I suggested that in post#24. Even gave a link to Google that gave some circuits.

Oh I missed that, yes I'm sure that would do the job ok.

 

I HAVE BEEN WAITING FOR THE DUST TO SETTLE BEFORE I RESPONDED TO THE MANY INPUTS.

Hello ronv, We have had no feedback on your non-micro design proposal. I cannot see any holes in it. ronv, does your design tools generate a parts list. I am having some issues with MY ability to read the component numbers or types. Does anyone have a problem with his drivers for the solenoids or coil? I am going to build one of these and give it a shot. I believe that no matter what the design becomes, the driver circuits are critical.

Hello SgtWookie and all that have provided input for a mirco design. It seems the consensus is for a PIC of some kind and on a single PC board, SOLID, and environmentally protected. I am an OLD (30 years ago) designer and builder of micro based systems. It needs to have at a minimum of two A to D inputs, two digital inputs and two digital outputs.

For those who have proposed a Bird Scarer or Potato Gun circuit of some kind. This is not the same kind of animal. This one must be able to fire from 3 times a second to 5 minutes depending on the type of gun/cannon that your are trying to simulate. There are applications where it is only inches from your head...

Based on my OLD micro design experience, I am attaching a software flow chart:

 

I HAVE BEEN WAITING FOR THE DUST TO SETTLE BEFORE I RESPONDED TO THE MANY INPUTS.

Hello ronv, We have had no feedback on your non-micro design proposal. I cannot see any holes in it. ronv, does your design tools generate a parts list. I am having some issues with MY ability to read the component numbers or types. Does anyone have a problem with his drivers for the solenoids or coil? I am going to build one of these and give it a shot. I believe that no matter what the design becomes, the driver circuits are critical.

Hello SgtWookie and all that have provided input for a mirco design. It seems the consensus is for a PIC of some kind and on a single PC board, SOLID, and environmentally protected. I am an OLD (30 years ago) designer and builder of micro based systems. It needs to have at a minimum of two A to D inputs, two digital inputs and two digital outputs.

For those who have proposed a Bird Scarer or Potato Gun circuit of some kind. This is not the same kind of animal. This one must be able to fire from 3 times a second to 5 minutes depending on the type of gun/cannon that your are trying to simulate. There are applications where it is only inches from your head...

Based on my OLD micro design experience, I am attaching a software flow chart:View attachment 97824View attachment 97824

If your real nice I'll make you a parts list at Mouser, so all you need to do is click it and it will order the parts. I would use 556 IC's instead of 555s to save on the number of packages.
What test equipment do you have available? A scope? Will you do a PC board or a proto board?
I can post the .asc file from LtSpice and you can download LtSpice. Then you can open it on your computer so it will be easier to read.

 

If your real nice I'll make you a parts list at Mouser, so all you need to do is click it and it will order the parts. I would use 556 IC's instead of 555s to save on the number of packages.
What test equipment do you have available? A scope? Will you do a PC board or a proto board?
I can post the .asc file from LtSpice and you can download LtSpice. Then you can open it on your computer so it will be easier to read.

I am going to be sooooo sweet and nice that you can't refuse..... Thank you so much.

I still have a scope that works great and will use that. I am still pretty good with a soldering iron, getting old for that though. Yes, a couple of 556's are the way to go. I will use a proto/PC board of some kind? Even if a micro design follows some day, I will be able to verify the driver circuits. I have seen no feedback on any part of your design.

In my previous description I meant 5 seconds, not 5 minutes. We have some 5" 38 caliber guns that I hope to retrofit someday and their fire rate is around once every 5 seconds. The sailors of WW2 were a generation of Americans that we may never see again. To fire the 5" guns at that rate is just mind boggeling. If you ever get to the USS Alabama, I can show you what they had to do, and do it for hours. Amazing.

 

I am going to be sooooo sweet and nice that you can't refuse..... Thank you so much.

I still have a scope that works great and will use that. I am still pretty good with a soldering iron, getting old for that though. Yes, a couple of 556's are the way to go. I will use a proto/PC board of some kind? Even if a micro design follows some day, I will be able to verify the driver circuits. I have seen no feedback on any part of your design.

In my previous description I meant 5 seconds, not 5 minutes. We have some 5" 38 caliber guns that I hope to retrofit someday and their fire rate is around once every 5 seconds. The sailors of WW2 were a generation of Americans that we may never see again. To fire the 5" guns at that rate is just mind boggeling. If you ever get to the USS Alabama, I can show you what they had to do, and do it for hours. Amazing.

