Coil-Gun controller made from TTL chips (show-off your controller too!)
muller, Tue Apr 04 2006, 07:18PMThis is a 3-stage Coil-Gun timer made from basic SSI TTL chips made for McFluffin. I built this from 15 year old parts I found in my dads garage including wire and breadboard. I have to pick up a few replacement dip switches as 2 of them are faulty. I might post up my schematics for kicks if people wanna see them.
Now all we have to do is build the 3-stage Coil-Gun.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
Madgyver, Tue Apr 04 2006, 08:01PM
So....
first, what does the board do?
second, what does this thread do in computer science?
Madgyver, Tue Apr 04 2006, 08:01PM
So....
first, what does the board do?
second, what does this thread do in computer science?
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
Steve Conner, Tue Apr 04 2006, 10:30PM
Third, does it work?
Fourth, what is this thread doing in General Science, I reckon it should be in EM Projectile Launchers.
Steve Conner, Tue Apr 04 2006, 10:30PM
Third, does it work?
Fourth, what is this thread doing in General Science, I reckon it should be in EM Projectile Launchers.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
rupidust, Wed Apr 05 2006, 09:13AM
What is the question, problem, or need?
Appears to be 3 pulse timers with or without optics. Are the dip switches for loading 8-bit parallel binary numbers into 8-bit counters? Are the stage drivers included such as darlingtons, mosfet drivers...? You have to start from somewhere, so these descrete combinational logic circuits are a good starting point. I started out with a love of interfacing all TI's 7400 logic with BCD counters, 7-segment drivers, static ram, shift registers, ..etc.. to build all kinds of circuits. Once building these kinds of circuits becomes easy and successfull, a true appreciation grows for alternative (in those days, but mandatory now adays) low chip count reconfigurable microprocessing control.
For instance, the below image is of a multistage coil-gun controller of PIC core. The code supports 4 stage for this 18 pin IC but the image is only displaying the circuit for a 2-stage coil-gun. There is only one logic chip, the PIC '819. All other ICs are mosfet drivers to switch the SCR/IGBT devices and drive the onboard boost converter.
Yes, send them schematics.
rupidust, Wed Apr 05 2006, 09:13AM
What is the question, problem, or need?
Appears to be 3 pulse timers with or without optics. Are the dip switches for loading 8-bit parallel binary numbers into 8-bit counters? Are the stage drivers included such as darlingtons, mosfet drivers...? You have to start from somewhere, so these descrete combinational logic circuits are a good starting point. I started out with a love of interfacing all TI's 7400 logic with BCD counters, 7-segment drivers, static ram, shift registers, ..etc.. to build all kinds of circuits. Once building these kinds of circuits becomes easy and successfull, a true appreciation grows for alternative (in those days, but mandatory now adays) low chip count reconfigurable microprocessing control.
For instance, the below image is of a multistage coil-gun controller of PIC core. The code supports 4 stage for this 18 pin IC but the image is only displaying the circuit for a 2-stage coil-gun. There is only one logic chip, the PIC '819. All other ICs are mosfet drivers to switch the SCR/IGBT devices and drive the onboard boost converter.
Yes, send them schematics.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
ragnar, Wed Apr 05 2006, 01:52PM
Some people post just to pimp stuff, too
How long did it take you to find the DIP switches were faulty?
ragnar, Wed Apr 05 2006, 01:52PM
wrote ...
What is the question, problem, or need?
What is the question, problem, or need?
Some people post just to pimp stuff, too
How long did it take you to find the DIP switches were faulty?
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
Barry, Wed Apr 05 2006, 03:44PM
Nice looking layout. I see the little '555 oscillator chip almost in the center. It all looks like an open-loop coil timer, where each stage is turned on/off according to a selectable time count. If so, it is very much like my Mark 1 coilgun. A great idea if I do say so myself.
I found the outcome was not too successful because a simple timer-based coilgun does not adjust itself for minor changes from shot to shot. With the high accelerations involved, this magnifies any timing error in each subsequent stage. It takes only a coil or two until the timing is too far off to be helpful.
Those DIP switches make an easy circuit to adjust (assuming the switches work!) and play around with. You might even consider overlapping coil times to see if two-coils-turned-on-together can improve the accelerations. However I think most people will find that closed-loop controllers with position detectors will permit more stages and higher acceleration.
