Electronic circuit for solenoid

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Acdcmonkey1991
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Thu Aug 28, 2008 6:39 pm

I am working on an automatic prototype with a solnoid that strikes open a hammervalve, my question is: Can I get a circuit or something that when I press open a switch it sends delayed electronic signals to turn the solenoid on and off continously so that its like fully auto motion possibly a paintball gun circuit board or no?
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iisthemuffin
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Thu Aug 28, 2008 6:45 pm

Paintball guns do not have ciruit boards to my knowledge.

You probably could do this. I dont think you would need a circuit though.

Im not sure if its such a good idea though. I cant say ive ever heard of a sprinkler being used in full auto. I dont think it would be efficient
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frankrede
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Thu Aug 28, 2008 7:01 pm

iisthemuffin wrote:Paintball guns do not have ciruit boards to my knowledge.

You probably could do this. I dont think you would need a circuit though.

Im not sure if its such a good idea though. I cant say ive ever heard of a sprinkler being used in full auto. I dont think it would be efficient
Some automatic ones do:D
A full auto sprinkler valve cannon can be found on bcvids.com, theres a tutorial on how to build one
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grumpy
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Thu Aug 28, 2008 7:08 pm

iisthemuffin wrote:Paintball guns do not have ciruit boards to my knowledge.

You probably could do this. I dont think you would need a circuit though.

Im not sure if its such a good idea though. I cant say ive ever heard of a sprinkler being used in full auto. I dont think it would be efficient
umm sorry but all electronic paintball markers have electronic fireing boards in them. you can even get boards for most mechanical blow back markers.

@Acdcmonkey1991
a board from a tippman marker may work, as it uses a solenoid and pin to strike the sear causing it to fire.
Last edited by grumpy on Thu Aug 28, 2008 7:22 pm, edited 1 time in total.
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Acdcmonkey1991
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Thu Aug 28, 2008 7:10 pm

no I'm not using the valve The solenoid is striking open a hammervalve, if you are douting that it will work I've already tested it on a 1/2 in sprinkler valve at 50 psi
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rp181
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Thu Aug 28, 2008 9:00 pm

im thinking a 555 ocsillator with a transistor (or relay if its not fast) to get suffiecent current to trigger the solenoid. It would also simplify things if the solenoid had spring return.
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iisthemuffin
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Thu Aug 28, 2008 9:22 pm

Oh sorry. I was under the impression that automatic paintball markers used blow back for auto.

And i wasnt doubting i twould work. I was aying you probably could do it without a circuit. I was only questioning its efficiency as i have never seen one before.
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VH_man
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Thu Aug 28, 2008 9:28 pm

nice to see someone using the idea of a pulsed "push" style solenoid hammer valve.

what i reccomend is........... just like rp181 said, a 555 occilator circuit. if neccecary, i can give you a schematic for something that will PROBOABLY give you what you need........ ecept the current.......

the way the ones in paintball guns work is to quickly Charge and Discharge a capacitor around the size of a Photo Flash capacitor....... but without some clever electronics making a 555 work around those currents and voltages would be INSANE.

what i reccomend is MOFSET power transistors, which can be purchased in the realms of at LEAST the current neccecary to give a solenoid the BLAM it needs. of course, relays are cheaper, but they take up more space and wear out over a LOOONG time, and not to mention arent exactly lightning fast.

BTW, @ rp181: 100% of solenoids have spring return...... the way a solenoid works is to pull a ferromagnetic rod into the center of the electromagnetic field created by the coil. this ALWAYS moves the object inward. to make a PUSH solenoid, all they do is attach something to one end of the ferromagnetic peice that makes it "push" out when the peice goes back to center, instead of having the ferromagnetic peice "pull" inwards, like the solenoids found on sprinkler valves. all of these have a spring return, because..... well....... reversing the polarity on a solenoid doesnt do much....

wow that was a long post...... its been a while........
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rp181
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Thu Aug 28, 2008 9:42 pm

Why would it be difficult with those voltages/ currents? You dont feed it through the 555, you have a 555 trigger a SCR/IGBT. SCR's will ensure all the charge goes into the solenoid, but would be slower than a IGBT. You will need a smaller transistor to trgger the SCR/IGBT to get suffiecient current.

Yet another opption is a LM339 Quad comparator in junction with a 555 to use optics to trigger firing. When it detecs the projectile, it fires. It would also prevent jams.
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VH_man
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Thu Aug 28, 2008 9:47 pm

another idea i had........ except i was going to just use a pair of "eyes" from a smart parts Ion to simplify the electronics neccecary for operation.

and i guess your right........... i spoke too soon...... im educated in the electrical field of things, but, i taught myself, so theres proboably things i overlooked, such as current. i have a vauge understanding, but when it comes to some things im just guessing..... i apologize. ill trust you..... not me.

i actually have a "clicker" circuit out of a 555 i made a long time ago..... hmmmm...........

whatever you do, good luck, and i can supply you with a "clicker" circuit
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Fri Aug 29, 2008 5:22 am

Only little problem with an SCR is that it will never turn off. Best to just use the 555 to drive a mosfet, and set it's duty cycle/frequency to the fire rate you want.
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VH_man
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Fri Aug 29, 2008 6:52 am

wait........ isnt an SCR used for switching capacitors in railguns and coilguns?
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Fri Aug 29, 2008 10:39 am

VH_man wrote:wait........ isnt an SCR used for switching capacitors in railguns and coilguns?
Different beastie.

An SCR turns on when voltage is applied to the gate. It stays on, regardless of the state of the gate, until current is removed from the other two contacts.

SCRs are usually used in AC circuits. To turn it off you remove the gate voltage then wait for the AC signal being controlled to drop to zero volts to turn the device off. If you use an SCR in a DC circuit the SCR will never turn off once it's been turned on.

When an SCR is used in a coil gun the SCR is turned off when the power storage capacitor's voltage drops to zero. (Coil guns may look like DC circuits but the majority operate as AC circuits.)

The 555 plus a high power transistor would certainly work. The 555 has the advantage that it is easy to control the cycle rate and the duty cycle.

A relay wired as a buzz coil should also work. Most small relays will buzz at several hundred hertz when wired as a buzz coil. That should be more than fast enough for this use. The challenge with the buzz coil would be controlling the frequency.

Below is a standard 5-pin automotive relay wired up to act as a buzz coil. The output is used to drive a flyback transformer. You should be able to replace the flyback with the coil of your solenoid.
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You should be able to change the frequency by changing the 120uF capacitor. In the circuit above the cap is a photocap and the circuit oscillates at 100-200 Hz.

Another possiblilty would be to mechanically actuate the hammer valve. I wonder if the motor with offset weight used in cell phones to make them vibrate would work? You would use the offset weight as a hammer.
Tiny vibrating motor for $1.25
Or, a generic small DC motor with a homemade offset weight.
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rp181
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Fri Aug 29, 2008 6:10 pm

when you say coilguns opperate on a AC circuit, do you mean ringing?

555 and mosfet is best bet. i would make one to test it out, but all my Fets are high powered (harder to trigger)
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Sat Aug 30, 2008 10:16 am

rp181 wrote:when you say coilguns opperate on a AC circuit, do you mean ringing?
They may ring but that isn't what I mean. They are AC circuits (usually) since power comes from a big-ass capacitor. The voltage changes (drops) with time when the gun is fired. The current lags the voltage by a quarter wave. Since the voltage and current are both changing as a function of time it is an AC circuit. Resitances should be expressed as impedances, current lags voltage, etc.
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