how to make a mini solenoid turn on and off superfast continuously

[meechee]

i want to use a 12v mini solenoid in my paintball gun to automaticly keep the trigger mechanism continuously turn off and on about 15 times per second. my goal is to turn it into an automatic firing paintball gun. kind of like how a led flashes but instead of the led i want the solenoid to turn on and off repeatedly as im holding down the switch. any suggestions on how the circuit works. also there is an upgrade called the egrip, basically i want to make something just like it but with only 1 mode automatic firing about 15 paintballs per second. is there a circuit i can use or one kinda similar? thanks

 

[MrAl]

Hi,

A solenoid is basically a coil of wire with a center that can move in and out. The coil forms an inductor.

Because it is an inductor, when you apply a voltage it will not conduct right away but will take a finite time to conduct to some decent level of current. The time it takes depends on how much inductance there is in the coil. The time it takes to conduct greatly affects the time it takes to pull in. No current, no pull. High current, high pull in force. Too high of a current, wire burns up.

If a 12v solenoid takes 10ms to move 1mm then that is what you are stuck with unless the solenoid can take a higher voltage. If you apply twice that voltage (which would be 24v here) that means it would take 5ms to move 1mm. If you double that, it would take 2.5ms to move 1mm. This works up to a point anyway.
But the other problem that comes in is that the current might go too high after a certain period of time, so you'd have to limit the current. This takes a special circuit that can put out say 48v and limit the current to whatever the solenoid can take figuring in the duty cycle and all. Alternately you might be able to limit the 'on' time.

But of course this only works if the 12v solenoid can take the full 48 volts without breaking down. You'd have to check the manufactures spec's to see about this, or do your own experiments possibly sacrificing a solenoid to do it.

If you have the freedom to select a solenoid then you would want to select one that has the lowest inductance and of course meets the force spec you need to do whatever it has to do.

 

[canadaelk]

And the $64k Q is:?

I have not done any test, but: doubling the voltage should be similar to the behaivour of a resistor: E^R=W. By your reasoning than, the solenoid should pull within 2.5ms (neglecting mechanical stuff)

What is the app? E

 

[meechee]

thanks for the replies. your advice did 2 things for me. 1 it saved me alot of experimental failure time. and 2 im back to square 1. i guess i need to do some math. i will be back with another question soon im sure. again thank you both

 

[canadaelk]

If you use a 12V solenoid you should not have a problem pulsing it with 50V (keep a check on the temperature of the coil). The safe hold voltage, depending on the load, could be as low as 7V. E

 

[MrAl]

Hi,

That's what i would think too, but i dont want to specify something where i have no manufacturer specs in front of me to go by. I would think that the wire insulation could easily handle 48v for example.

 

[BioniC187]

Its a paintball gun, he isn't going to carry around 3 car batteries to supply a 50V lol. I'm not sure about many fast switching actuators with a freq of 20Hz at 12V. Can a paintball gun even fire that fast?

 

[alec_t]

Instead of a solenoid use a motor-driven cam and cam-follower?

 

[shortbus=]

An electronic fuel injector driver IC should work for this application. They are made to work a higher frequencies than 40Hz, so that should not be a problem. Here is a link to one- https://www.electro-tech-online.com/custompdfs/2012/05/lm1949.pdf

 

[meechee]

yes the motor driven cam is exactly what i planned on doing next. thanks for the replies, i have not scraped the solenoid project yet but its headed to the back burner for now . motor driven seems alot easier and less math. thanks to all who gave me insight and ideas