Props Reach ar electronics help!!

[nrettenmaier]

All you electronics geniuses, I need your help!!

I'm working on building the AR from Reach and I want the bolt to actually move when I pull the trigger, as if a round was actually being fired. I've been looking online and from what I've seen it seems like people usually do this one of two ways, either with a solenoid or with a small electric motor. However, from what I've been able to find out, they both have their downsides (the solenoid takes up a lot of energy and the motor makes noise)

I was wondering if any of you guys have ever done this and had any ideas for me. Or if anyone else knows of any other ways to do this or can just give more information about one of the methods mentioned above (what solenoid/motor to use, etc.). Also, does anyone knw of any sites I can look at that would help me out? Let me know!

I should mention that I don't necessarily want to be able to feel recoil on it (so it doesn't need to be that powerful). I just want the bolt to move.

Thanks in advance

 

[tmccarty23]

I don't know much about electronics, but those ways sound good to me. But I think that no matter what you do, there will still be substantial noise. You could always insulate the motor, but then you would have to worry about overheating if you use it too much. You could always try using two tension springs, like the system used in the Out The Front (switchblade) knives, so that when you pull the trigger, the slide will kick back and the forward spring will pull it back into place. You would have to put a locking mechanism in the receiver area and link it to the trigger, but I think this would be simple method, if you can manage the balancing act between the two springs.

I have never tried this personally, but it's just a thought.

 

[active84u]

Dont know if this might help but consider pneumatics too. I know several paintball markers have exterior 'bolts' that travel as the marker cycles at each trigger pull. Have a look at some old Tippmann markers, and co2 supply systems. Old Splatmaster pistols have a small co2 supply that could be mashed to use?

 

[Ravenwolf]

I'd go with a solenoid and a return spring.
i.e.
a trigger pull pulses a current through the solenoid, charging it, and drawing the bolt back. when the current dies, the springs return the bolt to the foward position.
or,
a single solenoid could be used to move the bolt back and forth, but you would have to be able to reverse the direction of the current through the solenoid to do so.

either way, i wouldn't worry too much about the solenoid's power usage, as you likely wont need a big one.
the plus on the first would be that you could fairly easily set it up so that you could select auto/semi/burst fire modes. (ok, relatively simple anyways )

http://forum.allaboutcircuits.com/

I used to frequent that forum alot. They've always been helpful.

lol, now the brain is spinning on how to do the slect fire i mentioned XD

feel free to pm/email me if you have any other questions

 

[Combust]

My two cents here is to use a continuous rotation servo with a mechanical piston like linkage. Upside is that its simple to use as its just a motor (All the electronic feedback gear has been removed) and its small size. The down side is you would need a way to make it stop at the closed/open position. Two small switches, one to start the rotation (Trigger) and then one to stop the rotation. You would need a relay, 2 switches and a battery for this to work.

I can picture it in my head but putting it down on paper... Here are pictures

Servo how-to.
http://www.instructables.com/id/How-to-modify-a-servo-motor-for-continuous-rotatio/

Linkages:

 

[nrettenmaier]

either way, i wouldn't worry too much about the solenoid's power usage, as you likely wont need a big one.
the plus on the first would be that you could fairly easily set it up so that you could select auto/semi/burst fire modes. (ok, relatively simple anyways )

http://forum.allaboutcircuits.com/

I used to frequent that forum alot. They've always been helpful.

lol, now the brain is spinning on how to do the slect fire i mentioned XD

feel free to pm/email me if you have any other questions

Thanks for the site, I've just been able to look around it briefly but it seems like it'll be really helpful

I've been thinking some more and I think i am going to go with the solenoid, it just seems like the easiest. I do want it to be able to go full auto (hold the trigger and have the bolt go back and forth) so it seems like the best bet. Do you happen to remember what I would need to set up the solenoid so I can do full auto? (I'm fairly new to electronics) I know you said you don't remember much but if you remember anything about how to do it let me know, it would be a HUGE help

On a side note it seems like there are two different types of solenoids, those meant for short use and long rest time and those meant to work continuously for a long time. I'm guessing I need the second time but could anyone who knows a little bit more about this confirm that for me.

thanks guys, I really appreciate all your help, and don't worry, I'm still looking in to all the other stuff you guys suggested too!

 

[thatdecade]

I know you've made your decision, but the most reliable setup really is a motor connected to a piston.


Let me know if you get the solenoid figured out. I was disappointed with my work on solenoids, makes a clicking noise when fired. I was using a solenoid meant for continuous firing.

I threw some notes up a while back on a battery powered firing circuit for solenoids. Here are two of my circuits, the first is simple to understand, I used the second to provide some safety to the person pulling the trigger.




Looks like this assembled

 

[Ravenwolf]

I've been thinking some more and I think i am going to go with the solenoid, it just seems like the easiest. I do want it to be able to go full auto (hold the trigger and have the bolt go back and forth) so it seems like the best bet. Do you happen to remember what I would need to set up the solenoid so I can do full auto? (I'm fairly new to electronics) I know you said you don't remember much but if you remember anything about how to do it let me know, it would be a HUGE help

For the full auto, I'll have to do some research. not built one myself, though it'll deffinitly be fun giving it a shot (the brain needs much needed exercise in this area.... yay stagnation)

@thatdecade

mind if i run some things by you later? it's been a few years since i've done circuit design

 

[nrettenmaier]

I know you've made your decision, but the most reliable setup really is a motor connected to a piston.

I know I said I had decided on the solenoid, but what I really meant to say was that I was leaning toward the solenoid. The motor and piston does seem relatively simple (I'm still not really sure how to do full auto with a solenoid). Like I said I'm realtively new to electronics so I'm still thinking/researching/learning.

Thanks for the circuit diagrams too, if I do go with the solenoid they will definately come in handy

@ Ravenwolf
Its always good to exercise the brain!! Any help you can give is much appreciated

 

[thatdecade]

Full auto is done with an IC. The second circuit diagram can be connected directly to a 5V control circuit generating square wave pulses, like a microcontroller or a simple 555 clock circuit.

 

[Ravenwolf]

@thatdecade: that's what i'm working on
working to incorporate an ammo counter and maybe a couple other things as well. deffinitly going overboard with this, lol
If i had something to dump VHDL into, it'd be done already XD (stupid budget constraints...lol)

What solenoid did you use?

 

[nrettenmaier]

hey guys, what kind of heat would the solenoid/motor put out. I know this is going to depend on the size of the solenoid/motor but in general for this kind of use is it going to be a lot? (I'm more worried about the heat of the solenoid rather than the motor)

I'm asking because the solenoid/motor is pretty much going to be competely enclosed in the AR so its going to be hard to dissipate any heat quickly.

 

[MW Immortalking]

could we please get this moved to the electronics thread?