electromagnetic lock design


by felix_cat
Tags: design, electromagnetic, lock
negitron
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#19
Aug4-09, 08:03 PM
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Definitely you do NOT want a fail-closed door lock for home use. For one thing, it'd be a fire code violation. So, the permanent magnet idea put forth earlier is right out. Your idea could work, but you better be sure of the reliability of your construction; if the coil opens or the power is interrupted for any reason, your door is wide open.
felix_cat
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#20
Aug4-09, 08:05 PM
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eerrr .... you talk about fire codes ....... we don't have fire alarms here ...
berkeman
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#21
Aug4-09, 08:09 PM
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Quote Quote by felix_cat View Post
eerrr .... you talk about fire codes ....... we don't have fire alarms here ...
Well, he also means for basic life safety. I'm assuming the electronic lock is only for access from the outside. From the inside, the door opens with just a turn of the knob, correct?
felix_cat
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#22
Aug4-09, 08:15 PM
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Quote Quote by berkeman View Post
Well, he also means for basic life safety. I'm assuming the electronic lock is only for access from the outside. From the inside, the door opens with just a turn of the knob, correct?
well kind of .. like i said , there are going to be two button behind the door, one for lock and the other for unlock. You can have a knob to pull the door open .....
berkeman
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#23
Aug5-09, 12:54 AM
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Quote Quote by felix_cat View Post
well kind of .. like i said , there are going to be two button behind the door, one for lock and the other for unlock. You can have a knob to pull the door open .....
The behind-the-door ability to exit needs to be 100% mechanical. Quiz Question -- why?
felix_cat
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#24
Aug5-09, 01:06 AM
P: 19
bro ... if you're wondering the 'behind the door' buttons to malfunction, just pull the plug out and the doors open ...

i hate quizzes though .. aint that sharp ....
berkeman
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#25
Aug5-09, 01:30 AM
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Quote Quote by felix_cat View Post
bro ... if you're wondering the 'behind the door' buttons to malfunction, just pull the plug out and the doors open ...

i hate quizzes though .. aint that sharp ....
Not sure I understand your point (and not sure I want to be in a building that you have designed the electronic locks for...).

A big part of being a good engineer is thinking ahead. Safety is a huge part of what you do as a design engineer. If I gave you an interview question to describe to me an electronic door lock mechanism and system, and you fed me what you have posted in this thread, what do you think would happen?

Quiz Question -- Why?
felix_cat
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#26
Aug5-09, 01:52 AM
P: 19
cmon dude ... dont be that harsh ... ive read your post again ...
look yours idea changes my design. I am not making a mechanical lock, its a MAGNETIC LOCK. My design is similar to those that are out there in the market. I gave the link too. I mean guys making those kinda locks aint fooling around .. are they ? .. or are the designs so flawed that they are marketing on the internet ?

I am trying to make one thing different. Normal Maglocks open when entered the right password. Close automatically when the door swings back (door swing back is automatic too). These are the one's which i saw at a university i went to. The different thing im doing is that my design provides security from the outside but easily open from the inside. To make that happen I have to insert 'behind the door' control. AND i am not making the actuator solenoid lock thingys, its a purely MAGNETIC LOCK , no mechanics involved. Please stick to my design if you can ... and i hope i aint getting on your nerves cuz from the way your last post sounded ..... :S :$
dlgoff
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#27
Aug5-09, 06:46 PM
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I don't think you're getting on berkemans nerves. What he is concerned about is safety. Note the rules about posting about dangerous activities:
Explicit "how to" discussions of illegal and/or dangerous activities, or posts advocating such activities, are prohibited;...
Physics Forums Global Guidelines
We don't want to see someone get locked in when there's a fire and the door won't open.
felix_cat
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#28
Aug6-09, 01:13 AM
P: 19
berkman ... im a newbie . ... lets face it ... i dont have answers to ur so called 'quiz questions', rather dealing me with sarcasm you could have some positive attitude and help me. Im in my 5th semester here, not working for a company like you.
I just asked you to help me make a friggin solenoid. thats it .... and my design wont let any one lock em self up. YOU can just pull the plug out and the MAGNETISM IS HISTORY ... for godsake ...

