Firework ignitor using mosfets and led matrix

[john6v54]

Hello, this project builds off the the work done here:

https://www.electro-tech-online.com/threads/electronic-firing-system-for-fireworks.21046/

My goal is to use a microcontroller to control the firing of a large number of cues. The exact number isn't important, but at least 64 would be preferred.

I'd like to replace the pushbuttons in the following schematic with mosfets.


The image is by eblc1388 and taken from the thread referenced above. I apologize if I should not have posted the image here. Please let me know if I need to remove it.

The mosfets would be controlled by an led matrix; for example: this or this. The mosfets would replace the leds in the matrix.

Is this feasible? Is there a better way to do it?

Each cue would require 1-2 amps for a few seconds max. Several cues may be fired immediately in succession or there may be a pause of several seconds between firings.

Thank you in advance for all of your help.

 

[alec_t]

The mosfets would replace the leds in the matrix.

Not clear how you'd do that. The LEDs are 2-pin devices whereas the FETs are 3-pin

 

[4pyros]

Is this feasible? Is there a better way to do it?

That was a manual fire system. If you want computer control you need to start over.

Do to the fact that fireforks can kill you if you dont know what you are doing! I dont think you should be doing this!

 

[canadaelk]

I designed this thing (attached) on spec a while back. It is uP controlled and multiple units can be connected to each other (the box, not the cat!). It still needs some work, PM me if you have any interest in it. E

 

[4pyros]

I designed this thing (attached) on spec a while back. It is uP controlled and multiple units can be connected to each other (the box, not the cat!). It still needs some work, PM me if you have any interest in it. E

Thats interesting. The box, not the cat. How many ques can it control?

 

[canadaelk]

8 each Pyromate. When you look at the pix you will see "Expand" I/O connectors to add more units. I have to look at the code, but I know at least 8 boxes
From what I recall there is a bit of pcb work left to do. The unit was tested and it works. E

 

[4pyros]

Pyromate is the name of another fireing system maker;

https://www.pyromate.com/

 

[canadaelk]

Thanks! Well, I am not a manufacturer of this type of equipment, just picked the name out of the blue. I"ll rename it "The Box 101" so I won't get sued by big biz. E

 

[4pyros]

Looks like a sequncer?

 

[WTP Pepper]

I would keep a physical switch to arm/disarm all fireworks. I would also charge a large capacitor for each firework and discharge that into the firework on cue.
Controlling 64 is easy from a micro. Use a series of shift registers to create a 3 wire port expander.
I can rustle up a basic circuit for one if needed.

 

[tcmtech]

My brother is into fireworks big time, **broken link removed** , and he uses a relay output based control system being relays are next to impossible to trigger with a stray static discharge event that would normally turn or even short a FET based output to full on plus the mechanincal contacts in a relay are far more forgiving to the occasional short circuits that happen in output lines as well.


So do you really want a firing system that could conceivably launch a 4" salute or worse into you or soeone elses face while out checking something for some other reason in that 1 in a 100 times you thought that the main power was off off but wasn't just because your cat brushed up against a wire someplace?

 

[4pyros]

Once again people that don't know what thay are doing can get killed by fireworks.

 

[4pyros]

My brother is into fireworks big time, **broken link removed** , and he uses a relay output based control system being relays are next to impossible to trigger with a stray static discharge event that would normally turn or even short a FET based output to full on plus the mechanincal contacts in a relay are far more forgiving to the occasional short circuits that happen in output lines as well.


So do you really want a firing system that could conceivably launch a 4" salute or worse into you or soeone elses face while out checking something for some other reason in that 1 in a 100 times you thought that the main power was off off but wasn't just because your cat brushed up against a wire someplace?

A 4" salute could bounce all the relays in a box and fire all the fireworks connected. Never use relays around fireworks.

 

[tcmtech]

Why would you be setting off a salute at ground level next to your control system or mounting improperly protected/shielded firing boards that close to your launching tube systems in the first place?

If thats going on you already have far bigger safety issues to deal with including the local ATF and sheriffs dept!

BTW my brothers system gets fully inspected every year by the ATF and his designs have been found to be more than adequate for overall system safety and redundancy in applied usage.
He wouldn't have a pyrotechnics license if it didn't pass every inspection by them.

You don't get to his level and safety record by building half assed junk.

Never use relays around fireworks.

You may want to run that passed the forums here, https://www.amateurpyro.com/forums/ , where the big boys play and see what they are running on there electronically controled firing systems.

 

[4pyros]

Why would you be setting off a salute at ground level next to your control system or mounting improperly protected/shielded firing boards that close to your launching tube systems in the first place?

If thats going on you already have far bigger safety issues to deal with including the local ATF and sheriffs dept!

BTW my brothers system gets fully inspected every year by the ATF and his designs have been found to be more than adequate for overall system safety and redundancy in applied usage.
He wouldn't have a pyrotechnics license if it didn't pass every inspection by them.

You don't get to his level and safety record by building half assed junk.

Have you heard of a low brake?

We stopped using relays years ago.

No offence but maybe your brother should too.

 

[tcmtech]

Take it up with him. I just watch the show.

 

[john6v54]

I would keep a physical switch to arm/disarm all fireworks. I would also charge a large capacitor for each firework and discharge that into the firework on cue.

Physical switch, in addition to other safety features are a must. Here I'm just focusing on getting the cues to fire. My concern with capacitors is that they may have a charge and I wouldn't know it, thus setting off a cue accidentally. Or don't I need to worry about that?

Controlling 64 is easy from a micro. Use a series of shift registers to create a 3 wire port expander.
I can rustle up a basic circuit for one if needed.

Is there a way to control mosfets arranged in a grid using one shift register to control rows and another shift register to control columns?

Source and Drain of mosfets would be connected to 12v car battery.

As you can tell, I'm not very knowledgeable regarding electronics. I'm trying to get the concept worked out and learning what each piece of the puzzle is doing.

 

[john6v54]

So do you really want a firing system that could conceivably launch a 4" salute or worse into you or soeone elses face while out checking something for some other reason in that 1 in a 100 times you thought that the main power was off off but wasn't just because your cat brushed up against a wire someplace?

Safety implementation is a whole additional issue than what I'm trying to learn here. I believe there are many systems, including most commercial ones, that use solid state components, not relays.

 

[4pyros]

Do you want a sequencer?

 

[john6v54]

Do you want a sequencer?

I don't think so. I want complete control of when cues are fired. Will a sequencer fire the cues in a fixed succession? With a fixed time interval between each fire?