Lighting the fuse!

It may seem a trivial topic at first glance, but is all important in the final analysis!

It doesn't matter if you have spent hundreds of dollors and dozens of hours building a complicated firing train with a powerful high explosive such as RDX with tungsten carbide ball barrings for armor penetrating fragmentation or just a simple salute in a cardboard tube. If you can't light the fuse all your work is for nothing.

I have light or tried to light hundreds of fuses in all sorts of conditions. I have found some work better than others and that is what this thread is about.

If you are using a quality waterproof fuse and it has been water-proofed at the intrance to the explosive device there is no reason why that device cannot be detonated in good weather conditions, in the rain, in subzero temperatures, in the blistering sun, in tornadoes, in hurricanes, and even under water. The topic here is finding the right source of ignition to meet the condition. I have found that in good weather conditions ( no rain, no wind) that the flame from a butane lighter or match will reliably ignite a fuse. However, if your lighter or matches are wet, or if there is even a light breeze, there effectiveness can drop to zero. I have found that setting off explosive devices during a thunderstorm can easily prevent the authorities from investigating it. As most anyone will interprete the explosive flash as lighting, and the loud booming as a thunderclap. The only problem is of course waiting for such weather conditions and trying to light the fuse in the wind and rain. There are many sources of ignition on the market today. Some of these include matches, butane lighters, blow torches, punks, mini-butane torches, and road flares to name a few.

Matches- are cheap and reliable when there is no wind and no rain. Matches require the use of both hands. Which means you can't hold the explosive device at the same time.

Butane lighters- Are cheap and reliable when there is no wind and no rain. They can stop working altogether when cooled to around 32 Celsius. Lighters can be used with only one hand, which means you can hold the device with the other hand.

Blow torches- Are extremely reliable once they are light. Wind and rain doesn't bother them at all. However they are bulky, expensive, and can't fit in your pocket.

Punks- Are probably the worst as they often go out, but can be used in the wind if they are kept dry.

Mini-butane torches- These are just supped-up lighters. The butane is pushed out and burned at a faster rate than disposable lighters, but they don't work when wet or in above moderate winds.

Road flares- These are extremely reliable in all conditions- wind, cold, rain and they are ignited by friction just like a match. They can burn under water because they have their own oxygen. One of the drawbacks is they can be seen miles away, especially the magnesium based ones and they can ignite the fuse at a point closer to the device than may be disired( for short fuses).

I have seen at some tobacco stores a cigarette lighter that is just a few times bigger than a butane, but it has batteries in it and when you push a button it heats up small coils that light the cigarette. This type of device seems promising although I have not tested it in all conditions yet.

I have had some ideas of using party poppers with a small black powder charge to ignite the fuse. This seems like a good setup as you just pull the string. However it could also be a dangerous one if used on a shorter fuse, as the spit from the black powder and the heat could ignite the fuse at a point closer to the device than desired.

Please share your ideas about reliable fuse ignition, and your experiances thus far!

I've had excellent results with making a match pull igniter, and enclosing it inside of a dry condom.

Water-proof, windproof, silent, and only minimal flaring for a few seconds.

I've also seen the cig lighters that have a glowing coil, and they're windproof, so would work well, though obvioulsy they'd not work underwater.

A zippo lighter is pretty much impervious to wind and rain.

Storm matches seem like a good option, as the type I've seen are guaranteed to burn for at least 7 seconds in the most adverse weather conditions. They're windproof, waterproof and also fairly cheap. I'll get hold of some and test them out.

In my experience, getting a lighter damp craps up the ignition system, be it the piezo type or the flint type. Flint lighters seem more resistant to water though.

