Tuesday, July 17, 2007

Cell Phone Controlled Door Latch


Download Video (1.78 MB)

I’ve been reading a lot on how DTMF (Dual Tone Multi Frequency) tones work over the last couple of weeks. I’m sure you’ve noticed that when you press the keys on a standard telephone keypad, an audible ‘beep’ is generated. These beeps are actually the combination of two distinct frequencies. For example, the tone you hear when you press the number ‘9’ on a telephone, is actually a combination of a 1447 Hz and 852 Hz signal. In a telephone exchange, these signals are decoded by a computer which finally connects the dialer to the designated phone line. For example, the tone of 1447 Hz and 852 Hz will be decoded as binary ‘1001’. In this project, I have designed a simple DTMF decoder circuit which allows me to control appliances in my house from any place on Earth using a telephone.

I always wanted to be able to control things such as air-conditioners, lights, etc, remotely…but I never thought about putting the front door of my house under remote control until I saw this “knock to open” door hack on Hackaday. It’s a door that will unlock when the correct knock pattern is performed. After being inspired by the mechanical door opening system in that hack, I decided to do something similar to allow me to open my door with a cell phone! I mean c’mon, door locks with keys are obsolete..everyone uses them..they’re so old fashioned! They’ve been around for over 4,000 years. Yikes! It’s time for a little change.

This project would have been much simpler if I had an electronic door lock…but I didn’t! They’re expensive, so I didn’t want to buy a new electronic door lock. I wanted to open the front door of my house without “seriously” modifying/replacing any door components. I thought about using a servo/stepper motor to twist the door knob on the door, but their control circuitry is slightly complicated if you’re not using a microcontroller. So, I decided to use a simple, 24VDC, “pull solenoid”. They don’t have any complicated control circuitry and you just have to supply the required voltage to make them work. I simply fastened the solenoid to the door knob with a metal wire. When the solenoid is switched on, its linear motion twists the door knob and opens the door. Positioning the solenoid properly was probably the only mechanical challenge in building this door opener because the force applied by a solenoid, is theoretically inversely proportional the square of the length of the air gap. Thus, strongest force is generated when the air gap is smallest.



The second part of this project was to build a DTMF decoder circuit. I used a CM8870PI tone decoder IC for doing this. The circuit I have built is fairly simple, and can be used for controlling up to four devices. If you want to control more than four devices, check out this circuit. I had a Nokia 1100 cell phone lying around with a hands-free accessory which was rarely used. So, I hacked its hands-free accessory and connected it to the circuit (I just cut the wires which went into the earpiece). That’s about it! To control things in the house, you just dial into the base station and the 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 and sends output to a transistor which controls a relay. To open my door, I just dial the phone, enter the magic code and voila - Alohomora! Watch the video above. :)





Now I’m thinking about building a password protected door by placing a keypad outside my house which will generate DTMF tones. A circuit on the other side of the door will check the numbers entered, and if the password is correct, it will open the door. However, there’s one little snag. Any nasty programmer would just love to use a computer to generate DTMF tones and crack the password using brute force…I would. :)

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217 comments:

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jeff said...

Maybe for your password protected door you could use a tone dialer like the ones in old redboxes

Chris said...

Just leave your key lock in place and lockout the keypad after a number of failed attempts :)

Ashish Derhgawen said...

Yeah, that's exactly what I was thinking. :)

Emanuel said...

Or have it set on a timer System, so that after 3 failed attempts it will lock you out for X amount of time. That will help against any one thats smart enough to make a brute forcer.

Alan Parekh said...

Well done!

rob said...

think asterisk man

then you don't need a extra cell phone account for this sort of thing and you can have many extensions directed to different devices

very sweet I think I'll be adapting it myself I have a electric door lock already was going to do a key fob for it but this is even better

Anonymous said...

if there is no network for x or y reason,you cant come in!

Ashish Derhgawen said...

If I can't get in for x or y reason..I can always use regular keys, can't I? :)

Nate said...

To be honest, I don't see how this would be commercially viable. Here in the USA garage doors use RF with advanced security. The code in the transponder is synced with the code in the receiver, and if you press the button they move together in excess of 128 bit cyphers. The same thing with really fancy Mercedes.

Perhaps a phone with RF, such as nextel would be easier. Unless your sending 128 bit cyphers through cell phone signal, hackers can pick up the signal and easily figure out your code. Brute force isn't necessarily needed for wireless, scanners do a much better and faster job.

robomaniac said...

If you read Hackaday.com you probably heard of the GM862 Cellular Quad Band Module. That is a serious little awesome gadget! You could control the door and take pictures of inside your house if someone break in! The idea to connect to the hands-free is brillant! I have a electric door opener (114$ cdn) and want to implant the RFID first! Keep up the awesome work Ashish!

