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New/Stumped/Need Help - Solenoid Simulated Recoil Answered

I have the body of an old Airsoft M4A1 and instead of throwing it away i had the idea of making it have simulated recoil through a solenoid. Now of course i realize that i could never make something with the kick of a real gun but at least something i could feel.(Like the arcade games) I have had some really successful tests with LI-PO batteries but they were all to big and had bad connection spots, and then i tried 6 AA batteries in series with a 1000uF 16v capacitor(I dont know if i am using the right capacitor or if i wired it incorrectly), but my attempts have failed, i am new to circuits and electricity, any thoughts on a power source,or ideas on different angles i could go.

P.S.-The solenoid is homemade and is made up of 14g wire (All i had laying around)-And functioned well with a 3.7v 6000mAh Li-Po battery(Recycled from an old portable charger)


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Jack A Lopez
Jack A Lopez

1 year ago

If I had to guess, I would guess your solenoid would work better, be better matched to a low voltage, DC, supply, if it had more turns of, more thin gauge, wire.

The only shortcut I can think of, regarding solenoid design, is to just buy one, or pull one out of some other piece of junk, like those golf putting toys, that use a solenoid to kick the ball back to you. Or an old, ding-dong, type doorbell, with a solenoid, or two, to hit a pair (one ding and one dong) of metal chimes.

Or if you happen to know someone who has an old pinball machine, that is, like, the solenoid jackpot. Because one old pinball machine, probably has tens of kicker solenoids in it.

If you actually want the math for solenoid design, well, I think it kind of looks like an RLC circuit,


but made more complicated by the fact L (inductance) changes as the steel plunger moves. Also energy is stored in the kinetic energy, 0.5m*v^2, of the moving steel plunger, in addition to the usual places for an RLC network: 0.5*C*V^2, in the capacitor, and 0.5*L*I^2, in the inductor.

Also I think you kind of need something to switch the current that drives the solenoid, like a big transistor, or SCR, or relay, or... I also recall seeing a capacitor bank switched by a mousetrap.

I saw that moustrap (or maybe it was a rat trap) in a Youtube video one time, but who knows if I would be able to find it again. I mean the moustrap switch had some advantages: low tech, kinda fast, and capable of switching big current, depending, roughly, on the area of the metal contacts that get slammed together.

Also I noticed the Wikipedia article for "Solenoid" had a nice picture of one, a cut away view, with a steel plunger and everything, here,

That picture came from a PDF of a text book on electrical engineering, that is free from copyright now (because it was published approximately 100 years ago.) And you can download it from Google, at the link below (via the little button with a "gear" icon on it)


Who knows? Maybe that old text can give you some good ideas about the solenoid you want to build?