Nightstalker,

Zippo's have been around for along time! Many Vietnam Veterans I've talked to say that the zippo is the best lighter ever made. It is constructed with a Stainless steel case and the only thing you need to do is replace flints and fuel and wadding. A great advantage of the zippo I think is that the fuel is a liquid absorbed by a wick, so unlike butane that blows away before burning, the fuel on the wadding remains in contact with the burning fuel keeping it from going out in the wind. Also a few drops of water wouldn't hurt, cause the beads of water would just run off the wick without be absorbed. I think zippo lighters have great potential. Thanks for bringing them up!

I would like you to tell me more about the match pulling device and how to make one! They sound like they could be made as a unit and be implemented into the design of the explosive device; it's own personal, self-contained firing system.

Note on butane lighters: I'm a smoker and in the morning during the winter months when I go sit in my car and try to light up a smoke with a lighter thats been sitting in the car overnight, the lighter will not work because the cold temp has caused the butane to condense into a liquid. If you simply put the lighter in the palm of your hand and make a fist around it then bang it hard against the palm of your other hand several times and then strike it, it will light. I think this shaking and banging gets the butane to go back to a gaseous form. This is good to remember when trying to light a fuse with a cold butane lighter.

I am all for electrical ignition. No fuse will give you the control over your device like an electrical ignitor will. When you light a fuse you must then get out or away but if you use electrical you are already as far away as nesicary before any thing gets lit.

Maby it's a comodity but they are quite cheap to make. you can buy some multi strand wire just about anywhere so anybody can get them. I only use estes because I'm lazy and their reliable.

I have dreamed about hundreds of dets before and got the hang of electrical ignition on the 3rd try and can make a reliable det in about 3 min. that would go off under water and just about any weather, (save raining fire, in which case explosives would be redundant anyways),. I have no fuse and would like to use it out of conveniece but right now am a little cramped for cash.

As for lighting fuse. I like to incorporate KClO3 in to the end of the fuse so it can be ignited with a drop of drain cleaner H2SO4. It aint that watter proof but it beats standing their in the wind with your hands cupped around a lighter on a windy day.

I dunk the first 1/4 in. in a saturated soln. of KClO3 and dry and repeat untill I can see the white cristals on the end of the fuse. This is quite reliable once you get the hang of it. I'm sure it would be easier if it were black match or other home made fuse so you could use the chlorate as the main oxydiser and skip the diping. It's experimental.

I Think that electric ignition is a wonderful thing, because you can set a timer for weeks even up to a year for the device to go off! However I have found that electrical ignition can be a pain, because they are bulky and it takes time to set up the wiring and the wires always get damaged in the explosion, plus after the det. you have to go pick up your wires and its not easy to roll up 500 ft. of wire and drag away a car battery when your trying to get away. For me, fuse is much cheaper than the electrical fuses that can be bought at hobby shops for model rocketry. Then you have to pay for the batteries. I think that electrical ignition is best for certain applications, but for normal firing excercises and explosive testing, fuse works great. For me there's just something special about lighting that fuse, and once it's light it just burns mindlessy to DESTINY, the Enevitable! Boom!

I like your chemical ignition idea. I have 4 pounds of Potassium Permanganate that I got at Sears, sold as Iron filter regenerater. I have done some experiments, mixing it with glycerin. After they mix, about ten seconds later it begins to smoke and then it begins to deflagarate with a purple flame. I haven't figured out yet a suitable setup for a chemical firing unit consisting of the two chemicals.

I like your chemical ignition idea. I have 4 pounds of Potassium Permanganate that I got at Sears, sold as Iron filter regenerater. I have done some experiments, mixing it with glycerin.

Try an 80:20 mix of chlorate and sugar, ignited with a few drops of concentrated sulfuric acid. I think you'll find it adequate... The acid may be kept in a sealed glass tube, broken at the time desired for ignition.

There's allways the M60 pull igniter too- Nice & waterproof if properly applied.

Cigarettes or Cigars are very good at lighting fuse.

