i tried to solder some of those 18650s once and that’s when i decided i needed a microwave to make a spot welder out of. almost blew myself up from what i read on the internet, as the heat needed to make the solder stick to the end is near the limit the battery can handle. i learned that when reading about it after i tried it and the solder didn’t stick very good. if i had it to do again i’d put the wires in place on the 18650s and tape the hell out of it with electrical tape for a project like this. i was making a battery pack for a fiber optic splicer and it had to fit back in the same place.
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Yea, I watched some videos a while back about people really messing themselves up trying to do “wood burning” or something with diy microwave oven transformers. Seemed pretty idiotic on their parts not having a clue what they were doing. I feel for them though, serious injuries and deaths too IIRC.
I watched this the other day, curious to confirm that milwaukee 12v batt packs were just a few 18650s connected; he appear to be using a spot welder, diy or other I don’t know. But I see them on amazon for around $100. Just saying. And I don’t know how well they work.
(Time synched for ex. of spot welder).
Quick question - how to I remove these factory “spot welds” properly/safely? Like if I want to take apart the 18650s from the 18V tool battery pack I have to see if they’re charge, etc.?
they should pry loose. then lightly sand them with emery cloth
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Hmm. Sounds…interesting. Unfortunately I’m losing the will to live now. You can all probably hear my brain crackling and fizzing at this point.
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LOL
I’d blame the mice for this. They’re the real root of the problem 
FWIW the 18650s are pretty inexpensive and so I’d probably just buy new cells and save the frustration of using old ones or removing the spot welded tabs. I don’t know about up there in the our neighbor to the north, but down here I like the Molicell P28A or the NCR18650GA and both can be found for around $5 each.
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Ok cool. I’ll get to those things I said I’d try/do this week. Might post here to confirm the right part(s) if I decide to order something.
Alright. Time and money are issues lately. But I also just took a week or so not even thinking about this project. Other than the physical trap aspects; I put some thought into this and poked at a couple things (eg: what type of trigger mechanism, how to set it up, what will hold the hold-down-bar, stuff like that).
I checked the 12V adapter’s voltage when the solenoid fires. It starts at ~11.55V. I checked seven times, after removing the one outlier (I might’ve not read the display right, it’s only there for a second) I averaged the other six and it’s ~9.73V.
I also played with some lower time durations for the solenoid being fired. Starting with 100ms, then 50ms, then 25ms. I settled on 80ms.
Is the solenoid heating up/having issue due to being run “over duty” really a concern for a one-time, triggered even, that’ll only last “x” amount of ms?
My next question might be "Sir, if you have the time, how much would you charge to have this done (coding) for an Arduino Pro Mini, or one of those “NUCLEO-L412KB”? Or perhaps one of your related comments about how you would go about it. (This: “I’d put it all on a small circuit board and probably post 'em online and hope people want the extra ones.”) ← I’ll take a half dozen, please. Haha.
@FieldEffect How’s everything going man? Any harvests inside that auto dry/cure box of yours?
@sfzombie13 How’s the book/writing going?
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should be done by the end of the month, thanx. i can’t wait to get some free time and make one of these for myself. i have all the stuff and am gonna try to modify it for a raspberry pi zero. here i am, getting close to the finish line and looking for another distraction…
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Sounds good, man.
It’s silly, isn’t it. Haha.
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No worries man, glad to see you back at it!
I’m not surprised it’s hard to catch on your multimeter. Even really nice ones are fairly slow. 10V is reasonable, you just want to make sure you don’t reset your Arduino every time it fires. Suppose for a moment it dropped to 1V. What would the Arduino do? It would reset and start the code all over again, because the rat is still dead in the breakbeam, it could fire again, then reset again, then fire again, etc. ad infinitum. With what I say below you’ll get my main concern there.