Jerome

Adam said...

I agree with Nate, rarity/novelty would be the only secure thing about this device.

Even if your cell signal is encrypted, with the DTMS base, you've still got a crappy key without an obscene amount of numbers. And if you can remember an obscene amount of numbers, where are your keys?

Wasn't "hacking" originated by getting free long distance emulating DTMF tones? Ironic that a "hacker " would use them to secure his home.

Prashant said...

Oye dude get rid of that craptastic header on your blog! :-P

And good project, btw!

rob said...

sorry Nate but most cell phones today are digital and use higher than 128 bit cypher already

so if you had this tied to your home phone it could be prety sweet but waiting for 4 rings or something could suck

thats why I say tying it in with asterisk or something could be very useful

Anonymous said...

Would this work with a landline phone ? For example, could you cut the ends off the phone cord and use it that way?

Ashish Derhgawen said...

Yeah, I was originally using this circuit with a landline phone.

Vinnie said...

Maybe if you upgraded the door to an electronic door opener you would have better luck with the password coded idea you want to run to open your door.

computer-stuff said...

thats all good but a sledge haammer and freeze on would go stright through it.try using a closed used group on the nokia makes it alot harder to crack as it gives the same effect as two pass words.

Anonymous said...

Love this! want to build it but:

The circuit drawing does not look complete. There are parts I can see in the picture (like the 3 blue things and big capacitors). That are not on the drawing??? Can you post a complete circuit?

Andrew said...

Great little project, nice and simple. Personally for me pasying 40c for a phone call everytime i want to open a door would get annoying, but for a remote operated system it is great.

For those in paranoia land who are worried about brute force hacking of the dtmf or sniffing out codes ill leave you to it, personally ill just use a bump key and go through the existing lock!!

Michael said...

Add a duration parameter to each digit of the code (ie, less than 1sec, 1sec-2sec, and greater than 3sec). That should sufficiently stymey any brute-forcer.

Anonymous said...

heyyyyyyyyyyyyy......

listen to me, you dont need nothing to do, so only you need setup the cellphone in the circuit with your cell number, so only recognice your own cell phone and nothin more

Anonymous said...

Great project. The super-minimal circuit is really cool.

The "brute-force" concern is way off-track. In the circuit, one button press triggers one solenoid. He's only pressing, say, "3" to get in, not a long code string. The "code" lies in knowing the specific phone number that goes with the door, and that's probably a reasonably large search space.

To brute force it, you'd have to dial a bunch of cell phone numbers and press 0-9 on each. This would take quite a while if it answers on the 4th ring.

Anyway, most door locks are reasonably easy to open and/or decode in comparison. Googling "bump key" and "master key vulnerability" is fairly eye-opening.

Cool project. And the security vulnerability it opens up is, IMO, second-order to how sweet it is to open up your door by cellphone.

Might have to implement this chez moi. Not telling you my address or cell number, though. :)

Ashish Derhgawen said...

"Anonymous said...

Love this! want to build it but:

The circuit drawing does not look complete. There are parts I can see in the picture (like the 3 blue things and big capacitors). That are not on the drawing??? Can you post a complete circuit?"


The 3 blue things are the relays. There are some parts I haven't shown in the circuit diagram..for example, (1) I'm using a 7805 regulator chip for providing a steady supply of 5 V. (2) There's an LED connected to pin 15 of the 8870 tone decoder chip. (3) The big capacitor is a part of a bridge rectifier circuit which converts AC supply voltage to DC voltage. That's it. :)

Anonymous said...

I agree with the "heyyyyy" anonymous comment - set up the phone to only ring when your own cellphone (or anyone else in the house) rings it and then use a microcontroller or something to detect the ringing (or the power going to the vibration motor - then it's silent) to open the door. That way the phone call is not connected and it's free to open the door and you just need to press one quick-dial button on your phone.
The quibbling about security is nonsense - someone would have to really know about your system to even know where to start cracking it and frankly if anyone really wants to get into the house they will use a crowbar to open the door or break a window.
Great project! Well done!
Benjamin Franzmayr

william said...

Hack a day brought me here but I will be back.Keep up the good work!

seesoe said...

may i ask where u bought your CM8870PI from?????

henry said...

you can send the complete cct diagram to henry_dayo@usa.com

Anonymous said...

Love this! want to build it but:

The circuit drawing does not look complete. There are parts I can see in the picture (like the 3 blue things and big capacitors). That are not on the drawing??? Can you post a complete circuit?"

