Custom30 wrote "I'm gonna rig a matrix of high powered lasers in the companionway
...Lasers it is!" ==> OK, this is doable - not really high powered though. Since ray guns
are not off the shelf items one will need to do a bit of work to make them - still, it is unlikely that any third world country has laws restricting them, nor are their agents likely to recognize them as dangerous.
One can recycle an old microwave oven
into a pest and weed exterminating device. Take the microwave oven
apart and keep the magnetron, power supply, fan, light, and on/off switch. Using the sheet metal from the oven or a galvanized stove pipe, mount the magnetron at the front with the microwave emitter centered and pointed out – it should be set back from the end about six inches or so to shroud
the beam. Use the same holes that bolt the magnetron to the inside of the pipe to affix the forward hand grip – probably made from wood. Mount the fan in back of the magnetron so that it will blow air over the power supply which is mounted at the back. Use the bolts that secure the power supply to mount the rear hand grip – this hand grip is hollow and the power cord* runs out of the handle to plug
into an extension cord. The hand grip also mounts the trigger type on/off switch which will only stay on while it is being held back with the trigger finger. Mount the oven light** over the power supply and change to a red bulb if possible (to let the user know the unit is on, and to protect night vision). Use some metal screening material, perhaps that found in the oven door, to screen
the rear opening of the pipe. As an option, one might affix an old laser pointer** to the top of the magnetron, run by the power supply, to show where the invisible microwave beam is being directed.
* For portable use – perhaps on a boat – one could power the unit for a limited amount of time using a small twelve volt motorcycle battery
and an appropriately sized inverter
** To save power and up the visibility, dispense with the small oven light and instead of a laser pointer, use an array of four write heads from an old recycled CD/DVD burner. Cheap
but powerful, this would outline the invisible microwave beam with four red dots. Note that the laser array is likely powerful enough to cause temporary blindness if directed into someone’s eyes. The trigger could be wired so that as the trigger is pulled back the laser array comes on, continue pulling and the microwave beam comes on.
When on, the magnetron will emit a compact stream of microwave energy – this should be tested by aiming the device at a small glass of water
. One should be able to get a feel for the direction and range of the microwave beam by noting how long it takes the water
to boil. In general, microwave energy is not good for living things as it excites the water found therein which heats the item up. An insect, perhaps a cockroach, is a small quantity of mostly water contained in a chitin shell – and this small quantity of water can be rapidly heated to over the temperature at which insects die (around 105 F). A similar thing happens to the leaves of plants (weeds). Microwaves will go through some stuff like plastic, wood, concrete, and earth (like ground penetrating radar
does) so for safety
you should know what is on the other side of walls – and this feature might be used to kill pests inside the walls (cockroaches, mice, etc). Some experimentation will be needed to determine the range and penetration of your unit. Microwaves do NOT penetrate metal, so any metal surface in the beam will act like a mirror and reflect the microwave beam – if the surface is flat the beam will be reflected at an angle (the angle of reflection is equal to the angle of incidence), if the surface is convex the beam will be dissipated, but if the surface is concave the beam may become concentrated (at least for some distance). Some prudence is indicated here.
If more power is needed a bigger commercial
unit might be obtained, and to make it portable, get a small generator
and mount both on a small cart. More power might be needed to reach further underground to get rid of various pests (like ants, termites, gophers). This unit might also be set up to ‘burn’ an intruder – especially one that is in a fixed or limited location like a porch. Aimed at an intruder’s head
from a concealed stationary location (trap) from close range, the intruder will not even know that they are under attack until the attack is becoming effective. Using a portable unit, it might be possible to ‘burn’ an intruder through a relatively thin wall or door – again the intruder might not know they were under attack. When thin metal is placed in a microwave oven there are usually some spectacular sparking effects and the metal heats up – if the intruder is holding a metal weapon such as a knife or a gun, such effects might cause the weapon to be dropped.
One could scale the concept
down and just mount five of the DVD
write heads in a flashlight body arranged in a ‘+’ array. This would use a lot less power and would look to the casual observer like a common flashlight. There are instructions on the internet
for salvaging and remounting them – the videos show that one can pop a balloon from across the room. Shined into the eyes of a miscreant, it is likely to at least disrupt his night vision while leaving yours intact. It is possible that a couple of seconds of continuous exposure may cause temporary blindness since the human eye will refocus the relatively diffuse beam on the fovea of the eye. With enough heat to pop a balloon, it is likely that such exposure will be painful and the exposed target is likely to respond with the traditional ‘hands follow hurt’ by putting his hands over his eyes. This will likely disrupt his offensive posture if he is holding a weapon and give you time to take some appropriate action.