Now that I think about it, I have used the red hot cherry at the end of my cigarette to light fuses. This works very well even with a howling wind, although you will have to light your cigarette in your car or house or cupped in your hand. I have also drilled a hole in a cigarette and fed the fuse through it as a time delay. Usually about 5 minutes for regular or wide cigarettes and 7-8 minutes for the 100's. those of you who smoke know that a cigarette will burn in the rain even after a few drops of rain has gotten on it and it can be protected from wind and rain by cupping it in the hand. I am pretty sure most tobacco companies add a propellant to the tobacco so it will keep burning. So smoke another one!

When using fuses, a good jet-butane+glowing wire lighter is what I normally use b/c it is almost impossible to put out by wind (it acts up when wet though). KMnO4 + Glycerol does have good initiation properties above 10*C, its a good alternative for those who don't like carrying/using conc. H2SO4 during shitty weather.
I hapen to have thousands of plastic containters 1.8ml each with resealable soft-plastic lid, I let my waterproof fuse in through a pre-poked hole on the bottm, seal it with epoxy/hotglue, fill it up with KMnO4 and close the lid (I usually make a bunch at the same time). To use it, I simply use a syringe with thick needle to poke through the lid and inject it with glycerine. Thick needle creates a hole large enough for gasses to escape and prevents rapturing of the container. This set up will work under any conditions with low temperature being the only exception.

For those who prefer using the electronic ignition method, but are worried about winding up the wire, I have an idea.

One could use a simple golf cart motor, a homemade pulley wheel (think golf cart hub :D) and the same battery you use for ignition. Fashion a little rack for it with a handle. One could even incorporate the battery and detonator box in to the rig. One unit provides wire, reel, battery, button and a power winder!

With no power to the motor, you could play out the wire as long as you needed too, then when the dream is over, juice up the motor and reel that wire in FAST, pick up the unit and be out like a flash.

More creative minds might regulate the speed of the motor with a simple motor control to allow for smoother reeling and create a guide to keep the wire neat on the spool……I am horrible with art, but picture and old bait-casting rig that you dad or pap may have had in the garage. In a pinch, you hand (gloved -- think friction) would do.

The modern ones have a guide that moves back and forth to get the line to lay flat on the spool. When the wire gets to short to be serviceable (after several dreams) you simply replace it like you would worn fishing line.

OK…..I know. I have WAY too much time on my hands…
Carry on.

I never do any thing big enough to require 500' of cable and if I did I wouldn't worry about picking it up in a hurry as it takes about 5 min. for the pigs to show up so I would be done and playing video games before they showed up. I have no need to do large charges any ways, it is pointless and a waste of explosives. I like my booms mind you but would like to test wrather than waste good explosives on a simple boom.

Altas, my man! It is never a waste when an explosive detonates, that's what it was made for. Listen, you are a pyromaniac or your not! Pyromania is a desease just like alcoholism or drug addiction. We are ever persuing a greater high until it eventually destroys us! Drug addicts always want to smoke just a little more dope this time then they did the last time, trying to get that original feeling they got the first time they used, or for us the feeling we got when we blew up our first mailbox or set off a pipebomb. We are always wanting them bigger and better. We want to feel the shock wave crashing into our bodies, the smell of the chemicals in the air makes us grow a big rubbery one. The rush of addrenaline you get as you anticipate the blast, then when you hear it it is like having an orgasm---makes you feel real good! Then you run away to do it again another day. Don't get me wrong, just as all drug addicts aren't the same or the same severity, it is the same with pyro's. If you don't get any feeling of satisfaction at all I question wether you are a pyro at all.

I am 50% scientist , 30% thrillseeker and only 20% pyromaniac.
I doubt somebody here is a clear pyro, and the upper statement is not absolutely right. The drug addict takes only one and same dope, we want to make the devices better every next time. Our looks more like ham-radio, except it is dangerous.

HA HA HA!

I'm Laughing!!!!!!!!!

I'm rolling on the floor!!>>>>>><<<<<<>>>><<<!

My face is red and my whole body is shaking........