The 3 blue things are the relays. There are some parts I haven't shown in the circuit diagram..for example, (1) I'm using a 7805 regulator chip for providing a steady supply of 5 V. (2) There's an LED connected to pin 15 of the 8870 tone decoder chip. (3) The big capacitor is a part of a bridge rectifier circuit which converts AC supply voltage to DC voltage. That's it. :)

Yes I'm interested in seeing the circuit for the rectifier circuit and where exactly you connected the relays (and what type of relays are suitable). Is it possible to post a complete schematic with parts list? This will help beginner hobbyists like me because when I google on rectifier circuits I don't get parts lists so don't know what type of diodes are suitable, what capacitor to use so that the bumpy wave (by mirroring the sine of the ac power with the four diodes in bridge you get indeed a bumpy dc power wave, but still need a certain capacitor to straighten it. But which capacitor, what value? what voltage?) .

Anyway I would be really happy with a complete circuit+partlist then I definitely want to build this for my door, will sent you pictures :)

Vitalik said...

Could you please tell what number combination do you use to activate something? I see 4 relays, so you have to press "1" for example to activate it? what are keys for each relay?

Vitalik said...

Could you please tell what number combination do you use to activate something? I see 4 relays, so you have to press "1" for example to activate it? what are keys for each relay?

Anonymous said...

http://www.raphnet.net/electronique/electronique_en.php

Most of your projects look similiar to projects on that site

Anonymous said...

The diagram shows two telephone wires. How did you connect the cellphone to those wires? With the handsfree connector?

Isabel said...

Hi...I loved your work...but could you help, please?...I don't know how to program the cm8870...could you send me your program?...thank you and good job..
e-mail: isabel.hanks@gmail.com

Rohit said...

Wow, Ashish - this work is amazing! Have you tried typing your name in google? This work is really incredible...

Anonymous said...

Hey...I really like this...it's really useful.

Anonymous said...

Hi..nice job.i like ur project.
it's really cool.but i am not getting the exact operation of how u r controlling.
when ur in the DTMF mode,TO TURN the device from normal conversation mode to appliance control mode u have pressed '0' on the key pad,and the number say 1 for controlling the device u have given (or) does it depends on number of rings should occur to ON the device,...
yaar iam little bit confused.
can u please help me out.
Email:madhujo@yahoo.co.in,
kondur.madhu@gmail.com

bylle said...

hello! is it possible to have more than one code? you said there that only one number serves as a code for your door... how can I make a code that consists of three or four numbers?

can you help me please?
here's my email: gigi_lao27@yahoo.com
thank you!
btw, your project is cool! I liked it that's why I wanna integrate it in our project... ASTIG!

oly said...

hey i live in the u.k and want to make this.can u tell me where i can buy the m 8870?

Anonymous said...

i have bought all the part and built your circuit perfectly, can you give me some troubleshooting steps. the chip I have is the de one is the pins the same for it I can;t find a datasheet for it thanks for your help
brandon@rockcastlehosting.com

Anonymous said...

Hy Greatwork,

But you are using a Nokia 1100 phone, and it hasn't the auto answer function. How do you manage to get this phone auto answer?

Thank you.

Ashish Derhgawen said...

Are you sure Nokia 1100 doesn't have an auto answer feature? My Nokia 1100 has auto answer..but I think it only works when it is plugged to a headset.

Anonymous said...

Nice....wonder how many innocent people died because you posted these easy to follow directions for any Islamic Extremist to build a command IED on your site. You are obviously a very intelligent person with either, no common sense or no sense of responsibility.

Ashish Derhgawen said...

Thanks for your comment. Read this post -
http://ashishrd.blogspot.com/2007/11/possibility-of-misuse.html

Wilsito said...

Keep up the Good work man, love the projects on here.

b18c5.org said...

I'm so glad I found/bookmarked this site a few weeks ago! Awesome stuff!

SomeDutchdude said...

Good project. I live in an appartment, with an auto door downstairs. Thinking of wiring the circuit to the button. ;-)
Keep up the work.

-greetings,

some Dutch dude. :-D

B said...

here's another good one: http://www.howtodothings.com/computers-internet/how-to-trace-cell-phone-numbers-free
lots of good ideas!

Anonymous said...

i made a eagle cad drawing so that i can create my own pcb for this circuit.pls have a look and let me know abt the mistakes.
http://img257.imageshack.us/img257/4849/12tc3.jpg

and i have some basic doubts(sorry if they sound dumb) in the circuit.
--A0,A1,A2,A3 are the output.what are the codes required to switch them on.
--relay will switch on,once the respective output is on.will this output stay on(high)? if yes how can i reset it.imean can i switch
on and "off" a device?

pls help me
regards

Ashish Derhgawen said...

The only mistake I found was that in your circuit, diode D1 is backwards.

Yeah..you can switch devices on and off. For this circuit, you can use the numbers 1, 2, 4 and 8.

