Remote detonations

[xoo1246]

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<small>[ December 28, 2002, 01:00 PM: Message edited by: xoo1246 ]</small>

[Ctrl_C]

<a href="http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=5;t=000889" target="_blank">http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=5;t=000889</a>
<a href="http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=5;t=001024" target="_blank">http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=5;t=001024</a>
<a href="http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=5;t=001166" target="_blank">http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=5;t=001166</a>

[Tyler_Durden]

There have been threads on this. There has also been extensive discussion of the use of a cell phone for detonation.

If you didn't search, do so. If you did, and didn't find it, try some more.

edit: i didn't see ctrl_c's post when I posted this... refer to his links for the threads I am referring to.

<small>[ May 12, 2002, 11:32 AM: Message edited by: Tyler_Durden ]</small>

[xoo1246]

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<small>[ December 28, 2002, 01:00 PM: Message edited by: xoo1246 ]</small>

[Anthony]

I've just tested a cheap cordless phone and can get about 200 yards away with rough line of site and get a dial tone. It's about 150 yards with the base unit inside the house.

The page handset feature could be used for electrical initiation, but I'd rather have the base unit near the charge and carry the handset as the remote control.

I figured when you press the button on the handset to get a dialtone, this could be used to set off the charge. I figured that the base unit would either put a voltage accross a couple of the line line pins, or short them creating a circuit. If it shorts a pair then you could just connected a relay trigger to the pair, which switches on the circuit for your ignitor/blasting cap.

A quick play with a multi-meter and the phone though and I can't find continuity between any of the pins on the phone plug with the handset off, or when it's trying to get a dialtone. I must be doing something wrong...

[Wicked]

A beeper would be good, replace the speaker with an "estees modle rocket igniter" and then have that in a small ball of BP, that should be enough to set off most things. then just put the exploseive around the ball of black powder, and away you go. but be sure to duct-tape it in place, and that the wires arent connecting on the ignighter. MAYBE you could coat the part before the small ammount of black powder with some candle wax.

[Ctrl_C]

not enough voltage or current. you would need a relay and another power source (more powerful battery). refer to the second link.

[Wicked]

Yeah, I just thought of that, make it complete a switch to a nine volt.

[xoo1246]

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<small>[ December 28, 2002, 01:00 PM: Message edited by: xoo1246 ]</small>

[Wicked]

MMMM, i was thinking more like a small motor connected to a nine volt and shit so it would complete a switch. :)

[Omogen]

yes if you have a beeper and an old cellphone dont worry about the volt...just connect the speakerwires to a relay and a 9 volt battery and when it rings it closes the circle and bang...not so hard

will try it with a kitchen timer.

[PYRO500]

The only problem is that the relay may not energise at such a low voltage, you should go for a solid state switching method such as a transistor, or even better an SCR witch will conduct across it's anode and cathode untll the passing currnet is gone ensuring reliable switching.

[xoo1246]

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<small>[ December 28, 2002, 12:59 PM: Message edited by: xoo1246 ]</small>

[Moto Kaken]

The model with vibrator will work finely, but if your beeper have no vibrator, use this circuit.
<a href="http://www.geocities.com/thecuriosity_jp/foralarm.jpg" target="_blank">http://www.geocities.com/thecuriosity_jp/foralarm.jpg</a>
Use 2N2222 or larger transistor instead of 2SC1815,and 12V battery for Vcc.
Connect the wires for piezo-speaker of your beeper to "ALARM", and the electric detonator to "LOAD".
If it didn't work, connect the base of the transistor to "ALARM(+)" directly.

[xoo1246]

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<small>[ December 28, 2002, 12:59 PM: Message edited by: xoo1246 ]</small>

[sinstar]

A good book on the subject(if you hav'ent read it already)would be CIA Remote detonation, PDF 1,5MB.

[Zambosan]

The circuit posted is good in concept (half-wave rectifier -&gt; low pass filter -&gt; common emitter amplifier) but most igniters require several amps of instantaneous current to get hot enough to ignite. I've actually tried using 2N2222's before for just this purpose, and couldn't get enough current through it to start an Estes igniter. There is an Icc(max) for all these devices. Also, even if the voltage is high enough, you wouldn't get enough current out of a piezo driver circuit like that on a cell or pager; piezos are extremely high impedance (hell, they're pretty close to a pure capacitance). The vibrators are ideal since they are reasonably high current, and are driven with a constant signal, not an oscillating one. So you can ditch the diode & capacitor, although you'll still need a switching element that has enough current carrying capacity & high enough gain. I'd actually recommend a FET or optoisolated-FET; I've had great success with International Rectifiers' PVN012 opto-FET relays... lovely little devices, look 'em up.

