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Electrical Firing System


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#31 BigG

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Posted 24 September 2004 - 12:33 PM

BigG,
Where can I find Electrical firing systems issue in this forum.
Thank you

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I have merged the existing topics on the subject. They are now all under one thread. Please do not start any new threads regarding firing systems.

#32 KingVinny

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Posted 24 September 2004 - 01:11 PM

Thanks BigG I'll look harder next time I start a thread
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#33 pyrotechnist

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Posted 26 September 2004 - 04:01 PM

Is it me your talking about BigG or KingVinny? I made this topic ages ago now lol. Also i have made a cicuit diagram of my firing system but it is not yet finished lots to do but it basicly works. I have been working hard on the testing and am wondering how you lot make a testing unit that tests all the cables and stuff? I have made one but am wondering if i can make an easy one mine is basicly one LED that works off the main power but the voltage gets lowerd and the output voltage is very small aswell so it is ok. It will when a brake accurse will stop the LED from working so it will not light up it works and if i brake one that one dosn't work and the rest will and it tests the whole system :) . But what type of battery will i need for a 25 shot firing system going to 2 slave boxes? I am also wondering were you get NiChrome wire from? Also does anyone know if you can get 25 pin switches? Thanks.
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#34 Arthur Brown

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Posted 26 September 2004 - 09:43 PM

Go back a few posts the info is there. The TEST cct should be constant current at well below 20mA the FIRE cct needs about 1.5v per fuse both using commercial igniters. Dodgy home brew igniters are not advised as you will never make enough the same to do the tests and statistics to test the all sure fire current and the all sure not fire current. Buy 'em 36p to ?1 each I'm told.
The use of low voltage capacitor discharge (typ 18v ) just improves the source resistance, the use of HV cap discharge (400 - 800v ) is to allow the use of VERY long wires when firing big bangs (ordnance disposal etc)
Look for Eureaka wire - solders better than nichrome. 36swg or finer.
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Keep mannequins and watermelons away from fireworks..they always get hurt..

#35 ChesterPFX

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Posted 27 September 2004 - 09:58 PM

My newest system has 36 cues going to six breakout boxes with 6 terminals each. To test them, I just fitted 6 led's into the side of a small enclosure with the wires coming out the other side. I soldered on test plugs to the end. Once the panel, power, cables and boxes are all attached I start at the first box and plug in the 6 Led's into the 6 terminals. I then test each cicuit, seeing if the Led lights at the touch of the corresponding button. This also means that if there is a short within that local circuit, the Led on the channel that is shorting will also light up.

#36 pyrotechnist

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Posted 29 September 2004 - 05:42 PM

Thanks i used for my test i don't know if this is ok but pleas advice me if not. I used one LED which is connected to the main cable going to the slave box and thru that circuit if the circuit is brok on that certain cue the LED won't light up and so it will indicate there is a fault there. I just add the - negative side to the cue so when i take a wire away or out that one cue is not a full circuit and cause the LED is using that it won't work neither. It works perfect to on each and every cue also the output is very low from the LED and 1k resistor. Does this sound good or am i doing it wrong? Thanks.

Edited by pyrotechnist, 29 September 2004 - 05:44 PM.

fireworks is my aim setting of is the game

#37 Arthur Brown

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Posted 02 October 2004 - 05:20 PM

Has anyone used a Le Maitre battery powered controller?
http://www.movember.com/uk/home/

Keep mannequins and watermelons away from fireworks..they always get hurt..

#38 KingVinny

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Posted 07 October 2004 - 07:58 PM

I've just started making my firing system. I have five 9v duracell procell batteries and have linked them all together. Will this be enough to heat some nichrome wire up suffeciently to ignite a dark flash ignition paste? Or will I need to add some capacitors to send a sudden high voltage shock down the wire?
Go hard and play safe!!!

#39 Arthur Brown

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Posted 07 October 2004 - 08:11 PM

It is most important that the firing cct is of proven quality. As you will see in Helmetfire's post ( in rocketry) a pyro igniter has a resistance of about 1.4 ohms a no fire current of 20 mA and an all fire current of 500mA Then you must measure the resistance of the command wire and using ohm's law find the V required to get a firing current through a known resistance, then check that the supply will actually give that current. Dry batteries are not good at big loads, thats why people use capacitors
http://www.movember.com/uk/home/

Keep mannequins and watermelons away from fireworks..they always get hurt..

