Análisis de datos Colegio 3

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Figure 6-22 _{Waiting silently for the right moment}

Project 26—Give Us a Sign!

The next time you are sitting around a candle-lit room in dark robes with your pals trying to conjure up spirits from the nether world, make them think you have really made contact using this funny prank. This remote-controlled mechanical lever system is really a multi-purpose device for secretly moving objects, knocking on walls, flipping on and off lights, or triggering other mechanical devices. With the ability to move four or more levers

covertly, each capable of pulling a few pounds, there is no end to the ways you can creep out your friends in your haunted house or room. In this project, I will use the device to prove that I have made contact with ghostly spirits at a séance by calling out “give us a sign,” and receiving a few knocks on the walls just as the lights mysteriously go out all by

themselves. Of course, all this magic happens as I secretly move the joystick hiding under my chair or

on the floor while nobody is looking, which activates two of the servos I have on my four-channel receiver. The same commonly available RC servo and

transmitter set used earlier in this chapter are at work again, but this time as levers that pull and push to create a mechanical reaction on some other device. Shown in Figure 6-23 is the simple method of heat shrinking a long bolt to one of the plastic servo plates that come with the servo motors.

The bolt in the left of the photo has been heat shrinked to one of the servo plates and carries a metal weight at the end so it can knock against walls or wooden objects as the servo is activated slightly. An effective wall or door knocker is made using a 4- or 5-inch long bolt with a large nut or marble tapped to the end as a weight that will strike the surface. The servo only needs about 1_⁄

4inch of

travel in order to make an effective knock, so there is not much servo noise or lag time as you activate the joystick. My setup is currently using only two of the six available RC receiver channels, one to knock on the wall, and the other to pull down on the light switch, but I could easily add more servos as I come up with haunting ideas to freak people out. As shown in Figure 6-24, the dial servos, RC receiver and battery pack are simply tie-wrapped to a small aluminum plate (box lid), which can be tacked to a wall under a light switch out of view.

The flipping of the light switch using a hook and thread is pretty crude, but it does allow instant and

easy installation just about anywhere by simply tacking the unit to a wall. The servo can also be made to turn on a light dimmer by connecting the shaft to the dimmer knob, but this would be easy to spot if the light switch was in full view of your guests. Clear fishing line or light-colored thread hides very well, but in order to make a good photo, I used dark thread for my photo of the light switch hook shown in Figure 6-25. The thread is set tight while the bolt connected to the servo is at 90 degrees to the wall so that it will pull down on the light switch as soon as it is moved down in the same direction. It may take a bit of tweaking to get the right thread tension, but this is easily done by wrapping the thread around the bolt to make it tighter, or by repositioning the device on the wall.

The device is shown held to the wall by two thumb tacks in Figure 6-26. Placing the device as close to the floor as possible will help keep it out of view and, if needed, a cover that looks like a wastepaper basket or some other object that does not look out of place can be used. The RC receiver has a very long range, so no antenna will be needed on the receiver, and the remote control antenna can be collapsed all the way down without any problem. With a little ambient noise or music in the room, the servo noises will probably not be noticeable as the knocker or light switcher is activated, but if you think they may be too loud, then install a noise

Project 26—Give Us a Sign

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Figure 6-23 Heat-shrink mounted bolts

Figure 6-24 Everything is mounted on to an aluminum plate

baffle made out of cardboard and tissue paper over the servos to keep them silent.

Well, there you go, now you have a multipurpose remote-controlled room haunting device ready to switch lights, knock on walls, yank pictures off the wall, move objects, drop objects or trigger other

evil contraptions. The remote control can be mounted under your chair using a bit of Velcro® tape for easy access or simply placed under a table so you can control the stick with your feet.

Because the action will take place on the other side of a room or at some other distant location, you

Project 26—Give Us a Sign

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Figure 6-25 The servo can now pull the light switch off

will not be the center of attention, so moving the joystick will be easy to do without being noticed. Using all six servo channels, you could rig up an

entire haunted house and have your paranoid guests running out the door as you awaken mysterious forces from the other side.