Arduino Key Lock

Ideas and instructions how you can make your own bondage toys.
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red_bondage
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Joined: 12 Jun 2018, 13:42

Arduino Key Lock

Post by red_bondage »

Hey out there,

what do you think about this contraption?

Basicly it is a microcontroler (Arduino Clone) an RC-Servo, a pice of wire, a 3D printed custum part, and a Powerbank.

The Idea is the following:

The Servo is drawing the wire back, you hold your keyring in the right spot. The wire is pushed back.
Now a Timer starts ...

Last step: The key is released.

With a bit of work the whole setup culd be shrunk to way smaler sizes (especially if you ignore that monster of a powerbank) and maybe use a smaler servo. Such a small box is easy to be placed pretty much everywhere. Maybe with pice of double sided tape, maybe with a screw, or maybe with a piece of string so some kind of lamp (shure: I need to design a propper connector within the next Version)...

If you exchange the powerbank for an USB adapter this thing can have a (close to) unlimited runtime :twisted:


My further plans:
- overall better build quality --> This is just a proove of concept
- add a box to cover everything
- add a count down timer (bright red Leds)
- mount everything on a "real" PCB
- maybe add somekind of "input" to extend the timer. (Sound, or maybe the push of a Button)
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arduino lock.jpg
lj
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Re: Arduino Key Lock

Post by lj »

welcome to the forum and BoundAnna :D

you ask for an opinion...

what happens when the power supply runs flat?

what happens when the servo jams up and won't move

what happens when the microcontroller says "naaah, don't want to play anymore?"

unless you have an emergency back-up that has nothing to do with your gadget, you may be spending rather more time in bondage than you want, possibly permanently :shock:

when designing bondage equipment, always look for possible failure modes, just like the three I listed above (and I could list more...)

One of the reasons using an electromagnet to hold the keys is safe(well, almost) is that any failure releases the keys. One thing to bear in mind, a permanent supply will stay on forever, or until the mains supply fails, which could be years. A battery always runs flat eventually, so don't use a battery with more capacity than needed for your session. And always make sure the keys are heavy enough to pull free from the electromagnet - there is something called remanent magnetism, a fairly weak memory of the magnetic pull stored on the core of the magnet, enough perhaps to retain a single key. Always test your release before committing to the bondage.

Not trying to put you off, but we prefer our forum members to keep coming back !
be a switch, double the fun :-)
red_bondage
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Re: Arduino Key Lock

Post by red_bondage »

Thanks for the welkome

Shure, this is without a dought not a fail-proof system. And it would be madness to use this gadget without additional backups. And ofcause totaly independent ones.

Do not worry, I will not get myself into dangerous situations. If I do anything I have always my private, and personal backup right arround me (I talk about my gf)
I know there is a security benefit for the magnetic version, but i like the simplicity and the flexebility this offers.

The argument: Magnetic stuff has its benefits and is therefore safer is correct. Hmm maybe I find a solution for that as well ...
thatthat21
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Re: Arduino Key Lock

Post by thatthat21 »

I see every one all ways talking about how they use the mag locks and it just takes this and that.... I would really like to see a write up on how to use the mag locks and use them safely as well. Part of the write up should be parts as well, and I know we are all over the world so would be nice to have all power sources (aka 220 and 110) listed as how to use as well. I have ways to turn things on and off via many options, some programmed and some manually, just need to know how/where to get the mag locks working and working safely. I hear about heat and fail safe options and things like this all the time so just want to make sure that the right things are used.
red_bondage
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Re: Arduino Key Lock

Post by red_bondage »

Personally I am to scared to rely on any single escape methond. Now matter how "safe" and "reliable" is is suposed to be.