I use a pocket torch. It is butane refillable like a jet-ligher but it can hold a lot more, is hotter and allows your hands to be at least 20 cms from the flame.

It is quite windproof, fits in the pocket, but needs a flame to light the butane. I don't have any problems lighting it though.

You may have seen it when I lit some flash/mixture in the "easiest Al powder" thread.

Who need 500 feet of wire? Behind cover and with ear plugs, 10m speaker cable is enough for up to a kilo TNT. Also the shock wave feels better! ;)

And who needs a car battery? A christmass bulb filled with AP only needs a 9V block battery! :)

The cable is 10 cent per m, you can roll it up and dispose it a little away from the blast. You might leave the cable there for the next dream ....
When the cops catch you, there is only a small battery on your person. :D

Well, you're right about needing only 10 meters IF you didn't bury the charge. I have seen rocks the size of my head falling down only a few meters away from me (standing 50 meters from the blast) because I buried the charge. Wouldn't want to stand in the wrong place when one of them comes down from 50-60 meters altitude do we?

In one of my vids i buried 1,2 kg's of AN/NM/AL under a pile of rocks, the rocks where "propelled" upwards by the blast and I was nearly hit by one eventhough I was standing behind a hill.

If I am going to eventualy destroy myself if I am a pyro then I will have to say that I am no pyro.

Explosives are tools that are simply fun to use. When I dream of something it is to learn how to use the tool better. When I have perfected the art of explosives use that's not to say that I will drop the craft and simply move on to something else. I prefer to continue to use them but start using other weapons in conjunction with them to make myself better at combat. I have always had a keen intrest in weapons of every sort. I not only think of the weapons potential of explosives but I think of the potential of every branch of science from electronics to aerodynamics. To limit myself to explosives would mean that all of the other potentialy revolutionary weapons I could create would never exist.

The term pyromaniac is someone who is obsesed with fire, This would be me if all I did was play with fire, this is not the case. I would employ any knowledge or technology possible to make a weapon better at it's job. If a true pyromaniac were to make a weapon it would probably be a flame thrower, where as if I were to make a weapon it would probably be a directed energy weapon with an thermal imaging scope with 10-40X magnification and a power output rating in terrawatts(yeah, maby).

Without employing other branches of science in to the development of weapons they would be quite ineffective. You need to know about optics and electronics to create the scope, you would need to know about plasma physics and magnetism to create the projectile or laser device, and you would have to know metalurgy to create a barrel that could stand up to the abuse and temperature and to create enough protection for you operate it safely.

To limit ones self is like following all the rules society creates, it's just not right.

Lets get back on topic, shal we?

A good cig lighter usualy get's the job done for me but when it fails is the only time I use blow torches and flares and such. I like to make straws packed with KNO3 and sugar just for the hell of it( I like to light them and throw them) but once lit they never go out, so they can be a cheap alternative to a flare for starting fuses. There are diffrent things you can add to make them burn slower like wood meal, and they could be friction started like matches if a bit of safety match head is pasted on to the end. These make great fire starters as well. They are much more reliable if you use a paper tube and melt the sugar in the mix to make a solid mass.

I presonly use this, it is a Kmn04 plug igniter made with .25" brass hobby tubing, a bit of epoxy, steel wire and a gelitine pill case.
A: is the visco fuse
B: is the kmn04
C: is the epoxy end plug
D: is the washer and tape that hold the kmn04 in
E: is the pill case withe the glycerin
F: is the.25" brass tube
G: is the steel wire

These units are very easy for me to make, It costs about five bucks to make fifty of them. Ive even got alittle production line for making them, and they are easy enoughto use, put in fuse squease end to crimp, pull wire, the wire cuts through the gel cap releasing the glycerin 8-2 second later the fuseis lit(depends on the tempreture)

+++++++++

JPEG is the wrong format for use with computer graphics. Use GIF in the future. NBK

Not bad, I like the fact that it crimps on to the visco. I would wrather use H2SO4 + KClO3 as it lights faster and in any temp. what would prevent you from doing that? Permanganate is alot more expensive than KClO3 and sulfuric is alot cheaper than glycerine. Unless you can get the permanganate easier, it seems like you use the expensive route.