Cheers :)

Anonymous said...

thanks a lot for ur reply.
i'll make the correction and will post the populated board soon.

so 1,2,4,8 are the switch on codes for A0,A1,A2,A3 outputs respect..
then how can i switch the particular outputs off.shld i use sames codes again to rest their status.

and you said LED is connected at pin15.is it between pin15 and ground or supply.

iam sorry for keep asking such silly doubts,but iam trying to clarify myself and to other dumbs like me
:-)

thanks once again for ur effort.

Anonymous said...

i was wondeing if this could be used as a car security system, say your car gets stolen you dial the number and viola your car engine dies out leaving the thieves stranded in the middle of road.

iam a novice , iwould love to build this circuit for my car, does this require any programing of the chip? thanks

firoz said...

well i think it can be done.
say we will take a nc/no relay and wire the cars ignition kill wire thru the NO contact.so when we activate the relay using 8870 IC(NO becomes NC),it will always be in ignition kill mode.until we reset it back.

i too made a eagle cad design.in this design i placed a 7805 and an LED between pin15 and GND.
**i hope ashish don't mind.
http://img207.imageshack.us/img207/5569/12uy2.jpg

regards

kathy green said...

Can this be done with an iPhone?

Ashish Derhgawen said...

Kathy: Yeah, it could. After all, the iPhone is EVERYTHING! :D Well, as long as it comes with a hands-free cable..and has an auto-answer feature, you should be able to do this project.

Good luck!

john said...

Yeah

This is good for our mobiles



Celllular Phones

Sanmati said...

I want to start an irrigation pump using cellphone using DTMF
I am not getting how to connect cellphone to MT8870 DTMF decoder
plz help.
cutting the earphones isn't working.
email M sanjainsuny@gmail.com

rahul said...

I working with robot control using cellphone using DTMF
I am not getting how to connect cellphone to MT8870 DTMF decoder
plz help.
cutting the earphones isn't working.
can u help me out with ckt iam using the simple ckt given in datasheet of MT8870
please send me ur reply on electromania619@gmail.com

ashish said...

i built this circuit yesterday but when i power the circuit my relay( driven from pin 11) is activated,the relay is not switched off with the code (ie number 1).
where have i gone wrong.

lankythoughts said...

I know it is unlikely, but still I hope those ads from the service providers wont open your door or stop your car :-P

Anonymous said...

hey ashish i want to make this circuit....can u give details abt dis circuit? really i m looking forard 4 ue reply

Anonymous said...

hi......
i want to do this project but i cant understand the working of the circuits so plz can you give the detail information and complete circuit so that i can make this project succesfully

so plz reply me quickly

Anonymous said...

hi Ashish,great work,i am a biggner ,i also want to make this,but in ckt u r using headphone wire but in video there is no wire please send me the complite ckt at
sourabh_soni0711@yahoo.co.in
please

Monty Alexander said...

hi dear, nice blog, you have a good knowlege about mobile phones configuration. you will sure made that password protected door.

Matt said...

Very cool!

Anonymous said...

Hi Ashish,

I tried to setup the circuit. But I couldn't power any of leg. I guess I2m wrong about telephone lines. So that I connected the lines from my pc and sent the signals by a software. Can you give some information how you conect the lines and maybe troubleshooting information? Is there a way to check the circuit by a multimeter?

regards

Nanogear said...

Hello,

I did something very similar with an iphone and a DTMF circuit to control a magnetic lock.

If you want, you can watch a video I uploaded in youtube: http://youtube.com/watch?v=x88I8GQlYDs

Anonymous said...

Hi,

I watched that video before, thanks anyway. Could you send your circuit diagram. Maybe I can over come my ptoblem.

nanogear said...

Hello,

The circuit is the same.

Please tell me what is your problem and I will help you.

Ashish Derhgawen said...

Nanogear: You video is really cool! Great job :D

Nanogear said...

Thank you Ashish Derhgawen, you gave me the idea!!!!

Anonymous said...

dude great device but a had a question... How do you configure the circuit to get the code you want.. i mean if i want 1570 to be the code, how should i configure???

Anonymous said...

hey am felix frm kenya. i was just wondering if u can atleast give us details on the operation of the circuit. also if u dont mind give us details on how 8870 chip works and how u programme it. please!!!. nice job keep it up1

Anonymous said...

Hi Ashish's, great post. I found this link while researching how i can use DTMF tones (via a mobile phone)to control relays. I would like to attach a 3G camera phone to a hot air ballon/airship, and use it to monitor traffic. The camera of the phone will broadcast the traffic conditions, and the phone will control relays (to control the flight of the hot air ballon/airship) via dtmf. I was wondering if you can share with me the materials i would need for this project, as well as build instructions. You may e-mail me at mrktn1@yahoo.com as well. Kind regards, Mark Tan

AmrutJ said...

