My solenoids arrived for electric push button cocking mod

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Z

zebra

Member
Sep 29, 2015
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New York
My solenoid finally arrived from China today so I can attempt a mod to replace the side-lever on one of my bullpups with a conveniently located micro switch to operate a push / pull solenoid. 

Check it out:


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The front mini solenoid is the typical $10 eBay job with 10mm of travel. It would have no chance of cocking an air gun but will probably be fine for an electronic trigger mechanism. 

The big solenoid has 35mm of travel in the piston which is just about enough to move the pin that is currently operated by my Mutant's side lever.

Both solenoids run off 12v DC which is a good bit more than you get from a typical AA battery. I was going to use the 12v battery from my cordless drill but then I found these mini A23 12v batteries which I will test to see if I can save some weight. The aa battery in the pic is for scale to show how tiny the a23 batteries are. Approx half the length but the same diameter as a aaa battery. 

When I tested the big solenoid manually with my drill battery, the piston shot out with considerable force on the edge of my desk and smacked me in the Crown Jewels which quite literally left me speechless for several minutes. See what I have to go through in the name of science!
 
For a battery pack, take a look at a RC car pack made for mini-sized vehicles. My wife and I recently closed up shop on a successful RC battery business so I am very familiar with the product line. If you have room, look for a 1500mAh, 3S, 12.6 volt LiPo battery from smc-racing.net. If the physical dimensions work for your project, the battery I noted is high quality and very reasonably priced.
 
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I have safely tested the equivalent LiPo battery pack I noted above at a constant discharge rate of 30-Amps from full state-of-charge to empty. Larger capacity packs can sustain discharge rates substantially larger, but then the pack dimensions are physically larger also. I cannot imagine the solenoids requiring discharge rates anywhere near this high. Were the solenoids provided with a specification sheet that listed their Amp requirements? 
 
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It did comes with what I think is a spec sheet but it was in Chinese so it could have been telling my fortune for all I know.

The mini 12v battery did operate the solenoid but I only did a quick and dirty test so far. I have no idea how many cycles I would get or if it provides enough force to pull back the Mutant hammer yet.

Those mini 12v batteries are so cheap, small and light, it would be no problem to wire up 2, 4 or even 10 to work in parallel if needed. Failing that, the 12v battery from my drill will do the job. It's not as small and light but it's still acceptable, rechargeable and heavy duty enough. 

I am going to check out the battery pack that airgunshooter mentioned too. If it is small and light enough, it could be a good option. At the end of the day, the mod is pointless unless that battery lasts for 200-300 shots as a minimum before recharging is needed. Less than that and it becomes too much hassle.

It sounds like some of you guys are much better with electronics than me. I can wire up simple circuits and solder wires or chips to boards but I don't have the knowledge to do much more without help. I may have to pick some of your brains on this one...

I was thinking of keeping it as simple as possible. I.e. Battery - micro switch - solenoid - spring return. 

 
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"AirGunShooter"I have safely tested the equivalent LiPo battery pack I noted above at a constant discharge rate of 30-Amps from full state-of-charge to empty. Larger capacity packs can sustain discharge rates substantially larger, but then the pack dimensions are physically larger also. I cannot imagine the solenoids requiring discharge rates anywhere near this high. Were the solenoids provided with a specification sheet that listed their Amp requirements?
Click to expand...
Need to point out that there is a difference between a lipo rated to pull for example 20C and an off the shelf alkaline battery such as the A23.

https://www.commonsenserc.com/page.php?page=c_ratings_explained.html
 
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"fe7565"
"AirGunShooter"I have safely tested the equivalent LiPo battery pack I noted above at a constant discharge rate of 30-Amps from full state-of-charge to empty. Larger capacity packs can sustain discharge rates substantially larger, but then the pack dimensions are physically larger also. I cannot imagine the solenoids requiring discharge rates anywhere near this high. Were the solenoids provided with a specification sheet that listed their Amp requirements?
Click to expand...
Need to point out that there is a difference between a lipo rated to pull for example 20C and an off the shelf alkaline battery such as the A23.

https://www.commonsenserc.com/page.php?page=c_ratings_explained.html

Yes, I am aware of that. Thank you. 
We tested and sold thousands and thousands of RC LiPo battery packs.

Click to expand...
 
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