That’s good at 80ms. I think what I was trying to communicate is that it is over-driving the coil…and while that’s totally OK for a short period of time, especially a one-time event, that is something universally to avoid for a long period of time. If you say, drove it from 48V, it’s possible the solenoid would burn up and melt the wire BEFORE it even finished actuating. It’s over-driven, but not by a crazy amount, so keep the time short. You got the gist of it just fine from the sound of it. I wouldn’t worry about it anymore, just wanted you and anyone else reading my advice to understand that:
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The “5V” solenoid works way better than the “12V” solenoid because it is running several times more power through it. More power mean more force. More technically, it’s actually the current increase that yields the force increase, as I attempted to elaborate on before, but power is equally accurate and perhaps more relatable.
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This is OK, but should be done with the knowledge that you can’t do that forever, and should minimize the operation time as much as possible. You’re getting 5 horsepower out of a 1 horsepower motor so to speak, you can’t run it that way long.
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The actual limit here is how hot the wire and metal components can get before it stops working (burnt enamel wire, permanently magnetized components) or presents a fire hazard. You’re not in that territory, but I didn’t want what I said to be taken as gospel, it depends on the situation. E.g. if this was going in an airplane, or a rocket, or in a hospital, there would be no overload situation ever tolerated ANYWHERE. The solenoid to actuate your rat trap would be 10x bigger and run at a fraction of it’s rated power. A rat trap, with a small battery and especially a fused battery - I’m not worried.
I really hope what I type here is relatable and helpful. It’s difficult to provide consise information that is also technically accurate, especially targeted to people that don’t have much background in the topic. I will say, you’ve done an admirable job digesting what I have presented and asking excellent questions 
I am popping beans right now for my '23 season. I haven’t played with the drying cabinet since November when the last herb came out of it. I’m going to revise the user interface a bit, displaying simpler information, but I was very happy with my VPD control system as described in the last few major posts I made there. It turns out that’s effectively how the Cannatrol works afterall, and perhaps taken a step farther in my case; so that’s a gratifying discovery. My logic was solid, nice to see it independently proven out.
Regarding this question, I’m probably not interested in doing that for money, but perhaps we could work something else out, either charitable or non-monetary. I’ll PM you.
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Ok, that makes sense. And yea, a “fault” of some sort where the trap would keep thinking it needed to fire again, or stay actuated, was a concern of my too (before).
Damn. Hah. That’s hot.
I did consider buying another adjustable 12v power supply to try out with my 12V solenoid (I might have mentioned this) that went from 12V to 18V and also up to either 3A or 5A - I can’t remember. I figured (a) maybe the “available” extra amperage would help, or (b) maybe I could turn up the voltage from 12V to say 14V or more and see if that helped. But anyways…
I think I’d “guessed” it was the lack of adequate current that was responsible.
This I understand, for sure.
Very helpful. I understand the difficulties in explaining. Thanks.
Nice. Look forward to see what you come up with for any of those vpd related projects.
Ok, thanks.
4-6 more dispatched in the last couple week or so. Large, one particularly big. Also was able to identify a burrow and do some “exclusion” work for a neighbor. People don’t realize how serious a problem these pests are.
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I can confirm vouch for the theory behind the concept of this. (Not talking about the devices, just the concept being used). From absurd amounts of time observing their behaviors.
Also, the snap trap used in this (the “new zealand”) one, finally, something with enough power to inta-kill, rather than inconvenience them for a minute while teaching them/others to avoid them.
It’ll probably never be available outside NZ and USA… or maybe I should say it won’t be available in CAN.
Edit: I have to add, that Shawn says on a couple ocassions that “this trap is too powerful” or “the springs are too strong”. Shawn is ignorant, in this regard. The trap is designed by/for people who are trying to eliminate menacing pests. It’s not designed with “cute, advertising friendly” videos in mind, or catching rats, that you allow to populate, and then releasing them a kilometer away for someone else.
Being hard to set, is one thing. Too strong, is another (inaccurate) thing.
That’s all.
Well, at least I learned something about electrical/electronics engineering, and got a better understanding of the depth, and the amount of “things” that can be involved with it.
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The rodent activity is picking up in the area, again. I’m honestly starting to lose the will to combat it, and not having time. I just hope we’re able to move from this area fuckin’ asap.
Is there a thread here where those who’re diy’ing some type of environmental controls would share their work all in one place? I’m curious how many people here (a) have the skill/ability to, and (b) are doing so.