The Amazing Magic Flashlight

Amaze and frustrate your friends with The Amazing Magic Flashlight. This very simple project should take you no more than 30 minutes to construct. When completed you will have a flashlight that no matter how hard anyone tries, the flashlight can not be turned on or off. However, you, with the secret, can turn it on or off at will. The "magic" is a magnetic reed switch wired in series with the flashlight's on/off switch. When a magnet is brought into proximity of the flashlight case, the magnetic reed switch will close and the light will turn on!

This video shows The Amazing Magic Flashlight in action. A concealed magnet (taped to the bottom of my hand) is brought close and then pulled away from the flashlight causing the light to turn on and off. In the last step of this instructable is another video that shows how the push button switch appears to have no effect but when switched on and a magnet is near, the light turns on and off.

Step 1: Parts List

All you need to construct The Amazing Magic Flashlight is:

1. A "normally open" magnetic reed switch.  I obtained mine from Jameco Electronics. The switches are part number 171872 and cost $0.85 each. As you can see in the images, these switches are made of glass, so I recommend you buy several just in case you break one.
2. 24" of flexible wire. I used speaker wire but you can use whatever you have handy as long as the wire is very flexible.
3. Magnets.
4. Electrical Tape.
5. 6V Flashlight/Lantern.

You'll need the following tools:

1. Soldering iron and solder.
2. Wire cutters.
3. Wire stripper.

Step 2: Modify the Flashlight Wiring

The first thing you have to do is modify the flashlight wiring.

1. Unscrew the top of the flashlight and you'll see the wires from going from the battery to the switch and from the switch to the lamp assembly as shown in the first image.
2. Cut the wire that connects the switch to the lamp assembly as shown in the second, third, and fourth images.

Step 3: Prepare the Extension Wires

Now prepare the extension wires. These extension wires will connect the wires in the flashlight to the magnetic reed switch:

1. Cut two 12" lengths of the flexible wire and strip a small amount of insulation off the ends.
2. Solder one end of one of the wires to the wire coming from the switch in the flashlight as shown in the first image.
3. Wrap a small piece of electrical tape around the soldered wires, as shown in the second image, in order to provide insulation from the other wires and the battery terminals inside the flashlight.
4. Solder the end of the second piece of wire to the wire attached to the lamp as shown in the third image.
5. Wrap a small piece of electrical tape around this connection as shown in the fourth image.

You might think you could skip this step and just directly attach the magnetic reed switch to the wires in the flashlight and that would be a big mistake as I learned the hard way when I started to construct this project. When you screw the lamp assembly back onto the body of the flashlight, all the wires twist around inside the flashlight.  If the wires are stiff, they will put a lot of tension on the magnetic reed switch and it will shatter and break apart.  If you use long flexible wires as described, you won't have this problem!

Step 4: Prepare the Magnetic Reed Switch

Now prepare the magnetic reed switch as follows:

1. Solder the ends of the extension wires to the magnetic reed switch as shown in the first image.
2. Cut two small pieces of electrical tape and use them to insulate the exposed wire as shown in the second image.
3. Using electrical tape, attach the magnetic reed switch to the inside of the case near the top and near the handle. Placement of the magnetic reed switch is important - to make the magic happen you will need to bring the magnets close the spot where you've attached the switch. The ideal location would be right under the handle but for the flashlight I used, there wasn't room, so I placed the switch under the top near the handle.
4. Carefully tuck the wires into the flashlight and screw the lamp assembly onto the body of the lamp.

The completed wiring is depicted in the schematic in the fourth image.

Step 5: Voila!

Now you're ready to use The Amazing Magic Flashlight! The video below shows how to use it. Without the use of a magnet, no matter how many times someone pushes the button on the flashlight, it will not light. However, since you know the secret and have cleverly concealed a magnet in your hand, you can push the power button to the on position and the light will come on!

To make using The Amazing Magic Flashlight more impressive you could consider making a magnetic ring that you wear and use that to trigger the magnetic reed switch. You could attach a magnet to a ring (a neodymium magnet would work great), try to magnetize an iron ring, or buy a magnetic ring like the Wizard PK Ring.