How to make Balloon-popping Laser etape 1

How to make Balloon-popping Laser

The balloon popper is very similar, but this time the transistor passes a large current through a small resistor, heating it up until it is hot enough to pop the balloon attached to it. The power flowing through the resistor is likely to eventually destroy it. Fortunately, the resistors are cheap and for this project can be considered disposable


What You Will Need

You can buy laser modules from standard component suppliers like Farnell and RS, but they tend to be very expensive. So look online, where they should cost no more than two or three dollars. You’ll need the parts shown in the Parts Bin.

Assembling the Gun

The first thing to say about the gun is that you don’t actually have to make it. You could just use a ready made laser pointer. Laser pointers do not look very gun-like, so as an alternative to this design you could modify a pointer by adding a handle and trigger. The gun (Figure) is deliberately made as small and unimpressive as possible to increase the impact of its balloon-popping and can-jumping capabilities. Figure shows the schematic diagrams for the gun. It has only a few

components and they can easily be soldered together without the need for a circuit board. The components are mounted inside a u-section aluminum strip. Lengths of this can be obtained from hardware stores. The components could just as easily have been used on a strip of plastic or even built into a toy gun. The battery clip terminals fit through holes made in the aluminum so that when a PP3 battery is attached, it forms the handle of the gun. The resistor limits the current to the laser diode module. Resist the temptation to buy just a laser diode; instead, look for a laser diode module. The difference is that the “laser diode” will not have a lens, so you will not get the tight beam of a laser

Step 1. Drill the Aluminum Chassis

The u-section aluminum that the author used is shown drilled and filed in Figure 5-4. Be careful to make the holes for the battery clip big enough to ensure that they will not make contact with the aluminum and cause a short circuit. Lay out the components as they will fit onto the chassis and mark with a pencil where you need to drill. You will need a drill bit that’s the correct diameter for the toggle switch and a larger bit to make the holes for the battery clip. After drilling, file off any burrs in the aluminum and file the holes drilled for the battery clip into a square so the clips can fit in place without the contacts touching the aluminum. Try it on for size (Figure 5-5)

Step 2. Solder Everything Up

It is easiest to solder together all the components before fitting them into place. It also means that you can check that it works okay before you glue everything down. Using the wiring diagram of Figure 5-6 as a guide, shorten the leads of the laser module, battery clip, and resistor to the right lengths. Strip the ends of the insulated wires and solder the components together as per the wiring diagram. After everything is connected up, try operating the switch to make sure the laser lights up before moving on to the next step

Step 3. Final Assembly

Fit the retaining screw over the switch and tighten it with pliers. Then, using either epoxy resin glue or a hot glue gun, glue the laser module and battery clip into place. Figure 5-7 shows the parts soldered and glued into place. Testing the Ray Gun The Evil Genius likes to test laser guns with the aid of a pet. Shine the laser in front of your pet (avoid the eyes) and watch them try to catch the red spot on the floor or on the walls

Cats are much better for testing than dogs, because most dogs will abandon the chase once they have worked out that they cannot eat the little red dot. Cats, on the other hand, will happily chase the elusive dot around the room for some considerable time. In this respect, they are somewhat similar to minions

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