Hey dude, which wire of earphone have you connect to Telephone Line input?

Anonymous said...

hey tell me which wire of earphone to join to decoder ic..actually i m working with MT8870 dtmf decoder ic..pls help..
ninadkhd11@yahoo.co.in

microtech said...

Hai ashish.u hav done a great job by doing that cellphone door lock prjct.
......can u plz help me in connecting the headphones to the 8870 decoder ,cutting the wires is not working.........plz ashish plz help me inb this thing,,giv me a complete idea how to connect the headphones.

nanogear said...

cutting the wires is not working.......

Why not??? You need to cut the wires and then use a lighter to burn the therminals. In that way, you remove some kind of protective paint. So in that way, you now can solder the wires to a better cable.

Anonymous said...

ammm juz read ur journal...i'm worrking on my thesis ryt now...it's kinda similar with you're cell phone controlled door latch, but i'm still thinking if i will juz use a cell phone or a blue tooth device,am..juz wana ask if it's pure device or you programmed these device of yours and wat programming language did you used? and about that magazine that you mentioned cn you send me a scanned copy of it if it's ok with you...tnx. you're help will be highly appreciated

Anonymous said...

ammm juz read ur journal...i'm worrking on my thesis ryt now...it's kinda similar with you're cell phone controlled door latch, but i'm still thinking if i will juz use a cell phone or a blue tooth device,am..juz wana ask if it's pure device or you programmed these device of yours and wat programming language did you used? and about that magazine that you mentioned cn you send me a scanned copy of it if it's ok with you...tnx. you're help will be highly appreciated. My email add is wency_dalumpines@yahoo.com

Anonymous said...

is it pocble to open the door using text msg instead of call?

vikki said...

hey pls send the details and circuits of cell phone controlled door latch...
my id is "vikasnidhi88@in.com"

dagob said...

That's exactly what I was looking for, can you send me more details of the circuit i'm a newbie u can send it to doidaovarrido@gmail.com. Thx in dvance and I think I'm a new fan of yours!

Anonymous said...

hi Ashish,
we are on simillar lines to get our project done. we have read all comments. but we are not getting the way in which the headset is connected to the decoder circuit. pleaseeeeeeeee send the whole circuit to ashishsram@gmail.com

Anonymous said...

i m not able to connect the cellphone output to the dtmf input..
can you explain in detail....
the youtube link is not getting opened....
help me out as soon as possible...

Anonymous said...

can you send me the whole ckt diagram showing the the connenctions from the cellphone's earphone to the dtmf input...
there is some coating on the earphone's wire????
send me at sabanishat@gmail.com

Anonymous said...

what is the substitute of the IC CM8870 because i can't find here in the philippines

allan said...

what is the substitute of the IC CM8870 because i can't find here in the philippines...thanks

Anonymous said...

hi..i'm doing a project same to urs...but with MCU...can you send me the complete schematic diagram of ur work becoz it's kinda blurred in ur post....here's my email add wency_dalumpines@yahoo.com...tnx

Anonymous said...

have u tried doing ur project with MCU???

Anonymous said...

hei need some help here.. we're doing a project about a computer controlled cellphone here how it should work: an inquirer will inquire through text to a certain cellphone no. connected to a PC.. the PC then checks it in the database. and will reply the status of the inquiry.. to the inquirer.. how can make this possible?

Anonymous said...

sir kindly email me pls.. tnx alot..
mdivad_14@yahoo.com
inquirer thing project..

Michael Bass said...

I continue to get the relay to latch immediately upon power up, and each output Q1-Q4 is high, even without any signal connected.

Are there any corrections to the circuit as you show? I have tried 5 different 8870 chips, so it is unlikely they are all bad.

I am using a 9v battery into a 7805 voltage regulator ro provide a verified 5v.

I have retraced the circuit, and even re-wired it several times already following your schematic.

Any other suggestions would be most appreciated.

Ashish Derhgawen said...

@Michael: Does sending any DTMF tone to circuit set the outputs to low, or are they always high no matter what you press?

robot said...

HELLO your project is excellant!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!VISIT __logic@febin_____search in google search===

Anonymous said...

Tie pin 10 to pin 15 instead (do not tie pin 10 to pin 18 which is V+).
This will allow the StD pin to enable the tri-state outputs so that the relay will ONLY be activated when a tone is present (otherwise the last tone will latch the relay on).

yanal said...

Hello Ashish, i have the same problem as Michael, the outputs Q1 - Q4 are always high no matter what i press, also is there a reason why you changed the Capacitor and the resistors values, i am using the CM8870PI and they suggested using .1uF, 100K ohms and 300K ohms for pins 17, 2, 3, and 16 respectively.