I don't have any ready to go sources of potassiun chlorate around, but maybe it can be made by nuetralizing concentrated hydrochloric acid ( sold as muriatic acid at home depot) with Caustic Potash ( sold in gardening stores). Maybe that will make potassium chlorate! I can easily obtain 92% sulfuric acid sold as a drain cleaner at ace hardware stores.

But tell me something, what kind of setup do you use to react the materials so they will light a fuse? Same as above??

I still think zippo's kick ass!!!

I'm not sure if any of you have seen the movie the Saint with Val Kilmer, but in the movie when he is in a sewer running from the mobster's he pulls out a small metal tube filled with a pyro technic comp. that cuts through a weld. Also later in the movie he uses another one of those tubes to ignite gasoline that is on the ground. I know this is just a movie, but it's a valid idea. What if a guy could fill a metal tube with a pyrotechnic comp. and just ignite that chemicaly and use the flaming jet to ignite a fuse or several fuses! It could probably burn for up to ten seconds or more, but you'd have to ware gloves as the metal tube will get hot!

I love the picture of the M-60 pull igniter. Are these devices available to civilians?

Try this when lighting only one fuse. The only limitation is very wet weather, as wind does not affect this method. I personally use water proof matches.
Thread the fuse between your fingers from little finger end to pointer finger. ie. Over little finger, under ring finger, over middle finger and locked in place with pointer finger. With thumb hold match with match head pressing directly onto the end of your fuse. Hold matchbox in other hand and strike flint over match head. You dont need a furious momentum to strike a match. Just drag it over. The match will flare. It is this initial flare of the pyro material the matchhead consists of that you need to light your fuse. As the match head is in direct contact with fuse, this method works every time.

KOH + HCl ==> KCl + H2, no chlorate, try electrolysis.

My blow torch has yet to fail me but like I said, I prefer electrical over fuse.

I don't have any ready to go sources of potassiun chlorate around, but maybe it can be made by nuetralizing concentrated hydrochloric acid ( sold as muriatic acid at home depot) with Caustic Potash ( sold in gardening stores). Maybe that will make potassium chlorate! I can easily obtain 92% sulfuric acid sold as a drain cleaner at ace hardware stores.

But tell me something, what kind of setup do you use to react the materials so they will light a fuse? Same as above??

I still think zippo's kick ass!!!

I'm not sure if any of you have seen the movie the Saint with Val Kilmer, but in the movie when he is in a sewer running from the mobster's he pulls out a small metal tube filled with a pyro technic comp. that cuts through a weld. Also later in the movie he uses another one of those tubes to ignite gasoline that is on the ground. I know this is just a movie, but it's a valid idea. What if a guy could fill a metal tube with a pyrotechnic comp. and just ignite that chemicaly and use the flaming jet to ignite a fuse or several fuses! It could probably burn for up to ten seconds or more, but you'd have to ware gloves as the metal tube will get hot!

I love the picture of the M-60 pull igniter. Are these devices available to civilians?

Oy, where to start?

Anyone who can search this forum and says he doesn't have access to chlorate is not very motivated. Several synthesis routes from OTC are here.

Regarding your speculations on chemical reactions-. Please, more searches and study, less wishful thinking!

Yes, Chlorate/H2SO4 igniters could be constructed similar to the above, but you'll need glass for containing H2SO4 not a gel cap. A mechanical striker to break the glass has been used in military versions.

