How to Build a Laser

A laser is defined as an optical device which emits a beam of light radiation. Unlike light from other natural and artificial sources, a laser is monochromatic, meaning it only casts light of a very specific wavelength. If the wavelength were in the visible spectrum the laser would appear as a certain color. As lasers have been developed they've found uses besides the purely academic fields. They're commonly used to read the contents of CDs and DVDs. Extremely powerful lasers are used to cut through metals in heavy industry or etch patterns and designs into hard surfaces. Small and precise lasers are used in surgery to cut tissue and cauterize blood-flow. They also have military applications as range-finders and targeting devices. As a fun experiment and a cheap alternative to purchasing your own commercially produced laser, here is a guide to building your own laser.

Things You’ll Need:
Soldering Iron

Soldering Wire

Tweezers

100ohm POT

16X Laser Diode

Top of An Axis Module

Screwdriver

Triple A Battery Holder

2 Triple A Batteries

Power Switch

Cardboard Tube

Tape

Scissors

Sheathed Copper Wiring

Making A Laser
Step 1:
Take the positive and negative leads running from the Triple A Battery Holder and press them against the corresponding points on the switch. Press your soldering wire to the leads and melt the solder in place with the soldering iron. Set this aside.

Step 2:
Solder the 100ohm POT to the 16X Laser Diode. There will be three points on the back of the diode in a triangle pattern. The 100ohm POT will connect to the one top or outside point on the back of the diode. This will help regulate the flow of electricity through the diode to create an actual laser rather than a constant Light Emitting Diode.

Step 3:
Connect two lengths of copper wiring to the remaining contact points and solder them into place. The other ends of the wire should be soldered to the two remaining points on the back of the 16X Laser Diode.

Step 4:
There should be a screw on the side of the POT which alters the resistance it creates. use your screwdriver to set it to put out maximum resistance. Insert two Triple A Batteries into the holder and turn on the device.

Step 5:
Watch the diode and slowly lower the level of resistance on the POT. Stop when the diode is at its brightest. Turn off the device.

Step 6:
Slip the diode in the Top Half of The Axis Module. This Module looks a bit like the head of a flashlight. Essentially it is a metal cylinder containing a number of focusing lenses. The appropriate focusing of a laser is and always has been the most difficult part of building one and it's a little too sophisticated for someone without a degree in Physics, specializing in Optics, and in possession of a fully functional optical laboratory. So it's best to go with a store-bought lens.

Step 7:
Seat the diode inside the Module at a very specific distance from the lens. If the lens is far from the diode, you will create a harmless laser pointer. if the lens is right up against the diode you will create a laser capable of burning skin, setting paper alight, melting plastic, and charring wood. Decide which of the laser types you wish to create and apply a few pieces of solder to the back of the diode, where it touches against the inside of the Module, to hold the device in place.

Step 8:
Fit the whole device to slide down the inside of a cardboard tube such as you would get from a paper towel roll or toilet paper. With the front of the Module peeking out of the tube, tape it firmly into place. Cut the tube short enough that the switch protrudes out the back. Tape the switch into place. You now have a homemade laser that's just as effective as any you could buy commercially.

Tips & Warnings
If you accidentally create an LED you will know it because the diode will glow rather than cast a focused beam of light in a single direction. Simply break off the pieces of solder and try it over again. All the materials used in this procedure can be picked up cheaply at a Radio Shack or similar store.
Lasers should never be directed at living flesh, be it human or animal. In particular please keep lasers pointed away from eyes. Though they seem like toys they have the power to do permanent damage to living tissue and should be handled with the utmost of care.

How to Build a Stun Gun

A stun gun is an electrical device used in self-defense that is designed to stop or incapacitate an assailant by delivering a high voltage shock of electricity to his body. This shock will cause the assailant's muscles to seize and he/she will normally collapse for a few moments. This will typically give the person with the stun gun a chance to remove themselves from danger by running away or more permanently incapacitate the assailant. This device is easily available to anybody in America over the age of 18 and can be carried legally anywhere except on specified government or private property. It would seem unwise to entrust a person's safety to a homemade device, so I would not recommend building one for defense against potential attackers. The homemade version that this guide will teach you how to make generates less than one quarter of the voltage of a professionally made model. Because of that I would suggest its use as a deterrent against dogs rather than people. Personally I live in an area with no leash laws and some very large, wild dogs and have found this an effective way of getting dogs to leave me alone when I go out for walks. In this guide you will find instructions on how to build your own stun gun.

Things You’ll Need:
Soldering Iron

Solder Wire

Wire Cutters

Screwdriver

Glue

Disposable Camera With Flash

Scissors

Thick Sheathed Copper Wiring

Five Star Binder/Planner

Building Your Own Stun Gun
Step 1:
Use your screw driver to pry open the back of the disposable camera.