and you josh cum here and sayin ... "we got rules mister. no one dies burning in the fire with a faulty design ... we don help peeple make that kinda stuff here" .... WELL for crying out loud im not making such a thing. Skeptic gave the stupid idea for the PERMANENT magnet design... thats how u make peeple locked in PERMANENTLY... i think i wasted my time coming here on the forums .. buncha fyzists .. buh !
felix_cat
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#29
Aug6-09, 01:14 AM
P: 19
close this thread cuz i aint comin back
berkeman
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#30
Aug6-09, 01:10 PM
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Quote Quote by felix_cat View Post
berkman ... im a newbie . ... lets face it ... i dont have answers to ur so called 'quiz questions', rather dealing me with sarcasm you could have some positive attitude and help me. Im in my 5th semester here, not working for a company like you.
I just asked you to help me make a friggin solenoid. thats it .... and my design wont let any one lock em self up. YOU can just pull the plug out and the MAGNETISM IS HISTORY ... for godsake ...

and you josh cum here and sayin ... "we got rules mister. no one dies burning in the fire with a faulty design ... we don help peeple make that kinda stuff here" .... WELL for crying out loud im not making such a thing. Skeptic gave the stupid idea for the PERMANENT magnet design... thats how u make peeple locked in PERMANENTLY... i think i wasted my time coming here on the forums .. buncha fyzists .. buh !
I ask Quiz Questions all the time, son. It's a teaching/learning tool. As I mentioned earlier, a big part of learning to be a good engineer is learning to optimize your designs. And another part of real-world engineering is thinking about safety and reliability in your designs. You'll come to understand that as you continue in your engineering eductaion.
felix_cat
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#31
Aug7-09, 07:41 AM
P: 19
Well I have got a lot of text warnings. Sorry for my disrespectful attitude Sir.

My request to you is just to look at the following link and explain the structure and design. It would be very thankful,grateful,utmost kind of you.

http://www.sdcsecurity.com/shared/eb..._datasheet.pdf

This is the lock. Please explain why has he not coiled the solenoid directly on to the iron core rather he uses some black material. Could you kindly explain what that black material is and why the solenoid is coiled onto that. Give your guess of the dimensions of the core too.

And the reason why quiz questions are irritating is that you reply the answer to them very late. The other person has project deadlines to meet with if you are not aware.

Regards
berkeman
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#32
Aug7-09, 11:44 AM
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Quote Quote by felix_cat View Post
Well I have got a lot of text warnings. Sorry for my disrespectful attitude Sir.

My request to you is just to look at the following link and explain the structure and design. It would be very thankful,grateful,utmost kind of you.

http://www.sdcsecurity.com/shared/eb..._datasheet.pdf

This is the lock. Please explain why has he not coiled the solenoid directly on to the iron core rather he uses some black material. Could you kindly explain what that black material is and why the solenoid is coiled onto that. Give your guess of the dimensions of the core too.
Sorry, I'm not able to understand that pamplet with just a quick look. Maybe others are able to understand it...
felix_cat
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#33
Aug7-09, 01:11 PM
P: 19
Then do not take a quick look please . this is the forums , you have to help others, give time to them , come on , this is not fair. Berkeman, help please .....
This is a burning issue on forums, not a single forum on the internet deals with designing the electromagnet properly, you have to answer for the sake of science.
Maria2009
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#34
Aug7-09, 07:34 PM
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Quote Quote by felix_cat View Post
berkman ... im a newbie . ... lets face it ... i dont have answers to ur so called 'quiz questions', rather dealing me with sarcasm you could have some positive attitude and help me. Im in my 5th semester here, not working for a company like you.
I just asked you to help me make a friggin solenoid. thats it .... and my design wont let any one lock em self up. YOU can just pull the plug out and the MAGNETISM IS HISTORY ... for godsake ...