Glad you like Zippos, Go here! (http://4eyedanimation.com/Zippo/zippo.htm)

Forget everything you've ever seen in a movie or on TV shows regarding explosives, pyrotechnics and most especialy gun handling. There's a tool that will cut metal as described called a pyronol torch. You'd need an asbestos suit and supplied air to use it safely. There is a "tube with a pyrotechnic comp. and just ignite that chemicaly and use the flaming jet to ignite a fuse or several fuses!" It's called a road flare or port fire. There are also hot tip fuse lighters for blasting that serve a similar purpose, but are more like a sophisticated wire sparkler in construction.

There are pull wire fuse igniters available to the public, try Firefox for components and instructions to manufacture your own. Ask the paintball players about these- You may find an M-60 on the civilian market, but the special primers to reload them are scarce.

Readily available from explosives suppliers ie. licenced hardware stores, is a device called a Two Minute Fuse Lighter. Some are cardboard tube, others are very similar in appearance to a sparkler. Matchhead type composition for striking and burns with intense heat for, yep you guessed it, two minutes. You dont need a licence to purchase these. Very handy and reliable items.

1. Cigg's have KNO3 added to them to keep them lit. (for the person talking about it)

2. Zippo's are only good if you have the lighter fluid container in your pocket. Cold days mine fails to light occasionally (-20 c -) and their design causes them to lose alot of the fuel because not air tight. (especially in hot dry weather).

wouldn't one of those christmas lightbulbs connected to the end of a piece of fuse then water proofed work. then all you would need is to carry around a 9V battery and a couple of short pieces of wire...

such as variations of what is on the following link.
http://members.aol.com/nonillion/igniter.html#Xmas

zippo for lighting the fuse
it is not good as simple chinese gas lighter, it is best way in the wind, and in the rain

Flip Flash units are available in surplus stores--remember the 110 pocket cameras?
One of the bulbs, wired to a piezo sparker from a gas grill. Match heads on the outside will ignite, as will BP.

I got instant fame a year ago, using this method with kerosene at a park.

Of course, I had a backup device. Just in case.

I think probably the easiest and safest way would be to make a small unit with a fewn NiCad cells and some nichrome, simmilar to the no-flame cig lighters discussed at the start. It would not be hard to have a nicad pack, to a switch, to a short length of high-guage nichrome, the nichrome would glow red hot allowing you to ignite the fuse. the batteries would have to be of low internal resistance however for the high-gauge nichrome (which is why I suggest NiCad) as high guage nichrome would not melt as quickly through repeated use.

If you're going to use the nichrome wire, why not just make a bunch of nitrocellulose lacquer-covered squibs, and use a battery-operated Estes rocket engine igniter? You can't save the wire, obviously...but it's fairly simple.

...and use a battery-operated Estes rocket engine igniter?

I hate those Estes rocket initers. I bought 20 pieces of that shit and only 7 worked as they should. If you have an important blasting job to do (well, every bang is important) I woudn't trust that bullshit.
Maybe I got a bad lot, but to my mind they are not worth the money.

Plus, they only have a 5 metre cable :rolleyes:

The crocodile clips at the end are easily damaged - an improvised blasting cap made from a 5.56mm round filled with HMTD deformed one clip and removed the other clip (which flew off somewhere). Maybe I should have used longer wires between the clips and the cap.

NB - the cap was prepared immediately before use due to HMTD being incompatible with the brass casing. I also positioned myself so that there was a good sized tree between me and the cap.

Well yeah, definitely a little-underpowered. But one could easily make a beefed up version.

Never had any problems with the one I had...of course, that was ten years ago...

I have also been interested in using flameless lighters to light fuses. Not to get OT, but the filament from a lightbulb works great for lighting stuff from far away if you don't want to shell out the cash for NiChrome. Perhaps a cheep timer could be set up to allow one to not have to run all that wire.

Besides using electrical ignition for longer range use, I prefer use of my zippo when actually lighting a fuse. I'll use disposable lighters and the "lighter guns" for something not too important, but I really prefer my zippo as it is quite windproof and works well under a lot of conditions when the disposable ones will usually decide to act up and be a bitch.

