Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Newby looking for help with a Pyro/Fireworks Project

Status
Not open for further replies.

ru leisure

New Member
Newby looking for help with a Pyro Project

Hello, My name is Ian, aged 30, and im based just south of London, England.

A quick history, I studied to become a general electrician after leaving college. After qualifying I stupidly did not pursue electrics and spent the last 10 years on the technical side of running night clubs and bars, which Im now out of. As both the electrical regs and employers requirements have changed so much in the UK over the years I am now starting to re study for this. Basically I have an understanding of electricity and electrical safety, and as part of my training done a foundation in electronics, so know the basic basic basics of components, their functions and how to treat them with regards to assembly.

As a money earning day job during my studies im a maintenance / odd job man for a property company. However my real passion is pyrotechnics and I am a qualified pyrotechnician under the BPA (British Pyrotechnics Association)…Projects regarding this will be what I seek advice on.

Like most joining forums, im seeking your skilled advice, and eventually like the other forums I have joined over the years will one day be able to offer something back from my skills knowledge.

Ok, will blabbing intro over the questions…

Im looking to build two simple circuits

First and most important, a stepper circuit (not sure of the tech name – it will be explained) in pyro we call this “Step-Fire” or often seen on US info sites as “Trigger Fire”

One momentary push button switch on a firing desk will step fire through multiple channels on a remote (wired remote – pref minimal number of cores) field box. So, when I press the fire button on the desk first time it will send an electrical pulse and trigger channel one. Press it again to trigger channel two, and so on. It dose not matter if the previous channel(s) stay on as the igniters would have already burst and been left in a state of open circuit.

Iv had a quick play around with the Velleman K8023 kit (http://www.velleman.be/ot/en/product/view/?id=348779)
to replace its automated pulse with a push button with no joy.

Can any of you guys offer a circuit or links to a circuit to do such a simple step program.10 channels would have to be the lowest, ideally 20-30 would be great. Voltage would ideally be in the 12v range but my basic electronics will allow me to work with other values. The more power the better, although igniters/dets normally pop around 60mA we can often have several connected to one channel… again, I can overcome this part on my own.

The second circuit should be even easier, but again I have failed to succeed in my spec. I am looking to build a simple chase circuit. Again I purchased a Valleman kit as a base to start from. What im looking to achieve is a chase sequence which I can vary the time between steps using a variable voltages, such as a multi way rotary switch with different resistance vales on each position or a variable resistor (potentiometer). I have achieved success in doing this with one of the Valleman kits but only at 6 channels… I need to achieve 20+ channels in each chase unit!

Sorry for rambling on.

Any help would be greatly appreciated.

Ian (E)
 
What about computer control

here is a link to a christmas light project that would do everything you want plus control the pyro show to music.
https://www.doityourselfchristmas.com/forums/
I have built most all the electronic hardware and they all work great.
for about $100 you can have 64 channels computer controled.
do chase sequences, random, and all to music.
this would be easier than using several kits that don't work as desired.
sure its Christmas oriented but why not pyrotechnics as well??
 
Hi, (sorry forgot the name)

How about this?

A decimal counter (CD4017) can be programmed (wire programmed) to any number to either stop or recycle. You can cascade and/or parallel as many as you want and have 10 outputs per chip. (paralleling for simultaneous firing and cascading for step firing)

Using a continuous clock signal at its input you can not only "step fire" but also "ripple fire" and have it stop where you want, either resetting the chip or inhibiting clock input.

100US$ is quite a lot of money. A CD4017 costs 17Cents (including sales tax).
Obtain a data sheet at ST (type name at ST is HCF4017) and you'll get what I guess you need.

I sometimes don't have the understanding that people reach for an MCU solution so quickly. If the projects get more complex you might want to use an MCU, but for a simple task like step firing that counter is almost perfect, not to forget - cheap.

Regards

Hans
 
Thank you both for your posts so far. Intresting to see two ways, and amazed to see how big the US Christmas lighting industry is… It just seems to be blow up snow men and static xmas light here in the UK.

MrDeb, although the link was very interesting, all the projects seemed to be PC controlled (I may be missing a particular post though). These seem to be where Merlin Match Fire (very good system) have created their system from as the diagrams are almost identical. This is something I will be experimenting with further down the line.

Boncuk. A 4017 based sequencer is something iv already toyed with, using a project kit and now a better understanding after looking at Kinjalgp’s post and diagram (https://www.electro-tech-online.com/threads/10-channel-light-bulb-sequencer.327/ ). The original idea was to be able to interrupt the feed from the 555 and control the stepping with my old push button switch (step fire). And reengage the 555 to work as a triggered auto chase sequences. However what I don’t understand is how to cascade these as you mentioned to increase the number of channels?

“Obtain a data sheet at ST”… Sorry, what is ST?

Many thanks again.

Any one else?

Ian:)
 
Fireworks

Hi Ian,

ST stands for SGS-Thomson after SGS and Thomson had fusioned. Just use ST for the URL: https://www.st.com

Search for part number HCF4017 and you can download the data sheet.

Cascading decimal counters can be done using two methods: Either use the 'carry out' pin or simply connect the last count output to the clock input of the following stage.

You are free to select either manual or automatic (timed clock pulses for the counter) or use both by toggling the function.

A while ago I made a similar circuit for a model rocketeer, but since rockets are usually more expensive (at least the high power rockets) than fireworks I limited sequencing to a maximum of five, which you can use for your application too by either stopping the counter at the desired count or resetting it. Stopping the counter at any position means to employ a ten position switch to select either output.

