I need to build a sequencer to electronically fire fireworks. I have built a couple of different designs, but they didn't work real well. So I thought I would come to the experts for some help. After some searching I found this design and I thought I would use it to drive some TIP122's and run 24v though it. Any suggestions.

 

A slightly simpler ckt is: http://forum.allaboutcircuits.com/attachment.php?attachmentid=5816&d=1228883204

I would use a PNP , like TIP225 ??,for the switch. What is current load? How many switches do you really need?

 

A slightly simpler ckt is: http://forum.allaboutcircuits.com/attachment.php?attachmentid=5816&d=1228883204

I would use a PNP , like TIP225 ??,for the switch. What is current load? How many switches do you really need?

See thats why I came here for help. This is an example of a e-match that we use. I would like to get around the 20 someting in switches.

Resistance
Maximum No-Fire Current
Minimum All-Fire Current
Recommended Min. Firing Current
Recommended Nominal Firing Current
Maximum Test Current
J-Tek
1 ohm
± .2 ohms
.30 amp.
.75 amp.
1.00 amp.
1.25 amp.
.04 amp.​

 

Something like this. Should be able to fire several squibs in parallel, along with the other 19.Quite a display.
Add a 10k from +24V to NPN collector to take care of leakage.

 

A slightly simpler ckt is: http://forum.allaboutcircuits.com/attachment.php?attachmentid=5816&d=1228883204

I would use a PNP , like TIP225 ??,for the switch. What is current load? How many switches do you really need?

BTW you did mean TIP125 didn't you.

 

TIP 125 it is, garbled NTE 262 with TIP 125

 

A slightly simpler ckt is: http://forum.allaboutcircuits.com/attachment.php?attachmentid=5816&d=1228883204

I would use a PNP , like TIP225 ??,for the switch. What is current load? How many switches do you really need?

You do realize they are the same circuit? Except I used diodes for AND gates and added LEDs w/ transistor drivers.

Something I've seen the pro's use on TV is a bed of nails. You nail a series of nails into a board with wires attached going to the igniters and a contacter wiper that is hot. Simply wipe the contacter across the nails in sequence and you get the same effect with a lot less effort.

 

You do realize they are the same circuit? Except I used diodes for AND gates and added LEDs w/ transistor drivers.

Something I've seen the pro's use on TV is a bed of nails. You nail a series of nails into a board with wires attached going to the igniters and a contacter wiper that is hot. Simply wipe the contacter across the nails in sequence and you get the same effect with a lot less effort.

It's a lot easyer to use a sequencer, it gives you exact times between shells. sometime you use about .25 seconds between shels to give a good efect. For the big shows it's computer fired.

BTW thanks guys for the help your all great.

 

This is an example of how to start other ones but this won't work for me, any idea's.

 

What is the voltage and current you want to use for the igniter? How many fireworks do you want to fire?

The original schematic you showed (which I drew) is good for around 100ma, and with a little modification it can be good for an amp. Since each transistor is a switch to ground it doesn't really matter what your voltage is.

I'm also assuming everything is battery operated, is it?

 

To start sequencer, I would have 3 switches, 1-logic power, 2- 555 reset, 3- TIP122 emitter power. Also Output monitoring LEDs fed from logic power. Switching on logic power should also reset all 4017s. With a clear board, SW-3 can be closed, When ready- open SW 2, & clock is started. Three 4017 should provide up to 25 outputs. 12V should supply a minimum of 1.25A with max. of 7Ω of firing line resistance.
Need PNP= TIP125

 

What is the voltage and current you want to use for the igniter? How many fireworks do you want to fire?

The original schematic you showed (which I drew) is good for around 100ma, and with a little modification it can be good for an amp. Since each transistor is a switch to ground it doesn't really matter what your voltage is.

I'm also assuming everything is battery operated, is it?

I will be using 2 voltage bus's one at 12v and one at 24v with a common ground. I only want to be able to fire a couple e-matches at one time on each cue, but the ones that I have used in the past were so under powered that they would blow the firing transisters all the time. i will also build something in case of a direct short. Using the tip 125 for firing I think that will be plenty. But you guys are the experts, I am just a very novice person.

 

With 24V firing V , could add up to 5Ω in collector ckt in addition to firing line & cap resistance & still supply 2.5A firing current, while offering short ckt. protection.

 

Ok this is the one That I came up with, does anybody see any changes that I need to make before PCB Layout. I know it takes me a long time.

 

That should provide 24v to your eMatches. Every clock pulse should light another eMatch and continue down the line.

You can test this with automotive style light bulbs before attaching the final fireworks.

You may want to consider a safety switch also.

 

That should provide 24v to your eMatches. Every clock pulse should light another eMatch and continue down the line.

You can test this with automotive style light bulbs before attaching the final fireworks.

You may want to consider a safety switch also.

After I get this working I will be adding a saftey switch, but I still haven't even built the way to start it yet. hehe

 

I believe there are several problems: 555-pin 6 & 2 should be tied together, pin 7 no connection? Add cap bypass to p-5,.1uF? Add 10k between p-4 & +12V to that a NC SW can hold 555 at reset. 4017: one output will always be high, at reset it is p-3, D00, so shift all output lines down one place. D09 will remain hot untill after last shot unless provision to reset 4017 & 555 is made.Possibly could invert D09 & triggrr another 555 which then would be used as input to Q17. Now connect 555-4 to 4017-15 via invertor. Could connect R36-R34 to +12V so ckt. could be monitored before applying +24V.
Small side note: Between 1950& 1960 , working in seismic oil exploration, we blew up many tons of explosives, with blasts timed to fire on 1/10 sec lines of oscillographs, equipment designed & built by Bernard.

 

Actually just connect pin 2 to pins 6 & 7, and ground pin 1, then it will oscillate. This is the circuit...

I would also add a cap for pin 5. While not totally necessary you want stability for this kind of application.

Source My Cookbook

 

Thanks Guys.