Cheers, Barry
May the electromagnetic force be with you.
[Edit: Go here
to learn how to post pictures.]
Barry, Wed Apr 05 2006, 03:44PM
Nice looking layout. I see the little '555 oscillator chip almost in the center. It all looks like an open-loop coil timer, where each stage is turned on/off according to a selectable time count. If so, it is very much like my Mark 1 coilgun. A great idea if I do say so myself.
I found the outcome was not too successful because a simple timer-based coilgun does not adjust itself for minor changes from shot to shot. With the high accelerations involved, this magnifies any timing error in each subsequent stage. It takes only a coil or two until the timing is too far off to be helpful.
Those DIP switches make an easy circuit to adjust (assuming the switches work!) and play around with. You might even consider overlapping coil times to see if two-coils-turned-on-together can improve the accelerations. However I think most people will find that closed-loop controllers with position detectors will permit more stages and higher acceleration.
Cheers, Barry
May the electromagnetic force be with you.
[Edit: Go here
to learn how to post pictures.]Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
EN, Wed Apr 05 2006, 07:58PM
As this thread is a good place to to show off with coilgun controllers, I will also do so.
This 12 stage optical controller is a good examle of how simple an SCR coilgun controller can be because it needs no timing circuits whatsoever.
EN, Wed Apr 05 2006, 07:58PM
As this thread is a good place to to show off with coilgun controllers, I will also do so.
This 12 stage optical controller is a good examle of how simple an SCR coilgun controller can be because it needs no timing circuits whatsoever.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
rupidust, Wed Apr 05 2006, 08:59PM
No circuits never the less timing is inevitable. The optics is the timing. Proper spacing distance between successive coil stage and sensor have to be adjusted for optics. You cannot place the optical sensors at the same fixed position for all stages and expect the results to be better compared to the optics being placed slightly further away for each stage. If optics are at the same fixed position for each stage, then the coil/optic assembly would be in need of distance adjustment as above. This physical placment/adjustment is in essence a form of timing. Alter either the slug mass, start position, cap voltage, or coil winding, and the conscequence is the repositioning of the optic sensors.
rupidust, Wed Apr 05 2006, 08:59PM
EN wrote ...
This 12 stage optical controller is a good examle of how simple an SCR coilgun controller can be because it needs no timing circuits whatsoever.
This 12 stage optical controller is a good examle of how simple an SCR coilgun controller can be because it needs no timing circuits whatsoever.
No circuits never the less timing is inevitable. The optics is the timing. Proper spacing distance between successive coil stage and sensor have to be adjusted for optics. You cannot place the optical sensors at the same fixed position for all stages and expect the results to be better compared to the optics being placed slightly further away for each stage. If optics are at the same fixed position for each stage, then the coil/optic assembly would be in need of distance adjustment as above. This physical placment/adjustment is in essence a form of timing. Alter either the slug mass, start position, cap voltage, or coil winding, and the conscequence is the repositioning of the optic sensors.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
muller, Thu Apr 06 2006, 12:22AM
Wow, thanks everyone for the great responce!
Before I continue I would like to clarify that I fixed a mistake In my first post. I accidently left out the word "timer" after coil-gun. so yeah this is not the coil-gun. But I assume everyone figured that out.
I probably should've had some more explanation with this.
But yeah, Barry hit what I had pretty much spot on.
Basically I have a 555 driving an 8-bit counter. I then compare the counter to the dip switches. Some j/k's lock the signal high so that the coils fully discharge. The stray wire at the top is my counter & j/k reset(I really need to go to jameco and get some switches).
I didn't take very long to find out the dip switches were faulty. I tested each section as I went along with my o-scope(you never know with 15-20 year old chips you find in buckets). Right now the 555 is slow enough that I can visibly see the voltage spike on my o-scope.
If anyone is wondering what the mess of wires on the left-most rail is I'll tell you. I ran out of comparitor chips so I jurry rigged one. I XOR each bit, invert them, and and them all together for an equals circuit.
The output of the circuit are the 3 brown wires coming from j/k's in the right-ish bottom-ish corner.
People have given me some great advice on what I should do If I build another controller (the need for sensors mabye). But I realize that right now I lock my output to high until a reset. I did this to make sure that there was enough time for the coils to charge. Is this wise? From a recent experiment I realized I might need some sort of cut-off time so that the projectile doesn't get sucked backwards.
