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solenoid circuit

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keith wedgwood03/08/2020 23:02:32
15 forum posts

hi i am wanting to run a solenoid to trip a trigger sear on an air rifle.

how would i do this.

keith wedgwood03/08/2020 23:51:40
15 forum posts

sorry posted in wrong forum . moderators please move to help wanted

many thanks

John Haine04/08/2020 06:36:49
3270 forum posts
175 photos

Battery, switch or button, wire, all in series.

SillyOldDuffer04/08/2020 10:07:03
Moderator
6186 forum posts
1345 photos

Not sure a solenoid is ideal for this application. Solenoids pull a magnet into a coil with a snap action which takes a fair amount of current, meaning a big battery. Is jerking a trigger bad for accuracy?

Unless the air-rifle must fire as soon as the solenoid operates¹ I'd be inclined to look at a small motor turning a screw thread pulling a nut back against the trigger. It would go whirr-bang instead of click-bang if that's OK. Provided speed isn't an issue, the screw's mechanical advantage allows the pull to be done by a small motor and ordinary battery. But it's a bit slow.

As John says the electrics are a simple series circuit. The motor version might be improved by a reversing switch, but the trigger pull screw could be rewound manually. I'd find the mechanics of the trigger mechanism more bother, needing some sort of stand or attachment to the rifle.

Health & Safety Note. Visiting one of Her Majesties Royal Fleet Auxiliaries, I noticed painted lines on the deck and went inside them to read a RED notice. It said, 'Gun may Traverse and Fire Without Warning'. A fully automatic radar operated gatling gun, shoot first and ask questions later. I like to think it was switched off...

Dave

¹ Moving target engaged under RADAR control?

Robin04/08/2020 11:48:28
avatar
353 forum posts

The testers of safety glasses always seem to fire the test ball gun using solenoids. The solenoids are invariably huge and there is a monstrous electromagnetic pulse that freaks out everything electronic nearby. Do you really need a fast response because a little gear motor wired for one turn would be an awful lot less fraught?

mgnbuk04/08/2020 13:45:02
792 forum posts
61 photos

Not sure a solenoid is ideal for this application. Solenoids pull a magnet into a coil with a snap action which takes a fair amount of current, meaning a big battery.

OP says he wants to trip a sear in the trigger, so short movement & low pressure required. No need for large solenoid & big battery. There are already "electronic triggers" on production rifles (Daystate) that use small rechargeable batteries that apparently require very infrequent charging, which does not suggest a high current solution.

Unless the air-rifle must fire as soon as the solenoid operates

That would be the general idea. When I get the sight picture "just so", I want the pellet on it's way straight away with just the application of a slight further pressure on the trigger, not for the gun to fire sometime arbitrary time later.

Is jerking a trigger bad for accuracy?

Triggers are generally "squeezed", and definately not jerked. Well not if you want to hit what you thought you were aiming at ! "Nice" triggers are often "two stage", in that there is a small movement up to a noticable increase in resistance, then just an increase in pressure from that point releases the mechanism. All very controlled & predictable. I don't think that a solenoid would replicate a two stage trigger, though from what I have read the Daystate trigger is supposed to work well. Reading about Daystates is as far as my wallet will allow, though.

Nigel B.

SillyOldDuffer04/08/2020 14:50:25
Moderator
6186 forum posts
1345 photos

Posted by mgnbuk on 04/08/2020 13:45:02:

... OP says he wants to trip a sear in the trigger, so short movement & low pressure required. No need for large solenoid & big battery. There are already "electronic triggers" on production rifles (Daystate) that use small rechargeable batteries that apparently require very infrequent charging, which does not suggest a high current solution.

Unless the air-rifle must fire as soon as the solenoid operates

That would be the general idea. When I get the sight picture "just so", I want the pellet on it's way straight away with just the application of a slight further pressure on the trigger, not for the gun to fire sometime arbitrary time later.

...

Nigel B.

Air-rifles have moved on since I bought my Trusty Webley pistol. It was a long time ago, back when Wireless Sets had Mullard Valves in them!

daystate.jpg

Gosh! Times change.

I was thinking of a 1kg pull solenoid lock like this.

solenoid-electric-door-lock-12v-1700ma.jpg

The example has a 12V coil demanding 1.7A which would need a high-current battery, though only in a short pulse. Li-ion battery rather than CR2032 but do-able!

I wasn't thinking of human shooting either. Last time I fired my pistol it was in pitch dark for taking a pellet in flight flash photograph:

img_1286_modified_1.jpg

Although the gun was pre-aimed I had to find the trigger in pitch darkness, and an electronic trigger would have been safer!

Never heard of Daystate before. Very educational this forum!

Dave

Edited By SillyOldDuffer on 04/08/2020 14:52:08

Grizzly bear05/08/2020 19:27:30
249 forum posts
8 photos

For info only: **LINK**:

Regards, Bear..

keith wedgwood05/08/2020 21:25:06
15 forum posts

many thanks as i have a very basic under standing of electrical circuits. i left school in 82 so am a bit rusty. lol

pgk pgk05/08/2020 21:36:25
1888 forum posts
288 photos

Two stage trigger action makes me wonder if the dodgy option of preloading the trigger with a spring would allow a smaller solenoid to complete the action?

pgk

keith wedgwood05/08/2020 21:54:59
15 forum posts

there would be no need as the micro switch effectively works as a two stage trigger

Former Member06/08/2020 12:02:06
1 forum posts

[This posting has been removed]

Frances IoM09/08/2020 19:55:23
804 forum posts
26 photos
new to this forum but old form of link spam

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