[Moto Kaken]

you are right, Zambosan.
2SC1815/2N2222 is poor choice for the purpose.
But I have tested the circuit with my timer, and it worked well.
I have very small light bulbs(4.5V/200mA or so). The circuit could drive the filament for short time. Anyhow, the circuit isn't used twice. <img border="0" title="" alt="[Wink]" src="wink.gif" />

In Japan, we can buy prepaid mobile phones without ID(not regular, not cheap).
It is very useful for illegal purposes, but I'll never ignite detonators in Tokyo from Buenos Aires. :D
I have DTMF encorder/decorder chips, FM transmitters, and a cheap(.8$) FM radio. It is not difficult to make low-cost remote detonation systems with them....

[xoo1246]

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<small>[ December 28, 2002, 01:00 PM: Message edited by: xoo1246 ]</small>

[Zambosan]

I've used a Mitel MT8870 DTMF decoder IC in conjunction with a Motorola 68HC11A1 microcontroller to create a multiple-tone land-line remote controller. When active, it would pick up 15 seconds after the 4th ring, and listen in for a window of 30 seconds. This would let you install it on a line with an answering machine. An 8-digit PIN is (was, I partially disassembled it quite a while ago) required to access the device, after that two-digit, * terminated commands were used; e.g. 10* means energize relay 0, 00* is de-energize relay 0, 12* is energize relay 2, etc. Worked well, but the only caveat I have about the 8870 is its ability to filter & detect higher DTMF frequency components (toward the *, or D key if using a 16-button pad) got pretty flaky, especially on a noisy connection. Might have had a lot to do with my circuit construction, though, since I was using a breadboard. I should have isolated the DTMF decoding onto a dedicated PC board. At any rate, I can certainly offer advice if you run into issues building one of these circuits.

Edit-just want to clarify; it will listen for the PIN for 30 seconds. If it detects a valid PIN, it will hold the line open until you either tell it to hang up (# key) or it detects inactivity for a solid minute.

<small>[ June 18, 2002, 01:44 PM: Message edited by: Zambosan ]</small>

[xoo1246]

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<small>[ December 28, 2002, 01:00 PM: Message edited by: xoo1246 ]</small>

[DeAd]

This is realy low tech compared to some of the ideas posted but I made an ir remote initiator system for rocket launches. With repeaters for line of site and range considerations. Take it one step further and you can recieve information from test site to. I've been looking for a laptop with ir data port seems like that would add a professional look to it all.

[xyz]

A low tech way that you could do this that requires little electronics knowledge (but it can only be used for small devices as you don't get much range with it) is to get a remote contol toy car or other remote control toy and replace the motor with a relay or simply an ignitor if the current is high enough. The effective range will depend on what sort of toy you use. You probably won't get any better than 50m or so unless you use a remote control aeroplane, in which case you may get a range of 150m or so. I wonder if you could attach different length aerials to them to change range?

Just a thought
-------------------------
Yeah, a thought straight out of the ACB :mad: -Zaibatsu

<small>[ September 30, 2002, 11:08 AM: Message edited by: zaibatsu ]</small>

[Mick]

also, another vital point with remote detonators, is the detonator needs to be small enough that is completly distroyed by the explosive.

the more you leave at the scene the more ways they have to find you.

[McGuyver]

In a herbach and rademan I saw a laser pointer operated target game. You just have to hit the bullseye and an alarm sounds. This could easily be modified so that when the bullseye is hit with the laser it sets off a igniter or something.

[xyz]

Sorry about that, I knew I'd seen it somewhere but couldn't remember where, It should work though (unlike everything else in the crapbook)

<small>[ September 30, 2002, 10:35 PM: Message edited by: xyz ]</small>

[Chris Shiherlis]

For remote controlled detonations which need exact timing I would recommend a very long wire and a switch :) .
For radio controlled detonation you can use all those devices mentioned before: beepers, mobile phones, DTMF transceivers, etc. It's quite easy to attach a relay.
But building a RELIABLE and SAFE RC-system with those devices is complicated. Since there's explosives attached to them you want a device that can ONLY be activated by YOU at the RIGHT moment and with 100% safety (you know what 99% safety in this case means don't you? :) ).
And relays attached to speakers or the vibrating motor of mobile phones and beepers is certainly not 100% safe: someone else calling the wrong number, unwanted SMS advertisement messages, the phone beeping when it's turned on or batteries are low, etc.
And other drawbacks are: they don't respond immediately, and mobile phones are just disguised tracking devices.
So to make it work you need a lot of circuitry. Just as with the DTMF system (but if you know some about electronics and want to use the DTMF system, go to : <a href="http://www.boondog.com" target="_blank">www.boondog.com</a> and click on 'tutorials' and then on DTMF decoder for the schematics).

So XOO for an easy and very reliable RC system just buy a 2 canal RC carsystem with transmitter, receiver and two servo's and a battery pack. Also buy 3 LED's and resistors (10 Kohm) and 2 microswitches.