Anonymous said...

hi ashish , my name is jaya kumar , residing in bangalore....
studyin final year diploma , wanna do this project...but got sum doubts...plz help me....
wanna speak wid u....
my no is +91972312239 , send a text msg , wil cal u bak....

Anonymous said...

hi ashish , my name is jaya kumar , residing in bangalore....
studyin final year diploma , wanna do this project...but got sum doubts...plz help me....
wanna speak wid u....
my no is +919972312239 , send a text msg , wil cal u bak....

Ashish Derhgawen said...

Here's a solution Michael came up with if Q1 and Q4 are always high - Tie pin 15 to pin 10.

If I remember correctly, I connected a LED to pin 15 which always flashed when the circuit received a tone. I think that did the trick for me somehow.

fellow geek said...

That's awesome! Take a look at my project where I open my door using Bluetooth ;-) Throw away the key, baby!

mohit gupta said...

hey hi...plzz help man...
i want a circuit

i want 2 give input to a cellphone so that it may send a sms to particular number...plzz tell me hw 2 do man

mohit gupta said...

help me design circuit

mohit gupta said...

my gmail id is mohitrocks27@gmail.com

rahul said...

hi im rahul
im not getting how to connect earphone to ic....should i cut the wires and solder it to given pins of ic....plz help me..
ma id is raulnike01@gmail.com

mohan10 said...

you have done a grat job...r u running any other sites except this blog
http://thevintageacousticguitar.blogspot.com

jhon said...

Hai..u have done nice projects..i have bookmarked your site

Anonymous said...

ei..nice work...juz wana ask how did u connect the headset to the analog input of the DTMF receiver??bcoz the 2 headset that we got have 5 wires and we don't know which wire to connect....we are using MC145436AP dtmf Receiver.

Anonymous said...

ei..nice work...juz wana ask how did u connect the headset to the analog input of the DTMF receiver??bcoz the 2 headset that we got have 5 wires and we don't know which wire to connect....we are using MC145436AP dtmf Receiver..
tou can also email me at wency_dalumpines@yahoo.com

Unlock iPhone 3g said...

Nice video.

raji said...

hai your project is good,send clear details about DTMF becouse i am a ELECTRICAL student

Anonymous said...

how do you have the phone on the other side of the door answer automatically?

eizha said...

hi..
on june i'm going to work with my thesis...
actually it's related to your work...can you help me on it please?...it's all about cell phone controlled appliances....please send your reply to eizha_17@yahoo.com
thanks...God bless

Anonymous said...

Ashish's hello.'m from peru
I congratulate you on your projects, I know, when I call to cellular receptor, I do not activate LEDs or relays.
but the connection is working when I press the keys on the mobile, the LEDs are on for me every key tone
my email is
lucho67a@hotmail.com

luis said...

Ashish's hello.'m from peru
I congratulate you on your projects, I know, when I call to cellular receptor, I do not activate LEDs or relays.
but the connection is working when I press the keys on the mobile, the LEDs are on for me every key tone
my email is
lucho67a@hotmail.com

lucho67a@hotmail.com said...

Ashish's hello.'m from peru
I congratulate you on your projects, I know, when I call to cellular receptor, I do not activate LEDs or relays.
but the connection is working when I press the keys on the mobile, the LEDs are on for me every key tone
my email is
lucho67a@hotmail.com

Ashish's hello.'m from peru said...

Ashish's hello.'m from peru
I congratulate you on your projects, I know, when I call to cellular receptor, I do not activate LEDs or relays.
but the connection is working when I press the keys on the mobile, the LEDs are on for me every key tone
my email is
lucho67a@hotmail.com

de-electronica said...

Ashish's hello.'m from peru
I congratulate you on your projects, I know, when I call to cellular receptor, I do not activate LEDs or relays.
but the connection is working when I press the keys on the mobile, the LEDs are on for me every key tone
my email is
lucho67a@hotmail.com

Anonymous said...

Anonymous said...

Love this! want to build it but:

The circuit drawing does not look complete. There are parts I can see in the picture (like the 3 blue things and big capacitors). That are not on the drawing??? Can you post a complete circuit?"

The 3 blue things are the relays. There are some parts I haven't shown in the circuit diagram..for example, (1) I'm using a 7805 regulator chip for providing a steady supply of 5 V. (2) There's an LED connected to pin 15 of the 8870 tone decoder chip. (3) The big capacitor is a part of a bridge rectifier circuit which converts AC supply voltage to DC voltage. That's it. :)


but why r u using the bridge ciruit...where r u using AC...wats the value of the capacitor...???can the circuit work without the bridge circuit if i directly use DC.....also where does the relay get connected???plz reply ....really need 2know

Ashish Derhgawen said...

@anonymous: Yes, the circuit will work without the rectifier circuit if you supply DC. I included the rectifier circuit because I had to use AC.

