wiring around the room. It was then remembered how, in the course of some experiments, an ordinary incandescent light was operated through a piece of No. 36 gauge wire without any sign of heating. If, then, a wire only 1/200 in. in diameter were of ample carrying capacity, surely a dollar watch would be sufficient to make the connection. Such being the case, the whole mechanism could readily be attached to the drop cord of a lamp directly above the socket, thus obviating any additional wiring. This all proved to be true, and the whole was made and attached in the course of a couple of hours.
While one might feel enthusiastic about this small and easily contrived affair, it is scarcely to be presumed that it would operate so effectively on one who had spent the larger part of the night tripping the "light fantastic," or in undue conviviality. An ordinary 16-cp. globe has thus far operated perfectly, and a 40-watt tungsten lamp would, if not too far away, surely awaken the hardest sleeper of sober habits.
The base of the mechanism is a small piece of 1/4-in. hard wood, upon which is fastened a small brass bracket, A, bent so as to hold the watch from slipping down. A small clip, B, was then arranged so as to grip the neck of the watch after its lower edge had been placed against A, and a small brad at either side prevented lateral movement. In this way the watch was held firmly, yet in a manner that would permit its being taken out instantly when necessary. The glass and minute hand were removed. The brass bolt from an exhausted dry cell was placed at C, so as to clamp a small copper washer to which was soldered a narrow strip of copper, D, about 1 1/6 in. wide and cut from a leaf of an old dynamo brush. This strip is arranged so as to wipe the hour hand as it travels past, but being so thin, it has no appreciable effect on the time keeping. As illustrated, the device is set for six o'clock, but by loosening the nut C an hour's adjustment either way may be had. It is a very simple matter, however, to arrange the device so it will operate at any hour. In connecting up, one end of the drop cord is removed from the socket and attached to A, which throws the current through the watch. thence along the hand and down D to C, from where it is carried by a short piece of wire to the socket again. As there are so many circuits through the watch, the small current required for one light does not affect it in any way. Thus far, no trouble has been experienced in making this delicate connection with 110 volts, but if any should develop, the contacts may be tipped with the small pieces of platinum taken from a burned-out globe.
The meat of a white English walnut may be easily removed by heating the nut in an oven or on top of a stove, then using a knife to pry the shell open.
possible to make it. The compartment must not be too wide, for the resulting small width of the front part of the drawer might then arouse suspicion. On the lower side of the secret compartment a strip of wood, A, should be attached with a screw, as shown in Fig. 1, allowing sufficient looseness so the strip may be turned end for end when necessary. With the strip set as shown, it will strike the front side B of the table when the drawer is pulled out, leaving the secret compartment still hidden. In order to expose this, it will be necessary to turn the strip, as shown in Fig. 2, when the drawer can be pulled out to its full length.
It being necessary that the strip A be as long as the secret compartment is wide, to fully expose this, there may be cases where the drawer is not wide enough to allow the strip A to turn around. In that case the strip can be hinged to the back of the drawer as shown in Fig. 3. When it is hanging down, as shown by the dotted outline, the drawer may be pulled out to its full extent. When it is desired to lock the secret compartment, the hinged strip must be swung up in position, and fastened. An ordinary thumbscrew or eye can be used which, by a turn or two, will either release it or fasten it in place. - Contributed by Paul Durst, Detroit, Mich.