I noticed in your flow chart two sparks. Right now I only have one. Should I add another.
Sounds like you have all you need to build one.
How about the trigger? Do you have something already or do we need to find one that is suitable?
I'm pretty confident in everything except the spark circuit. I think it is okay but......
I guess we can test that first if no one comes to review it. I guess I could start a thread asking for review.
The grounding is another possible issue.
My son was on the Missouri during the first Gulf War. He took me on a tour. Hard work.

 

I noticed in your flow chart two sparks. Right now I only have one. Should I add another.
Sounds like you have all you need to build one.
How about the trigger? Do you have something already or do we need to find one that is suitable?
I'm pretty confident in everything except the spark circuit. I think it is okay but......
I guess we can test that first if no one comes to review it. I guess I could start a thread asking for review.
The grounding is another possible issue.
My son was on the Missouri during the first Gulf War. He took me on a tour. Hard work.

No, I think one spark should be good. Just added that as a future thought....
The trigger is simply a momentary NO push button on the trigger housing. My debounce is another future thought.
It would be nice if we did have some other reviews on the design..that is part of this forum... so why not?
Yes, we just have to make sure that all the grounds come to one location to avoid ground loops.

 

This is a very interesting project. We built several propane guns back in the '80's of various calibers and fire rates as part of a military-type demonstration for a theme park. If I can make a few suggestions: (I didn't read each and every post.)

- use two or more simultaneously fired spark plugs, each with its own coil;
- the pressurized oxygen is also from a cylinder (not ambient air,) as is the propane;
- add a third solenoid (especially on rapid fire simulators) to push VERY CLEAN, OIL & CONTAMINENT FREE compressed air through the barrel to blow out the burned gasses and to cool the barrel;
- if you have a lengthy burst of firings, consider investing in stainless steel barrels else you'll melt down!

It may interest readers to know the U.S. military developed training weapons using "propane" with tube-type controllers!! Fascinating stuff!!

Good luck and best wishes!

joe

 

This is a very interesting project. We built several propane guns back in the '80's of various calibers and fire rates as part of a military-type demonstration for a theme park. If I can make a few suggestions: (I didn't read each and every post.)

- use two or more simultaneously fired spark plugs, each with its own coil;
- the pressurized oxygen is also from a cylinder (not ambient air,) as is the propane;
- add a third solenoid (especially on rapid fire simulators) to push VERY CLEAN, OIL & CONTAMINENT FREE compressed air through the barrel to blow out the burned gasses and to cool the barrel;
- if you have a lengthy burst of firings, consider investing in stainless steel barrels else you'll melt down!

It may interest readers to know the U.S. military developed training weapons using "propane" with tube-type controllers!! Fascinating stuff!!

Good luck and best wishes!

joe

Thanks JoeFromOzarks, Very good info based on your experience. I will certainly try to incorporate some of your suggestions.

Another interesting thing is that most OLDER vehicle ignition systems did indeed fire two spark plugs at the same time from one coil. One on compression and one on exhaust on a 4 cycle engine.

Yes, My Uncle Jerry, who is an Army WW2 reenacter, has one of those original training weapons. It really does not look much like the weapon it is suppoed to simulate, but, it is what it is and his is not working at this time. Another project.

 

I thought that I would try thoughts from post # 25. I used a 3/4 in. brass check valve, 14 in. 3/4 in. iron pipe for barrel, input reduced to 1/4 in. to fit end of Burns- O- Matic torch. Several layers of screen wire & a layer of S-S cloth placed in valve input held tight by reducer as a flame suppressor. Body of valve drilled and tapped near output for 1/4 in. spark plug. Spark via neon sign transformer, relay, 555 giving 60 ms. relay closure & adjustable delay, 5/ sec. to 5 sec. / spark.. Torch adjusted for low slightly oxidizing flame, Tank valves closed torch re attached , spark off. Tank valves opened, spark on = very low put-put-put.. Slowed--- To be continued.

 

I was not watching my clock close enough.
Slowed firing rate to about 2 sec. increased F/O2 , = Bang- Bang & flame. Really need the control valves but not in my budget.
Would like to try with valves & Joe's shot of air.

 

I I am attaching a software flow chart:

If you decide to use a micro, you won't really need variable resistors to set the timing parameters, and associated A/D conversion. Instead, you can simply program profiles with all the timing information in the firmware, and use a simple switch to scroll through the profiles. Might want a couple LED's to show which profile you are in though.

 

I also think that using an MCU would be far more flexible, and a much simpler and better choice than hardware alone.

 

I also think that using an MCU would be far more flexible, and a much simpler and better choice than hardware alone.

Agree. I tired my idea I wrote about a couple pages back, using a binary counter and decode logic, and I can't do with with less than 7 chips. So, UC seems the way to go.