The relays are connected across the 1N4001 diodes. (see the circuit diagram)

-Ashish

MultiFranc said...

Hi Ashish Raj, I am an italian student and follow your ideas on the net from a while: your job is great !
Sorry if I write you here but I have not your direct mail.
I need to develop an application through a ptz camera and one of your projects could help me.
Can you please contact me on franc@nectarine.it so I can explain the problem?
This would be very kind of you.

I'd be really really grateful

MultiFranc

codybanks said...

hey ashish i would like to know that whenever u press a number key den d two tones are produced having a higher and a lower freq. so if two keys are pressed simultaneously den what is d result??
also how do you decide on pressing which key d lock will open??
also do you dial a particular number and make a call in order to unlock d door or u just assign a number key and upon pressing that key it does opens up??
i want to study dis in detail any resources???

Anonymous said...

I know you've had a number of requests, but I was wondering if I could get a parts list and complete diagram. I'm a complete novice at this stuff and I could use a bit of hand-holding to help me through... My email is xequar AT lycos DOT com.

Thanks!

vysakh said...

hellow friend i am designing a teleremote system As a initial part of my project i have adopted your ckt but i have a problem here that is, as i make a call to my device and then when i press diffrent keys i am getting responce for only key no 3,6,9
and all rest are inactive what should i do now plz help as soon as possible
plz do male me at
yzak0@yahoo.com

Vijayanand said...

Hi Ashish,
Great project, I like it, I wanted to build this, Can you send me Part list and simple assembly diagramm on my mail
My e-mail-:vijayproxy@yahoo.com

Thanks and regards
vijay

Anonymous said...

hi,aloha! great design my friend, i'd like to build also that circuit..
if you don't mind, can you send parts list/components of your design.
is there any program to be used in some ic's?

pls. send it to my email
r_dimps@yahoo.com.ph

Anonymous said...

what are those parts in a nokia1100 cellphone did you cut in order to make it as your controller???
pls. my friend send me through email the details of your project...
pls. pls.

r_dimps@yahoo.com.ph

Anonymous said...

what are those parts in a nokia1100 cellphone did you cut in order to make it as your controller???
pls. my friend send me through email the details of your project...
pls. pls.

r_dimps@yahoo.com.ph

Sameer Khan said...

Hi Ashish...
I really appreciate ur work.. But I couldn't get the magic number thing and also a few more details..
Inspired by ur mobile controlled door lock.. I also want to implement it.. So can u kindly send me the details of the circuit and procedure used to build it.. Please.. I will be greatly thankful..

My email id is sameerkhansblog@gmail.com

the long tail said...

I don't think you will need and extra account with a cell phone company bc if you know about dtmf tones then you should know enough about PBX's or maybe you could string up Google Voice to work something with the lock. features compounded by features,

Anonymous said...

HEy....
I would like to know...

How I know what number is used...can i configure this?

After the answer of fone waht numbers i dial...how i know?

hugs

rahul said...

Hey man, I am using MT8870 and and Nokia 1650. Its works once with mobile and working fine with landline but not working with cellphone. What can be a probable reason.

shoureesh ganguly said...

Hi Ashish...
I really appreciate ur work..
Inspired by ur mobile controlled door lock.. I also want to implement it.. So can u kindly send me the details of the circuit and procedure used to build it.. Please.. I will be greatly thankful..plz help me out..

My email id is shoureesh@gmail.com

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Cellular Philippine Phone said...

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Anonymous said...

Hi Ashish...
I really appreciate ur work..
Great project, I like it, I wanted to build this, so can u kindly send me the details of the circuit, part list and procedure used to build it.. Please.. I will be greatly thankful..

my email is obradovic.milan87@gmail.com

fredk said...

Hi Ashish.
Your work is great.
I really like this project and would like to build it. Can can you kindly send me the details of the circuit, part list and procedure used to build it. Thanks.
haniff7@hotmail.com

ali daher said...
This comment has been removed by the author.
ali daher said...

hi i did your project,but in the circuit there is 4 relays each one for an device .i used a soleniod inorder to open the door.but how can i use the other 3 relays for other 3 devices that are about the door and the room.pleaze reply rapidly.my email is
alidaher1993@hotmail.com

rageshpnair said...

I have all the components required for this project. The PCB is ready and I have started soldering the project. However, I couldn't understand how to connect TIP and RING labels (shown at the input of the circuit) using the headset of the cell phone. Please help me. Do mail me if u can. am doin this project as my college mini project

ali daher said...

hi i did the project and maybe i can help you.pleaze specify for me the problem that is facing you maybe i can suggest you some solution inorder to help you.

rageshpnair said...