Then you glue the microswitches to the side of the 2 servo's so that they can be closed by the servo at the maximum position by your transmitter.
Then you attach the switches in series with the battery, so when they both are closed the circuitry is closed and your blasting cap is ignited. You use the LED's to see if the switches are closed or open and one LED for seeing if the receiver is turned on.

This way you get an easy and (almost :) )100% safe RC detonation device: turn on the transmitter and receiver (power check LED will light up) and check if there are any disturbing radiosignals (which is of course possible because there are a lot of RC cars around!), if so, the servo's will move maybe even closing the switches (and lighting the LED's). If someone else is playing around just tell him it's better to wander off :) (he will always be closeby because those transmitters don't have a great range).
You can also switch to another frequency (preferably to a very uncommon exotic one) by using a different crystal.
When it's SAFE you attach your detonator while watching the LED's. And then move away. Then at the right time you close the first switch (LED lights up). The system is activated now and will respond immediately when you close the second switch (another LED lights up). So only when YOU want it, the thing goes BOOM!
Hopefully this is of any use to you.

This system has also the advantage that you can attach detonators that need a lot of current e.g. because Nichrom wire is used, without needing extra batteries.

Of course 100% safety is impossible for any device, but I think you get close with this one (even if there is someone playing around with with his car at the same frequency, the chances both switches are closed is low: they close only if BOTH the joysticks on the transmitter are at the right MAXIMUM position at the SAME time. And with two joysticks you have 4 positions. Well it's a bit difficult to explain but even then it's reasonably safe but I would recommend using another frequency :) ).

<small>[ October 05, 2002, 07:10 AM: Message edited by: Chris Shiherlis ]</small>

[Fl4PP4W0k]

Meh... Some good ideas.
I dont like the idea of a poor beeper or cellphone being blown to bits though :)

I have a handheld radio. Fun little toy. Modified for a huge transmission range. Something like 108-177 and 400-500 useable.
It also has a built in memory DTMF encoder. You pre-program an upto 12 tone DTMF sequence, and at the touch of a button it is sent to whatever frequencie. Handy.

Also, I used to have a DTMF decoder relay (for answering machines, you placed it next to the speaker and it would activate a 12v relay to turn shit on). About $15 i think. Only a 4 digit, but hey.
I replaced the mike with a 3.5mm lead, that could plug into the earphone of any radio.
You know those dirt cheap FRS peices of junk? Cheap shit. You can plug this decoder into one of those.
Heres a mid priced set... <a href="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1386698633" target="_blank">http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1386698633</a> so about $15 max each.
I have seen cheaper ones for about $10 each, with no screen and only 2 channels.

The $15 each ones are better, as you can add a 'Security' code, which is actually a CTCSS squelch code. Eg: Smaller chance that some lame ass lost kid at a mall will use your channel.

Sooo... Hook up 4 AA batteries to the relay, and a small rocket igniter to the output. I find the higher amperage of AA's makes igniters more reliable. Or use a 6v lantern battery and a home made igniter.
Ok. Tune your handheld radio to that frequencie. Key in the CTCSS code and get ready to rumble :D
Press the DTMF preset and BLAMMO! Im sure you can buy a DTMF decoder that will let you set off separate relays from different codes.
Distance is only limited to your transmitter. A mobile one (in a car)@ about 25w could easily det. one of those things from 10 or 15 miles.

Overall, its allot cheaper than a cellphone \ pager setup, Simpler to construct, and more convenient IMHO -
Theres no need to worry about accidental detonation either, especially in Australia as those FRS radios arent used here :)

CTCSS code + DTMF is VERY reliable.

[Jumala]

I´m reading now a book about direkt conversion receivers. This receivers are very simple. Only one BF 961 Dual Gate Mosfet and some other parts. It works at 430 MHz without antenna. A half turn of copperwire is resonant circruit and antenna. Only adjusting the receiver is a problem without HF equipment.
In combination with DTMF it could be a good possibility.
I will build one for testing next days.
Some garage door opener use this receivers too.

[Fl4PP4W0k]

You can purchase these little receivers quite cheaply, pre built. About $15AU which is roughly $8US.
Im not sure what equipment is required to make them USEABLE for remote detonation, but the ones I have seen are purely digital.
Im guessing a garage door opener style digital code would be do-able. Just means more hassle than the analog DTMF transmitter \ receiver.

Although, if implemented well - this could be a very cheap and effective alternative.

[zeocrash]

ok right, the other day i saw a remote control doorbell, so that your doorbell can move around the house and garden with you. i was ondering if you could remove the bell mechanism and attach it to an ignitor, and use it as an rc (no pun meant) detonator.
i would guess it is fairly safe as it has a range of about 100 m, and they have been designed so that they dont go off accidently, otherwise you would have a phantom doorbell. any ideas

[darkdontay]

Yes, but their is allways things you want to consider before ever trying something like that.. What is the channel and is their traffic on that channel in your area. Is thier any filter it goes though, I mean is it sensitive to interfernce...