I have to agree with electric matches, or a not so easy but very cheep way is to get a peice of steel wool pull out a thread about 2" (5 cm ) long and stick it through the fuse (you need to punture the fuse with a needle first) then wrap the fuse a couple of times in it and atatch the 2 ends to wire, run the wire out and touch it to a a car batt or any 12 volt source. it takes a couple seconds to light but it works

Phreak

I use quest rocket ignitors.They are mych better (my opinion) then the estes ones. I NEVER failed to ignite my fuse with a quest ignitors and, they are pretty cheap. +- $2 for 6. All you need is:
-2 peaces of copper wire 10cm each (alot of fine wires, not 1 big one)
-a quest ignitor
-9 volt battery
-some paper tape
when you buy quest ignitors you will find a sort of sticker in the package, these you stick around the ignitor. used to mark where you should put the crocodile clips.
But, in this case you wont need them! :) where you are supposed to put the crocodile clips you put one of the 10cm copper wires above the sticker , but below the ignitor (plastic removed around the wires of course ;) ) so now you will have a ignitor, with the sticker attached that also holds the 2 wires connected to the ignitor. Press the wires hard against the ignitor with thumb and pointing finger. just to make sure the wires have good connection with the ignitor. now you take the black part of the ignitor, which produces the flame and hold it against the tip of the fuse and tape it with the paper tape. also tape the ignitor and always press it hard, for good connections. than tape it with duck tape if you want it to be used in rain.
Now all you will have to do when you want to ignite the fuse is taking the 2 wires (other ends) and press them against the + and - side of the 9volt battery.
Hold for like 1 second till you hear Pschh, now the ignitor has set the little black tip on fire and the fuse will instantly catch fire too. now run like hell cause your fuse is burning ;) I hope this will help for some of you that have trouble with igniting there fuse, this is a cheap and pretty good method for fuse lighting, it ALWAYS worked for me but when you have a bad contact, or the battery is dead you are in sh*t. So bring your zippo just to be sure that if your ignitor doesnt fire you can still light you fuse with the zippo ;)

Isn't it easier to use a little NiChrome wire? You get 150 ft for like 5-6 dollars on eBay.

I pondered over a reliable method of remote wireless ignition for some time and have created a masterpiece. My main usage is for airsoft games - I got hold of some electrically fired mines, the same idea as a claymore, but with a small amount of BP, firing BB's or dried peas. I used to have to run out a length of speaker wire and use a 9V battery to set them off.

I got frustrated, because there was never enough time to run out the wire and conceal it during the game and it was a pain to have to collect it all up afterwards. So I looked into another way of doing it. Remote doorbells were considered briefly, but they are too susceptible to interference. Most remote garage openers suffer from a similar problem.

I have now found a remote sytem using "Keeloq" protocol, which appears to be very secure. I have a small three channel keyfob and I've constructed a box to include a circuit with the hybrid receiver board, output transistors, a battery, keyswitch and quick connect speaker terminals.

I get a range of up to 100M with it, which is fine for my main usage, it should also be enough for detonating larger explosives. As far as security is concerned it uses a code hopping system to avoid "code grabbing" and, as it is a data signal that is sent, even if someone else is using the same frequency, it won't go off by accident unless the codes match.

The hybrid board outputs 5V logic levels high until switched - perfect for hooking an NPN transistor to. Spec sheet PDF here (http://homepage.ntlworld.com/maniacdoug/datasheets/keeloqhybrid.pdf).

I don't have a copy of my circuit schematic on pc, but it is just a simple case of fitting a 5V regulator to the input for the board and hooking an output transistor per channel with 9V accross it.

The channels can be configured to be latching or momentary in various combinations.

I got them from Farnell (http://www.farnell.com), the keyfob costs around £10 and the hybrid board around £15. Including the other components necessary, it cost me about £40 to make a three channel box.