Boardless electro-pnuematic automag. Possible?

So, I have an idea for building an electro-pnuematic automag sans any kind of board. The problem is that I know zilch about electronics and all that. I managed to build my own pneumag easily enough, but that didn’t involve soldering and capacitors and stuff like that, so I could really use some feedback and direction on this.

I have been interested upgrading my pneumag with electronics for a while, but for some reason I didn’t think I could fit a battery and board and all that into the frame. I’ve also wanted to add eyes, but that can be quite a process as well.

So I thought of this design. (Pardon the crappy paint diagram.)

http://a2.sphotos.ak.fbcdn.net/hphot...98148220_n.jpg

Basically, it’s a pneumag with an MPA piston pushing on the sear. LP air comes in from somewhere (probably through the rail). Instead of the trigger hitting an MSV valve, however, there is microswitch number 1 (MS1) taking the hit and eventually transferring a signal to the solenoid, which triggers the piston instead.

Now, I know for an electro pneumatic automag, you can’t just add a solenoid and a battery. You need a capacitor (for some reason I don’t fully understand), and you also need a board. The board controls things like dwell and ROF, which are both important. You also can’t have eyes without a board to know what to do with that signal. Dwell, though, seems to be the most important. Without it, there might be accidental contact, causing all sorts of problems.

Therefore, I thought of adding ANOTHER microswitch to the equation (labeled MS#2). This switch would be wired in parallel to the first (meaning that the marker won’t fire unless BOTH switches are activated). This switch would satisfy the requirements for dwell and eyes. When there is a ball in the breach pushing down on the switch, then the marker will fire when you pull the trigger. When the bolt is forward, firing the ball, you can technically fire the marker again (but that won’t matter). When the bolt comes back, though, and for the milliseconds it takes for anther ball to fall into the chamber, the marker won’t fire because that second microswitch isn’t triggered.

So…. Would this work? Or is there something I’m overlooking? Please help me out.

Assuming it all worked, one potential problem I see is that you have the loading ball activate your second switch. What if the ball breaks? All the paintball goo will gum up the switch, and you would have to disassemble the entire marker. When the bolt moves over the switch and you still have your finger on the trigger, it would also tell the ram to fire, wasting battery and creating unnecessary wear. It'd be like a little jack hammer going off in there every time it fired.

It's an interesting idea. However, MS#2 would get shredded by the bolt or bolt spring when the bold returns.

I don't think the bolt spring would influence, as the switch would be farther up, where the ball drops. The spring stops before that point.

Maybe it could double as a ball detent :D

Electrical & computer engineer here. I'm busy and don't have time for a full breakdown, so the short answer is yes, but not with switches.

It has been done by an enterprising gentleman on here whose post I cannot manage to find. He built a circuit around a 555 timer, a very simple integrated circuit that produces a timed signal. This signal correlates to both the dwell and the ROF. Using a few resistors, capacitors, and a bit of math, the timer can control the solenoid. Eyes produce an analog (continuous 0-5v) signal, which once converted to digital (either 0 or 5v) can be used to shut off the timer when a ball is not chambered. All of this, using a trigger microswitch, MPA-3, and SY070, was built into a classic frame. Fully-auto only, IIRC, but a great sleeper.

tl;dr Yes, is do-able and has been done, but it does require some electronics knowhow. If you would like, I can lay out some more details later.

what frame do you have?

a cap is optional depending on the noid/board used.

A UTB is very small

if you don't want your LPR in the frame I see no reason you cant fit a battery and UTB in ANY frame.

Hill did a EP sleeper in a classic CF frame.

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Originally Posted by Nanotech

Electrical & computer engineer here. I'm busy and don't have time for a full breakdown, so the short answer is yes, but not with switches.

It has been done by an enterprising gentleman on here whose post I cannot manage to find. He built a circuit around a 555 timer, a very simple integrated circuit that produces a timed signal. This signal correlates to both the dwell and the ROF. Using a few resistors, capacitors, and a bit of math, the timer can control the solenoid. Eyes produce an analog (continuous 0-5v) signal, which once converted to digital (either 0 or 5v) can be used to shut off the timer when a ball is not chambered. All of this, using a trigger microswitch, MPA-3, and SY070, was built into a classic frame. Fully-auto only, IIRC, but a great sleeper.

tl;dr Yes, is do-able and has been done, but it does require some electronics knowhow. If you would like, I can lay out some more details later.

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I believe this was done by Spider-TW. He has an even more extensive writeup on MCB (under the username Spider!)

sorry that I don't have any links to threads but it should be relatively easy to find.

Wow. Thanks for all the info, guys.