In the past I have allways used 3 ways to "escape"

1 - a precise timed escape like the contraption shown above, or some kind of electro magnetic solution

2 - an additional time release, independet from the other --> Ice in almost all of the cases. This is pretty reliable but hard to time. I have always aimed for "a bit longer" than release 1

3 - an emergency escape route. I mean something like a key on a string, which can be pulled at any time - but pulling the string activates some unwanted consequences. (like tipping over your fafourite bottle of whiskey, or activating the paper shredder destoying some money. In this case something anoying, and time consuming to clean up works better than something that "just" costs you some money. (at least for me).
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Sir Cumference
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Re: Arduino Key Lock

Post by Sir Cumference »

red_bondage wrote:Thanks for the welkome

Shure, this is without a dought not a fail-proof system. And it would be madness to use this gadget without additional backups. And ofcause totaly independent ones.

Do not worry, I will not get myself into dangerous situations. If I do anything I have always my private, and personal backup right arround me (I talk about my gf)
I know there is a security benefit for the magnetic version, but i like the simplicity and the flexebility this offers.

The argument: Magnetic stuff has its benefits and is therefore safer is correct. Hmm maybe I find a solution for that as well ...
Welcome

Servos are great for a lot of things (they are quite strong), but they will typically stay in position should the power fail.


A small solenoid instead of the servo would make it "fail safe" in case of loss of power.
My take on it is here.
Subject: Arduino key dropper:
The solenoid is from an old relay, and draws less than the 40 mA an arduino pin can safely deliver.

The key hangs from an iron key ring and is so heavy, that the electromagnet can just hold it. This reduces the chance that the remnant magnetism will hold it once the current is switched off.
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7020C34E-5AA8-4EB2-A033-C0E8F7F7C519.jpeg
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~
red_bondage
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Re: Arduino Key Lock

Post by red_bondage »

Well I have thought and experimented with that type of constuctions as well.

some of the things that I do not like about:

1 compared to a "Servo" dropper they are not flexible enought.
2 bigger ones are impossible to operate via (small) batteries
3 some of the advertised "additional safty" is not really there. Example: The whole thing about: Battery will run out, so key will drop.


a bit more explanation:

1:
Your version is great to do the one job it is built for. But what happens if you want to use a different setup next time? Maybe you want to drop a second key, or you want to release a pair of sissors. (Really dropping them might be a bad idea.) The Servo version is dooing all of that without any reprogramming, fiddeling again with electronics or anything.
I have testet the flimsy version above with 5 - 250g

2:
The moment the magnet gets bigger, you need waaay more power. And is is getting even more difficult to really build the additional safty in the system. Shure you can use high powered LiPo cells or something like that. But that destroys the whole "small and easy" thing a bit.

3:
What happens if the batteries run out?
Well if that is the only option of escape I will be pretty stuck. But is your version really better?

Accorting to an online source a standard (energizer classic AA) AA Battery can deliver 45mA for approx 35h. (https://anon.to/QVIeKI)
After that 35h the battery has reached 0,9V. and it is not shure if the key will drop at that level. It might take even longer. Have you tried that?

I know it is possible to build some additional safty in by cutting of the power after the battery level reaches a predefined level.
And shure, there are many additional options to increase the power consumption of the whole system. The simplest might be to just add a small lightbulb from a low powerd flaslight directly to the power pack) And by the way: no LEDs are not alwys a better choice 8)
But all of that is not that easy done, and it reduces the flexibility of the whole system even further.
And building all that extra "security" increases the room for error. It is not that fun either if the key is dropping after 60 min, but you aimed for 120 ? ...


I thinker a bit more with the Servo version. Beeing cautios of the fact that that version is only 95% secure. Heaving real alternatives in place if the 5 % happens ...
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Sir Cumference
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Re: Arduino Key Lock

Post by Sir Cumference »

That is not correct.
The Atmega chip has “brown out detection” that shuts it down quite a bit earlier.
As far as I know, the factory value is 2,7 V.


And it must as always be experimentally verified how it will behave in the actual setup.



- You asked for opinions, you got opinions.
- the task you outlined was “safe way to drop a key”, not “how to drop something heavy”
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~
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