Hans
 
I can supply you with a simple circuit that was built 20 years ago, and continues to delight passersby. Originally for Christmas lights, it can be adapted for your needs.
 

Attachments

  • xmaslights.gif
    xmaslights.gif
    71.5 KB · Views: 750
Hi Ian,

I thought about cascading decimal counters of the type CD4017 and came to the conclusion that it can't be done just by wiring an output of one to the clock input of the follow on stage. That way the second counter would only advance by one if the preceeding has counted through 10, meaning the second stage would be clocked at 1/10 of the original frequency.

To overcome this problem an analog multiplexer can be used. I made up a small sample circuit showing the idea.

Inputs A,B, and C are binary coded inputs switching the common input to one of the outputs X0 through X7. All inputs low means X0 is active, input A = H means output X1 is active. To activate X7 all three inputs A,B and C have to be high.

The sample circuit does not include a logic coder to activate any desired output. If A and B inputs are high output X3 will be active. To have output X2 activated, input A requires turn off which can be accomplished by a coder circuit.

Anyway, the complete circuit lets you count from zero to 79 at the same time intervals.

Hans
 

Attachments

  • 4017-SEQUENCER.jpg
    4017-SEQUENCER.jpg
    123.6 KB · Views: 2,088
The computer xmas circuit can be cheaper

the major cost is all the SSR's (solid state relays)
a used computer can be had very cheap ass well. Win 98 will work.
the major advantage to using the computer xmas circuit is a bigger varity of patterns could be utilized and cordinated to music.
Your pyro display would stand out from the norm.
For $100 (fewer SSR's, a used computer, control board)
NOTE if you can fire the fireworks with 5VDC then the SSR's could be left out.
The control board uses a ULN2803 as the outputs
Sure the 4017 circuits are good but think outside the box.
 
Hi MrDEB,

I guess the OP isn't much interested in coordinating firing of rockets or fire crackers with music.

He just wants to sequentially fire as many as possible with the option of automatic ripple fire.

Firing e.g. 60 rockets in sequence also means a separate ignition circuit each.
That Xmas thing certainly doesn't fire one light at a time, so reprogramming will be necessary and I also doubt it has 60 independent output channels. With an encoder around the decimal counters and the multiplexer he can fire as many as 80 rockets, all in sequence.

I also don't know the conditions he must build up the pryotechnic devices and if he will have AC power for a computer (PC).

Initiation of ignition will not take much voltage, but high current for a short time. I used to fire my model rockets using a 2V lead acid battery rated 55Ah. That was a bit too strong, but I had to charge it just once within six months. To switch on the ignition circuit he just has to connect medium power switching transistors to each output and he'll be done. SSRs point pretty much towards AC powered incandescent lamps and so they may be skipped.

Now, let's get the OP's opinion about it.

Regards

Hans
 
Guys, I really do appreciate both your inputs. It is helping me learn so much!

For this project (unless anyone come up with something else) im having to swing towards the 4017.

My starting spec was : to build a remote field box with its own 12v supply, capable of step firing between channels using only one channel (momentary push switch) in the desk using only a 2 core flex. Using a selectable separate pulse switch circuit able to hold a 555 timer on to then ripple fire, making the unit(s) available to be used as manual controllers and chase sequencers.

Trigger cable is a major factor in this. There are already loads of systems that use network cable and multi core cables, iv built and used these in the past… from experience these tend to push the initial and running costs up considerably. The pyro site is a hectic environment with lots of heavy steel work, so cable often get damaged. With a two core flex its easy to do a quick repair or swap a cable out. This is a key selling point of the worlds leading FireOne system… unfortunately these cost £10k+ and are far too advanced for my current needs.

Unfortunately most firework displays are set up at the end of a field or back of a golf club where there is no power, so everything has to have its own internal power supply, even the control desk. I have in the past been able to fire 3 igniters from a domestic AAA battery so output power is minor, I believe the required ignition current is around 50ma.

Just for information… All the worth while professional pyrotechnics associations around the world recommend the excessive use of diodes – if a part of a circuit needs one, then fit two, on both + & -. At the end of the day there are explosives on the end of that lead… I find a fresh circuit as recommended in the 4017 is easier to incorporate this request. It is also frowned apon in the industry to use relays. There have been many experiments testing some ‘cheap’ systems that use relays with worrying findings. As a pyrotechnican my main interest is safety. Unfortunately on occasions out of our control things go wrong and with our numerous safety procedures such ‘misfires’ occur and are contained to the firing area. These include ‘flowerpots’ (where a shell bursts in the tube) and low brakes (where a shell fails to rise properly or a faulty lift delay fuse causes it to burst too low). Remember these are not consumer fireworks, shells can contain between 1-8kg of high quality flash powder. In the tests most of the system using relays activated other channels if not all due the the massive shock moving the contactors… the last thing a pyro needs is more going off when he/she needs to asses the situation.

Again, I like the idea of building a pc based system one day in the future, but for the pyro musical displays I have access to a MLE Fire-By-Wire system. In the mean time I just need flexible multi use modules capable of the two basic functions above.
 
Fireworks

Hi Ian,

cascading CD4017 is much simpler using AND-gates. That way you might have hundreds of sequenced outputs.

For manual clocking use a debounced key and for automatic clocking use an NE555 timer circuit with variable frequency output.

This is how cascading works.

Hans
 

Attachments

  • Cascade.jpg
    Cascade.jpg
    118.7 KB · Views: 1,111
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top