and you josh cum here and sayin ... "we got rules mister. no one dies burning in the fire with a faulty design ... we don help peeple make that kinda stuff here" .... WELL for crying out loud im not making such a thing. Skeptic gave the stupid idea for the PERMANENT magnet design... thats how u make peeple locked in PERMANENTLY... i think i wasted my time coming here on the forums .. buncha fyzists .. buh !
I'm very interested! I would love to find out more inforamtion related to this topic. Thanks in advance.
me too, I need more detailed info

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MATLABdude
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#35
Aug8-09, 05:41 AM
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Quote Quote by felix_cat View Post
Well I have got a lot of text warnings. Sorry for my disrespectful attitude Sir.

My request to you is just to look at the following link and explain the structure and design. It would be very thankful,grateful,utmost kind of you.

http://www.sdcsecurity.com/shared/eb..._datasheet.pdf

This is the lock. Please explain why has he not coiled the solenoid directly on to the iron core rather he uses some black material. Could you kindly explain what that black material is and why the solenoid is coiled onto that. Give your guess of the dimensions of the core too.

And the reason why quiz questions are irritating is that you reply the answer to them very late. The other person has project deadlines to meet with if you are not aware.

Regards
Quote Quote by felix_cat View Post
Then do not take a quick look please . this is the forums , you have to help others, give time to them , come on , this is not fair. Berkeman, help please .....
This is a burning issue on forums, not a single forum on the internet deals with designing the electromagnet properly, you have to answer for the sake of science.
We don't give out designs or do your work / homework for you (which seems to be the case here). You might exhort us to spend time and effort upon your behalf (which we do, despite this being 'leisure' or a hobby for all of us) but you'd better do the same. As Jerry Maguire says, "Help us help you!" And in your very first post, you stated explicitly that you didn't want to be spoon fed a solution, you wanted us to do it in such a way(?) that you learned!

Okay, TA in me aside... As a 5th semester student in EE / Electronics Engineering, you should've taken an electromagnetics class. And, as you say, you know that an electromagnet depends upon both the number of turns as well as the current that goes through it:
http://hyperphysics.phy-astr.gsu.edu...ic/elemag.html

Now, you may or may not know that you can multiply the effect of an electromagnet using a core with high magnetic permeability (yes, there are things that are much better than the iron / steel core):
http://en.wikipedia.org/wiki/Permeab...ctromagnetism)

With these in mind, you should be able to figure out how SDC does it. If you have to design your own system for authentication / control and locking (and it sounds like time's running out), don't do it the most complicated and sophisticated way possible (by designing and building your own electromagnet), do it the easiest, and most probably-successful way of doing it: with an off-the-shelf solenoid that pulls / engages a latch, as others have been suggesting!

Is the point of the course to design / build your own electromagnet which can rival commercial products? No? Then breathe, quit panicking, and figure out what you actually have to do (in the time available to you), and not what you wanted to do at the start of the project. This is what I counsel when the students I TA in my final-year electronics design project start freaking out with a month to go.
felix_cat
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#36
Aug8-09, 06:04 AM
P: 19
Firstly its a hobby thing.

Secondly, I have got a design, you just do not go by opposing the design and present a whole new mechanism, you provide small alterations to the design. All I wanted was how to construct an electromagnet that could lift 600lbs with 24/12Volts power supply. Building it from scratch was never taught in the course, only numerical questions where you are given the dimensions already, have to calculate the amperes or turns. That is the reason I came to the forums.

Thirdly: I told you guys that I am in a 3rd world/part of the world where research is at the lowest and people making solenoids and coils by just endlessly coiling the iron core. I do not want that, of course that is the difference between an engineer and a technician. That is 6th grade science stuff and has not changed at the College level either, that flux is proportional to permeability, cross sectional area, current and inversely to length. How technically, keeping in mind the changes in permeability as magnetic intensity increases and the magnetic saturation, am I suppose to design it, that was my problem.
Well thanks a lot you guys, certainly, i think i was not even told what was cooking tonight, talk about being spoon fed.
And Maria baby, do not worry. Daddy is going to figure out soon.


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