Cell Phone Controlled Door
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Hello everyone, Here's my new project - http://ashishrd.blogspot.com/2007/07/cell-phone-controlled-door-latch.html[^] .. Its a DTMF decoder circuit which allows me to open/close the front door of my house with any telephone. I just dial into the base station and a Nokia 1100 auto answers the phone call. Each function is just a matter of pressing the appropriate number on the phone and the DTMF chip decodes it (via a plug in hands free) and sends output to a transistor which controls a relay. I've built a solenoid controlled door latch which is also activated by a relay on the DTMF decoder circuit. The other relays can be used for controlling other appliances...but I'm not using them at the moment. Anyway, be sure to watch the video. :) Hope you all like it, Ashish
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
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Hey - pretty neat project Ashish. I tried a few years ago to work on a couple of hardware projects and they always end up as software only (on a PC). *sigh*
Glad you liked it..many of my projects are a combination of hardware and software...but this door project has nothing to do with software..its all electronics. :)
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
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Hello everyone, Here's my new project - http://ashishrd.blogspot.com/2007/07/cell-phone-controlled-door-latch.html[^] .. Its a DTMF decoder circuit which allows me to open/close the front door of my house with any telephone. I just dial into the base station and a Nokia 1100 auto answers the phone call. Each function is just a matter of pressing the appropriate number on the phone and the DTMF chip decodes it (via a plug in hands free) and sends output to a transistor which controls a relay. I've built a solenoid controlled door latch which is also activated by a relay on the DTMF decoder circuit. The other relays can be used for controlling other appliances...but I'm not using them at the moment. Anyway, be sure to watch the video. :) Hope you all like it, Ashish
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
I'm sure hoping you're checking the number calling or otherwise the robbers will have it easy with a phone call. :-D
Cheers, Mircea "Pay people peanuts and you get monkeys" - David Ogilvy
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Hello everyone, Here's my new project - http://ashishrd.blogspot.com/2007/07/cell-phone-controlled-door-latch.html[^] .. Its a DTMF decoder circuit which allows me to open/close the front door of my house with any telephone. I just dial into the base station and a Nokia 1100 auto answers the phone call. Each function is just a matter of pressing the appropriate number on the phone and the DTMF chip decodes it (via a plug in hands free) and sends output to a transistor which controls a relay. I've built a solenoid controlled door latch which is also activated by a relay on the DTMF decoder circuit. The other relays can be used for controlling other appliances...but I'm not using them at the moment. Anyway, be sure to watch the video. :) Hope you all like it, Ashish
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
The following things need to be taken care of right? 1) When a mobile runs low on charge and during blackouts there should be an option of battery backup on the door. 2) Mobile Thefts and Illegal SIM duplications are quite common. The door should have resilent checking against a secondary check.
Vasudevan Deepak Kumar Personal Homepage Tech Gossips
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I'm sure hoping you're checking the number calling or otherwise the robbers will have it easy with a phone call. :-D
Cheers, Mircea "Pay people peanuts and you get monkeys" - David Ogilvy
Mircea Grelus wrote:
will have it easy with a phone call
No. It might not be that way. The actual trick is the mobile device must be in the neighborhood of the door. Otherwise, implementing security is a big issue. Am I sounding logical, Ashish?
Vasudevan Deepak Kumar Personal Homepage Tech Gossips
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Mircea Grelus wrote:
will have it easy with a phone call
No. It might not be that way. The actual trick is the mobile device must be in the neighborhood of the door. Otherwise, implementing security is a big issue. Am I sounding logical, Ashish?
Vasudevan Deepak Kumar Personal Homepage Tech Gossips
I don't get it. Isn't the purpose long distance? Like "Did I really close the door when leaving for work today today? Just to be sure I'll call home and lock it." If you have to be near, why not just simply use a remote control? [edit] and also, if you're near the door why call? Isn't it easier to use the key. [/edit]
Last modified: after originally posted --
Cheers, Mircea "Pay people peanuts and you get monkeys" - David Ogilvy
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I don't get it. Isn't the purpose long distance? Like "Did I really close the door when leaving for work today today? Just to be sure I'll call home and lock it." If you have to be near, why not just simply use a remote control? [edit] and also, if you're near the door why call? Isn't it easier to use the key. [/edit]
Last modified: after originally posted --
Cheers, Mircea "Pay people peanuts and you get monkeys" - David Ogilvy
Yeah, the purpose is long distance. Creating a password could be a good idea. Right now, my phone number is the only password I've got. If someone discovers that phone number..and knows which keys unlock the door..can easily open the front door of my house. Fortunately, no one knows how to access it. :)
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
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Yeah, the purpose is long distance. Creating a password could be a good idea. Right now, my phone number is the only password I've got. If someone discovers that phone number..and knows which keys unlock the door..can easily open the front door of my house. Fortunately, no one knows how to access it. :)
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
Don't you have a rule in your phone to Auto-Answer only allowed numbers? That way they'll have to be calling from your mobile, otherwise the phone will not answer.
Cheers, Mircea "Pay people peanuts and you get monkeys" - David Ogilvy
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Yeah, the purpose is long distance. Creating a password could be a good idea. Right now, my phone number is the only password I've got. If someone discovers that phone number..and knows which keys unlock the door..can easily open the front door of my house. Fortunately, no one knows how to access it. :)
Time flies like an arrow; Fruit flies like a banana. Ashish Derhgawen - http://ashishrd.blogspot.com[^]
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The following things need to be taken care of right? 1) When a mobile runs low on charge and during blackouts there should be an option of battery backup on the door. 2) Mobile Thefts and Illegal SIM duplications are quite common. The door should have resilent checking against a secondary check.
Vasudevan Deepak Kumar Personal Homepage Tech Gossips
OK, you;ve already indicated you want to create a dtmf "password" system for your door. If you do that ( shift register and comparator and binary thumbwheel awitch gang are the components), throw a flipflop which fires and keeps the system from operating after 2 or three attempts, waits 10 seconds and resets. Brute forging a 10 digit number is trivial because modern computers can run through that many numbers in 10 secs or so. Brute forcing a 10 digit number with 5 secs between guesses will take s/t like 400 years. Aw heck, just the dtmf encoding of a 10 digit number will take 2 secs as each pulse is .1 sec and there should be a .1 sec space between. Just make the fail action be to wait a few secs. So, the point is that your system should be set such that making the call allows one to enter the codes, not that making the call performs the action. I've seen a number of dtmf devices for the home over the years. Now that one can put a webserver on a chip, the trend is browser for remote control. But at one time telephone control of devices was a big deal. Real cool hack btw! Cheers -sam