I found Spider-TW's thread and looked at his set-up. I think that's pretty much EXACTLY what I want to do (even though his set-up doesn't have eyes). Only problem is I think I'd be in way over my head. :(

I'll have to think this over and weigh my options. I was heading in this direction because I thought it would be cheaper/easier than getting a UTB and putting a board into my pneumag, but after looking at Spider's thread, I'm not so sure. Even if it ends up being cheaper, it would take a lot of time to figure everything out, and time=money to me right now.

Nanotech, you have any interest in a commission job? :D

I wanted to do this using a switch that was tripped and reset on the pull. They are available but hard to find. They are designed to activate and deactivate on the pull stroke and the release stroke. So it would be two shots per pull. Also no capacitor is needed with the SMC noid. They will hit high 20s without it. You only need a cap if the noid is a clapper or large 3 way. I could use a mac33 as there would be way enough space with no board.

I could also design a cam on the back of a trigger to do the same thing with a standard microswitch. Then the speed of the pull will determin dwell but if it is longer than 10 ms it will be fine and a longer dwell up to infinity will not effect the marker efficiency only the noid. Add a tension release trigger to insure a certian amount of pull force to keep the dwell short enough to keep the noid cool and done.

The only other issue is that the noid is only 5 volt so a small voltage regulator would work and they are so small that it would fit on top of the plug for the battery.

The gears in my head are turning and I for see a very fast electro/mechanical in the future.

Here is the general idea I had.
http://i971.photobucket.com/albums/a...s/DSC01185.jpg

Please dont say that this is impossible. :D Im to busy to build this at the moment. :p

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Originally Posted by hill160881

Please dont say that this is impossible. :D

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Definitely impossible. :p

There's lots of ways to time mags. While we try not to let the sear push up with the bolt out, a good bolt spring usually covers that problem, so all you have to do is trip it in the first place.

While it's fine to put 9vdc on the little SMCs for 10ms out of 60, they do overheat as you leave them on longer.

As long as you are mounting switches, you could also use some break beam eye pairs like you get out of disk drives and such to time the sear.

My timer circuit was semi-auto only, as it is essentially two parallel monostable timers and has to be re-triggered each time.

The hard part is making sure that you can't re-trigger the sear during the 50ms or so that the reg is charging the dump chamber. From the outside, that looks the same as it is ready to fire, unless you put a little pressure switch in there. :)

Then again, the timing on Hill's anti-mag might make it all much easier.

The mac33 would be my choice as a tester noid as it is stronger and I have several. With 9 volts I wont need a cap for sure, haha.

If I have time this weekend I will see about hammering out a prototype. I have all the parts.

I'm so jealous you guys actually know what you're doing. All I want is an electric trigger that shoots semi when turned on and stops shooting when turned off. :cry:

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Originally Posted by hill160881

The mac33 would be my choice as a tester noid as it is stronger and I have several. With 9 volts I wont need a cap for sure, haha.

If I have time this weekend I will see about hammering out a prototype. I have all the parts.

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You sure you have everything??? Or do I need to open the shop again? :D

DM

Last time I sold my soul to the devil it turned out pretty good(the classic sleeper) so why not again? :D

So I may need to do some shopping ;)

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Originally Posted by rawbutter

I'm so jealous you guys actually know what you're doing. All I want is an electric trigger that shoots semi when turned on and stops shooting when turned off. :cry:

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We almost never know what we are doing. lol

Its more "what would happen if we do this" type of thing.

You need to consider battery efficiency with any designed circuit. The problem with most adhoc timed circuits is a wasted amount of power. That is where tiny programmable circuits come into their own.

You can get everything you want in a simple 8 pin tiny AVR for about $1.75. The outputs of these can drive 40mA of current to supply any power transistors you need to operate a solenoid. There are 6 I/O pins so you can program eyes into it. For a simple semi marker with eyes, it doesn't get any simpler than that. I know it needs a programmer and you can buy one ready to go for $22.00. That'll give you the option of programming most AVR devices.

Spyder board on amazon for 13 bucks ... here is the link

http://www.amazon.com/dp/B002RMHI9U/...SIN=B002RMHI9U

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Originally Posted by athomas

You need to consider battery efficiency with any designed circuit. The problem with most adhoc timed circuits is a wasted amount of power. That is where tiny programmable circuits come into their own.

You can get everything you want in a simple 8 pin tiny AVR for about $1.75. The outputs of these can drive 40mA of current to supply any power transistors you need to operate a solenoid. There are 6 I/O pins so you can program eyes into it. For a simple semi marker with eyes, it doesn't get any simpler than that. I know it needs a programmer and you can buy one ready to go for $22.00. That'll give you the option of programming most AVR devices.

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Wow. You are totally speaking Latin to me. I never knew how little I understood electronics. :wow:

I'll have to start reading up on some stuff.