Those controllers all look cool and have given me some real insight!
muller, Thu Apr 06 2006, 12:22AM
Wow, thanks everyone for the great responce!
Before I continue I would like to clarify that I fixed a mistake In my first post. I accidently left out the word "timer" after coil-gun. so yeah this is not the coil-gun. But I assume everyone figured that out.
I probably should've had some more explanation with this.
But yeah, Barry hit what I had pretty much spot on.
Basically I have a 555 driving an 8-bit counter. I then compare the counter to the dip switches. Some j/k's lock the signal high so that the coils fully discharge. The stray wire at the top is my counter & j/k reset(I really need to go to jameco and get some switches).
I didn't take very long to find out the dip switches were faulty. I tested each section as I went along with my o-scope(you never know with 15-20 year old chips you find in buckets). Right now the 555 is slow enough that I can visibly see the voltage spike on my o-scope.
If anyone is wondering what the mess of wires on the left-most rail is I'll tell you. I ran out of comparitor chips so I jurry rigged one. I XOR each bit, invert them, and and them all together for an equals circuit.
The output of the circuit are the 3 brown wires coming from j/k's in the right-ish bottom-ish corner.
People have given me some great advice on what I should do If I build another controller (the need for sensors mabye). But I realize that right now I lock my output to high until a reset. I did this to make sure that there was enough time for the coils to charge. Is this wise? From a recent experiment I realized I might need some sort of cut-off time so that the projectile doesn't get sucked backwards.
Those controllers all look cool and have given me some real insight!
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
McFluffin, Thu Apr 06 2006, 01:28AM
Nice job Muller. Now we just need to wine the other coil gun stages and get your DIP switches and the driver for the SCRs, and some optical sensors. I need to check what most people use for those. I hear people use lasers, but I figure simple IR sensors would work too. Glad to hear you are getting some use out of my scope.
McFluffin, Thu Apr 06 2006, 01:28AM
Nice job Muller. Now we just need to wine the other coil gun stages and get your DIP switches and the driver for the SCRs, and some optical sensors. I need to check what most people use for those. I hear people use lasers, but I figure simple IR sensors would work too. Glad to hear you are getting some use out of my scope.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
williamn, Thu Apr 06 2006, 05:57AM
Since we are showing off coilgun controls, here is my 3 stage optically triggered IGBT coilgun pistol. I use IR LEDs + photodiodes and comparators for the IR gates, monostables drive the IGBT gates for a specified duration. The last two stages are powered by one capacitor (pulse times are quick enough to only deplete the cap voltage by 25%) The charger also uses a comparator to sense the bank voltage, turn off the charger, and turn on the logic. This is an oldie but goodie, my new 5 stage version also incorporates delay times.
Coilgun control photo
williamn, Thu Apr 06 2006, 05:57AM
Since we are showing off coilgun controls, here is my 3 stage optically triggered IGBT coilgun pistol. I use IR LEDs + photodiodes and comparators for the IR gates, monostables drive the IGBT gates for a specified duration. The last two stages are powered by one capacitor (pulse times are quick enough to only deplete the cap voltage by 25%) The charger also uses a comparator to sense the bank voltage, turn off the charger, and turn on the logic. This is an oldie but goodie, my new 5 stage version also incorporates delay times.
Coilgun control photo
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
muller, Thu Apr 06 2006, 06:15AM
These controllers are really cool! keep em comin'.
muller, Thu Apr 06 2006, 06:15AM
These controllers are really cool! keep em comin'.
Re: Coil-Gun controller made from TTL chips (show-off your controller too!)
rupidust, Thu Apr 06 2006, 09:54AM
End products for functioning pistols:
2 Stage with built in 15 watt charger. Configured and controlled by RS232. Auto charge after each shot
3 stage with built in 50 watt charger. Configured and controlled by IR-remote. Auto charge after each shot. Selectable Full or Low power shots.
rupidust, Thu Apr 06 2006, 09:54AM
End products for functioning pistols:
2 Stage with built in 15 watt charger. Configured and controlled by RS232. Auto charge after each shot
3 stage with built in 50 watt charger. Configured and controlled by IR-remote. Auto charge after each shot. Selectable Full or Low power shots.
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