#40 BigG

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Posted 07 October 2004 - 08:23 PM

I've just started making my firing system.? I have five 9v duracell procell batteries and have linked them all together.? Will this be enough to heat some nichrome wire up suffeciently to ignite a dark flash ignition paste?? Or will I need to add some capacitors to send a sudden high voltage shock down the wire?

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If your nicrome wire is thin enough - it will be enough. Estate ignites thiers using 6V. The only thing you might find as a problem is you dark flash paste. Why not use BP? Safer and ignite at a much lower temp.

Edited by BigG, 07 October 2004 - 08:25 PM.


#41 pyrotechnist

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Posted 29 January 2005 - 10:07 PM

Hi i have not posted for awhile i have been bussie. I am doing ok now on my circuit but can you lot pleas check to see if it good or not? Also does every firing system need a Copacitor to increas the voltage supply to the Egniter?

My circuit diagram pleas see if it is ok.
http://uk.pg.photos....album?.dir=97cd

Pleas give me feedback on anything that is wrong or needs changing :) . My electronics teacher likes it but he says it is to much electrical and not electronic. What am i soposed to do to make it more electronic? I have tried a PIC chip so i could program the firing system and i got it to switch on the Bulb representing a firework and then turn off so it will wait turn on then off. But that didn't like the Diodes for some reason.
fireworks is my aim setting of is the game

#42 Flashy

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Posted 29 January 2005 - 10:17 PM

Only had a very quick look, i'm assuming the two switches directly after the power supply are the arming switches? if so they should be normally open switches not normally closed as shown on the diagram. I will have another look when i'm not so tired, what do the red flags represent?

the area below seems to be incomplete, if this is intentional the diagram should be labelled accordingly.

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I'm guessing now that the other two switches are to allow for more firing points meaning that you could have 90 cues in total? In affect there would be 3 circuits each having 30 cues, altough you have a lamp indicating which circuit isactive it may be a good idea to include an indicator to show which row is selected just for ease of use. If you want to make the system more electronic you could add in a timer circuit. This could act like a sophisticated nail board for setting off a rack of rockets or mortars. This may please your electronics teacher.

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Edited by Flashy, 29 January 2005 - 10:46 PM.


#43 ProfHawking

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Posted 31 January 2005 - 07:20 PM

I've been working on a digital firing system. It uses cat5 cable. I'm aware of its limits regarding strengh and reliability, so would be using the outdoor armoured type.
The current carrying ability is aided by using a power storage capacator at the end box, which will allow higher currents for a short enough time to light the ematch being triggered.
The design has a low current connection checker, and at the moment supports 8 devices, although using BCD encoded signals on the 3 selection wires, up to 16 devices could be supported.

So far, my schematic is this one: http://highspeed1.cl....uk/firesys.jpg

Anyone got any suggestions/tips?

Edited by ProfHawking, 01 February 2005 - 01:28 PM.


#44 pyrotechnist

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Posted 01 February 2005 - 06:01 PM

Wow thanks Flashy. But were would i integrate that into my circuit or how could i use it? The red flags are the ammount of voltage going thru the circuit. I intentionaly left them other two row selectors out due to the size of the circuit. Also what is the 4017? is this a chip or just a wire arrangement?

Edited by pyrotechnist, 01 February 2005 - 08:20 PM.

fireworks is my aim setting of is the game

#45 Flashy

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Posted 01 February 2005 - 06:45 PM

Wow thanks Flashy. But were would i integrate that into my circuit or how could i use it? The red flags are the ammount of voltage going thru the circuit. I intentionaly left them other two row selectors out due to the size of the circuit.

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You could add another bank of switches, one to select the timing circuit, which would be the arm switch and a one to supply power to the circuit which would be the fire switch. You would need a resistor to bring down the voltage to the circuit. For the output from the timing circuit you would need to replace the leds labelled 1 to 10 with relays, as the output from the timer will not be powerfull enough to set off an ematch. And if the timer steps too quickly through its outputs it may not leave enough time for the ematch to ignite. The time between each output can be configured by changing the values of the 47K resistor and the 1uF capacitor.

With the indicator lamps on the row selectors, are the lamps to indicate that the circuit is safe or armed? At the moment they would show which circuits were safe (green?), you could add a lamp into each of the circuits to show which one was armed (red?). At the moment the lamp is being switched from the negative side, it should really be switched from the positive side, this only means changing two connections, the side of the bulb which is not connected to the switch should go to the negative and the positive should go to the switch. This doesn't make a difference in this circuit, but if your interested in electrical work and electronics its always good practice.




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