I couldn't understand how to connect TIP and RING labels (shown at the input of the circuit) using the headset of the cell phone.
Can i have ur Email Id.. so dat i can mail u...

rageshpnair said...

Actually me planning to do a CELL PHONE OPERATED LAND ROVER. Did u have ny experience in dat????

satish said...

hi.. we are doin GSM controlled door latch opener with security auto dial up?
kud u pls help us in the software part..the programming..

Avik said...

What if the battery of your cellphone dies ??
:p

barun said...

hi iam barun ,
i am do almost same project,
but, i face some problem with
est & st/gt pin .
when i connect a 0.1uF capacitor at st/gt pin using datasheet ckt , the project does not work ,but when i open the +Vcc part of capacitor & touch the lead of capacitor with my own hand then it work.
i try every other process to overcome it
,but i fail every time.so, plz..could you give me internal circuit diagram of
(not block dia.)ic cm8870pi ..
email id: barundasgupta0006@rediffmail.com.

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Anonymous said...

hi there, i need your help.i need a nokia 1100 with its keypad wire out into an external kepad, that is you wire each key maunally with wires and take those wires and wire the to another keypad.the keypad is made from micro push switches.i really need this to complete a project i,m working on.anytime i try to do it i burn the chipset.Thanks.ma contact info.

joseph Affran
p.o box 35,
legon accra
Ghana, West Africa

tel: +233244 118014
+233264 118014
email: automaticalarms@live.com.

pss. i admire your works. big thumbs up.

Anonymous said...

*********************************
dear ashish
Hi,i need this project to piece of my project immediately.
please send me schematic and code of this project.
Email:en_javidi@yahoo.com
Best regard!!!!!!!!!!!!!!!!!!!!!!
**********************************

- - - † NachiĆ© † - - - said...

hi,
I am building a similar system at my home. Although most of the work is done, I am unable to find a decent solenoid(the kind used here) around in India. Can you direct me to where I can purchase one(I am from Pune).

On the post - great work here. Amazing thought of doing it via a cellphone :) Cheers!!

Anonymous said...

i totally agree with your "laziness ..." quote.. :) good work..

diva said...

wow nice, i hope i can use it in my home :D

phone lookup said...

Good stuff - next you need to do a garage door opener.

ravi said...
This comment has been removed by the author.
ravi said...
This comment has been removed by the author.
ravi said...

hi, myself RAVI. we r doing this project in our college.
I would like to ask u about the connection of the Headphones to the circuit. Bcoz wen we had cut the Headset there were 9 different wires internally. so we got confused which one to put in the ckt.
We r using a nokia 6233 phone.. Is it applicable or not plssssssss can u tell us.
can u tell me which crystal oscillator hav u used is it the one in the diagram only or another one.
gmail:- ravi.ittagoni@gamil.com

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Anonymous said...

can you tell what are the materials you have used on that invention?

Anonymous said...

how you send the data from the circuit to the door to open it?

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francis said...

Nice post!

Are the signals from an ordinary telephone will also work? Is it possible to dial from my office to my home then have a call receiver then I will just input the command to turn-off/on an appliacnce, maybe my computer.?

Anonymous said...

nice post!

send me the complete circuit diagram or the step by step instruction to do this nice project... plsss...
i'd like to build one...
my e-mail joms0102@yahoo.com

muhammadrazzaq said...

Currently using an LG Neon that is showing its age (randomly turning itself off). I'd love to try something else!

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nadeera said...

i think its a interesting project so im thinking to this for 3G phone as my final year project. im from Srilanka can you please send me your complete project with complete circuits diagram. thanks.

nadeera said...

also i need your solenoid door lock part also . does it can open with old keys also. can you please send me the mechanical part of your door latch!! please

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Anonymous said...

i love this project and i wanted to build it can give me the details.. thanks a lot
@ cjbugoy08@gmail.com

burramukkuprasanthreddy said...

the dtmf decoder circuit shown is not working when we connected, we need help asap pleasee!

burramukkuprasanthreddy said...

hii , we are working on similar project, we are not getting any output from the dtmf decoder, can u pleaase help us asap, we have a competition on this within 2 days , so please can u help us

Unknown said...

i have been doing it as my mini project please give me ceratain details about the circuit .awaiting for ur reply.
msainath4@gmail.com

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nidhi said...

can you please send the complete circuit diagram and the connections
with the cell phone n can u please send us software part of this project in d email id given as soon as possible .
email id: lnidhi1500@gmail.com

fery setiawan said...

hello my name the ferry
I want to deepen the program that you create ...
if I may ask for a complete matreinya ... feri_setiawan429@yahoo.com
thank you

Imran Khan said...

lol i tried but its not working .. my screen black :(... help me out plz..
thanks in advance

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GEORGE AMO QUANSAH said...

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Manuel Marquez said...

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kishan said...

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