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How do you make a Failsafe Arming Circuit?

RovertScott

Overview:

I need a circuit that will alow me to safely arm and detonate fireworks for an upcoming filming project.

 

Operation:

0. A firework has Detonation Wires inserted and the ends are wrapped around exposed screws attached to a Detonation Circuit

1. Activating a light up Master Switch provides power to six circuits for detonating fireworks via four D batteries

2. When the Master Switch is activated a Yellow LED blinks as a capacitor is charged.

3. Once the Capacitor is charged the Yellow LED turns off and a Green LED turns on.

4. Switching a Toggle Switch causes the Green LED to turn off and a Red LED to turn on (It's Armed).

     During this time the firework's Detonatioin Wire Contacts are connected to the Detonation Circuit (Mechanical/Electrical Fail Safe)

5. Upon pressing a large Red Firing Button the capacitor is discharged through the Detonation Contacts to the wires and into the firework.

6. The Capacitor will not charge again until the Toggle Switch is placed back into the default unarmed position.

 

and (If any capacitors are charged when attempting to shut down)

 

7. Before the Master Switch can be switched off Two Purge Arm Toggle Switches must be flipped (All other LEDs turn off and all Red LEDs turn on)

8. Pressing the Purge Button will discharge all the capacitors one after the other into a ground wire until all capacitors are empty (After discharge Red LED turns off)

     Now unless the Two Toggle Switches are Reset the Capacitors won't start charging again and all LEDs will remain off

8. Now the Master Switch can be turned off and all flipped Toggle Switches can be reset.

 

The Specs:


MISC

x1 Master Switch

x4 D Batteries

 

DETONATION CIRCUITS (x6)

x1 Toggle Switch

x1 Firing Button

x1 Capacitor

x2 Detonation Wire Contacts

x3 LEDs (RGY)

 

PURGE CIRCUIT

x1 Insulated Ground Wire Contact

x1 Purge Button

x2 Toggle Switched

Attachments:
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  • You will need a very big capacitator to get a big enough jolt and probably you will also need about 20-25awg wire should be good enough.  As for hooking it up you need to route the batteries to the main power then to the toggle switch then to the capacitator the to another switch that will fire then back to the batteries.  You will need the two wires coming out of the box to attach to your firework.  I would get a hobby box from radioshack and a battery holder as well then get a fighter piolt switch, flip switch, and a push button switch.  So basically you turn a flip switch on to turn the device on then arm the capacitator by flipping the fighter piolt switch.  Finally you need to hold the tact or momentary switch down to actually send the energy to the fireworks.  If that is confusing just post here and I will get back to you ASAP!  Sounds like a good idea for safely letting children shoot fireworks off on the 4th of july and new years.  And I know I changed you plans up a little but In my opinion this is the simpleist way to do it while still providing safety.

  • After further examing you drawing I realize my previous post has some flaws.  You would need to do all of that and then add in your 6 chambers for firing if that makes sense.  I am working on a drawing for you and a basic parts list I will upload later. 

  • in reply to killarshark33

    Thanks for the help, I really appreciate it. If the whole light system and purge thing is just way too complicated, then just forget it. The ability to charge and safley disharge multiple capacitors inorder to detonate fireworks is my main concern.

  • in reply to RovertScott

    Yeah the leds would not be hard to install in the circut but you are going to have to get resistors because 4 d batteries will probablly burn out an led, however I am not sure if it will.