Step 2:
Remove the batteries from the back of the camera.

Step 3:
Find the miniature light bulb that is the camera's flash. Pull it out to the full extension that the wires connecting it will allow. If the wires are soldered in place then cut them with the wire shears. If the wires are wrapped around contact points then just unwrap them carefully.

Step 4:
Cut two equal lengths of copper wire (About three or four inches should do). Wrap each of them to the wires that had been connected to the flash bulb. Touch some soldering wire to the joints and melt it into place with the soldering iron. You now have two much longer wires protruding from the camera. They should never touch, but be within a few inches of each other at all times. The thicker and stiffer sheathed copper wiring you use, the easier it is to accomplish this. Set this aside for the moment.

Step 5:
Cut the plastic cover of the five star binder free using the scissors. Try to keep it in a single piece if possible.

Step 6:
Place the thick plastic coating on the camera in order to sheath the exposed circuitry. Cut out holes for the flash and shutter buttons on the camera, and put the batteries back in place. Then glue the covers in place. You should end up with something that looks a bit like a thick appointment planner with two stiff wires sticking out of the top. Press the shutter button and watch the sparks fly!

Tips & Warnings
Though stun guns have a very high voltage payload, they have a very low voltage amperage. It is amperage and not voltage which can endanger human lives, making these devices non-lethal most of the time. Unfortunately they can cause heart attacks in people with heart problems.
When working with anything of an electrical nature, there is the possibility of being shocked. This particular device doesn't have enough strength to do more than make the muscles of the shocked area convulse, but as a good practice always makes sure to keep yourself grounded, free of static electricity, and always be aware of any body part near the electrical device.

How to Build a Homemade Projector

Large screen digital projectors such as one would use in business presentations or in a personal home theater have become very popular and can be purchased in most stores specializing in electronic equipment. These projectors are connected your computer tower or laptop and can be used to play movies, news clips, still images, PC games, and other presentations. The only drawback to their use is the expense. A cheap projector will cost at least seven hundred dollars, while the high end projectors can cost well over three thousand dollars. However for those with a little ingenuity, it is possible to make your own for just over two hundred dollars. This guide will outline how to make your own digital projector.

Things You’ll Need:
Overhead Projector

LCD Computer Monitor

Computer Cooling Fan S

crewdriver

Foam Strips 10MM thick

Soldering Iron

Solder

Duct Tape

Electrical Tape

PC Tower

Making Your Own Big Screen Digital Projector
Step 1:
Start by gathering the materials you will need. The old overhead projectors such as the kind that used to be used in classrooms can usually be purchased for less than twenty dollars from your local library. A computer cooling fan like the kind that are found in the body of a desktop computer is about four inches square and can be purchased from electronics and computer stores for less than ten dollars. The LCD Monitor will be the most expensive item you will need to find. The cheapest new one you will likely find will cost over one hundred and sixty dollars. If you can find a used or damaged LCD monitor then buy it, only the screen itself need be intact. It is important that the Monitor screen be no larger than the glass window of the overhead projector.

Step 2:
Take the LCD Monitor and use your screwdriver to remove its plastic casing. Inside the shell should be the LCD screen attached to a metal backing.

Step 3:
Detach the data and power cords connecting the screen to the inside of the shell. Remove the LCD Screen carefully, there are delicate wires hanging from the screen's rim. These should not be bent or damaged in any way.

Step 4:
Place the foam strips on two opposite sides of the overhead projector top, just outside of the glass screen. Use plenty of duct tape to hold them in place.

Step 5:
Place the LCD screen face-down onto the overhead projector. The foam strips should hold the face about 10mm above the glass.

Step 6:
Reconnect the power and data feeds leading to your computer tower. Some models have plugs set into the screens themselves and this makes the job much easier. Other models will require you to solder the cables in place. To do this make sure you know what cable goes where first. Then get out your soldering iron and solder. Put the metal end of the cable against the connection point on the screen, hold a piece of solder against the join, and use the tip of the soldering iron to heat up the solder so it melts into place.

Step 7:
Wrap the electrical tape around any bare metal or wiring that you can find so as to avoid the danger of short circuits and electric shocks.

Step 8:
Place the fan against one of the open sides where you can see the space between the monitor and the projector. Duct tape it into place so the fan will blow cool air into this space, then connect the fan to the PC tower to power it.

Step 9:
Plug in the overhead projector, plug in the LCD monitor, and start up your PC to see if it's working properly. Anything that would be visible on your computer screen should now be projected onto a hanging screen or wall of your choice.

Tips & Warnings
The quality of the image you receive will depend on the resolution of your LCD monitor, the highest resolution you can get within your price range is definitely recommended.
The LCD monitor will short out from the heat if a cooling fan is not used and running at all times.