 

Agree. I tired my idea I wrote about a couple pages back, using a binary counter and decode logic, and I can't do with with less than 7 chips. So, UC seems the way to go.

Well, if the TS decides to go down that venue, and he chooses to use an 8051, I'll be more than happy to help him with programming.

 

A PICAXE would probably be plenty, as far as microcontrollers go.

A couple of concept notes I'd like to add:

- Burned gasses remaining in the barrel adversely affect the firing. Re-firing (rapid) of the spark plug(s) to ensure complete burning of the propane-oxygen mix has no advantage because the burned byproduct hangs around the electrode inhibiting additional burning.

- As the barrel warms, the combustion (flash point) of the propane & oxygen mixture changes, to a point where combustion can occur without triggering the spark plug. (Yipes!)

- Multiple spark plugs off a single coil is not a viable solution as the plugs tend to foul at different rates. Look into automakers who use individual coils for each spark plug then visit the salvage yard.

-Tweaking of the propane and oxygen mixture and pressures is a wee bit more critical than one would expect. Oxygen "sooting" is not a good thing. Excessive propane to oxygen ratio isn't good either.

- Clean compressed air at a good pressure is critical to cleaning the exhaust (burned gasses) out of the barrel. Burned gasses don't burn. <grin>

I'm in pain so I hope my explanations are adequate.

Have fun!! I'll stay tuned.

joe

 

If you decide to use a micro, you won't really need variable resistors to set the timing parameters, and associated A/D conversion. Instead, you can simply program profiles with all the timing information in the firmware, and use a simple switch to scroll through the profiles. Might want a couple LED's to show which profile you are in though.

Hmmm. I don't know guys. By the time you make it adjustable and add a regulator and stuff I'm not so sure about the micro. You would probably need to power up the drive to at least the spark FET because it needs to turn off fast.
But keep talking. I need some more experience. Maybe I'll buy one and try it.

 

Maybe I'll buy one and try it.

If you buy one, the tab's on me

 

Hmmm. I don't know guys. By the time you make it adjustable and add a regulator and stuff I'm not so sure about the micro. You would probably need to power up the drive to at least the spark FET because it needs to turn off fast..

I understand the need for drivers, but not how that affects the effectiveness of a micro for sequencing.

 

If you buy one, the tab's on me

Boy! What a deal.
Just the other day I was thinking about the PICAXE that was recommended earlier but then I thought I should do a big boy micro with assembly and C+++++ and "stuff" but then I thought, to much to put together that I don't know anything about.
Anyway what I'm getting to is, what is a good one where I can build on what I learn without buying a whole bunch of other stuff to interface it and debug it and program it and and and.
I have a simple one that programs in basic. I built a robot with it. It took me some debug time, but I got it to work and it was a learning experience. But I also discovered it was kind of slow - because of the language I think. Although speed is not an issue here, almost anything would work.
@Brownout
Don't misunderstand me. I like the idea of a micro. Very clean. It's just that I'm not sure how much simpler or cheaper it will be in the long run. Replacing the pots is an example interfacing to the high voltage driver might be another.
I'm not crazy about the pulse generators for the 555 inputs in the hardware design either. But nothings perfect I guess.

 

Boy! What a deal.
Just the other day I was thinking about the PICAXE that was recommended earlier but then I thought I should do a big boy micro with assembly and C+++++ and "stuff" but then I thought, to much to put together that I don't know anything about.
Anyway what I'm getting to is, what is a good one where I can build on what I learn without buying a whole bunch of other stuff to interface it and debug it and program it and and and.
I have a simple one that programs in basic. I built a robot with it. It took me some debug time, but I got it to work and it was a learning experience. But I also discovered it was kind of slow - because of the language I think. Although speed is not an issue here, almost anything would work.
@Brownout
Don't misunderstand me. I like the idea of a micro. Very clean. It's just that I'm not sure how much simpler or cheaper it will be in the long run. Replacing the pots is an example interfacing to the high voltage driver might be another.
I'm not crazy about the pulse generators for the 555 inputs in the hardware design either. But nothings perfect I guess.

I don't like programming MCUs in any other language than assembly. That's because most of the projects that I work on are timing-critical, and you have no idea what the compiler will do when it generates the code. Of course, I've been told many times that it's easy to insert assembly segments in C and Basic, but I find it dumb to make one program in two different languages.
If you want me to, I could send you a few AT89LP4052 for you to play with, courtesy of the house, seriously. But then again, you'd need a device programmer to set them up. Although they can also be programmed serially, and in-system. All you'd need is a computer with a parallel port, the free software, and a few cables.