This project uses a Dallas iButton to operate an electronic lock. Have a look at the full article for lots of detail and project source code to build your own.
"This electronic lock can be used with any type of iButtons you may already have, since the only thing needed is the internal serial number, that’s different for every iButton. The command used to read the serial number is the same for all iButtons. The iButton family code that goes with every iButton, can be anything and is calculated as part of the whole serial number. We must also notice that DS1990A series iButtons are the cheapest. This electronic lock designed to work stand-alone and it’s easy to construct. What the user sees (outside of the door for example) is a iButton socket and a led. From inside the door, we can open it using a simple push button. For the actual lock of the door a solenoid and a bold are used. Solenoid must be rated at 12Vdc. iButtons serial numbers stored in memory can be removed and updated when needed. One master key is used to manage the rest of them. Totally a number of 9 different keys can be stored in memory." 
iButton Electronic Lock
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It is a wery good ideea, but where I can get the program from AT89C2051?
Please help me! I want to put it to work…..
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where I can get the program from AT89C2051?
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Hi Vikram,
Please click on the link to go to the full article, the code is available there.
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hi alan, can u give me the component list for this project (i-button electronic lock) tQ
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Hi Ian,
There are more details in the original project location just click on the link in the article. It looks like the original site is down at the moment though…
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hello,
its a nice idea sir but i want to put it to work so i need the PCB layout…plz help me:)
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I am not sure if a layout was developed. You can look at the full article by clicking on the link. Looks like there are some document downloads for this project. A layout may be included in one of them.
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hello pratiba
do you already get the pcb layout for dis project?
im sure that article don have that..
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hello…
ectually my group have doing this project right now. But the problem is, we dont have the pcb layout of this project.
do you have any idea?
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Hi Ady,
Click on the link in the article, there is a PCB Layout provided.
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do you mean the article in Electronic Lab?
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the acticle is for keylock project..
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can you email to me the pcb layout. (aredpapa@yahoo.com)
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Hi Ady,
Not sure how the link got messed up, I have found the article and updated the link. Looks like there is no PCB layout made available though.