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Home Device controlling dialing a call from mobile

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contactarman1

New Member
I am currently studying in engineering. We have to a academic project in final year.

We have chosen "Home Device controlling dialing a call from mobile"
We have to use a 89c51 or 89s51 microcontroller

We have just started last week, so I thought I should gather some information from internet resources... and thats why I am here...

If anyone have circuit diagram, pcb layout, microcontroller program, then please post it here....

waiting for your reply....
 

contactarman1

New Member
sorry for my english :)
user is going to dial a call to the mobile which is connected to project
and then microcontroller will act upon those instructions
and then microcontroller will turn on/off the respective devices...
 

AtomSoft

Well-Known Member
SOUNDS LIKE A BOMB TO ME HEH sorry for caps... i wouldnt help here mainly because im tired of people who actually get to attend school and have the opportunity to learn this stuff and then .... ask for help online on the entire project???

whats up with that? if you went to school you should have a idea of what to do.... do about 60% of your project and then write back here.
 

rushi53

Member
user is going to dial a call to the mobile which is connected to project
and then microcontroller will act upon those instructions
and then microcontroller will turn on/off the respective devices...

This is related to DTMF,
connect mobile headphone output to DTMF decoder
User MT8870 dtmf decoder IC
go through the datasheet,
you will find that there are total 4 output pins,
connect those output pins to microcontroller
I would suggest 89s51, if you are a beginner.
Now run a program inside microcontroller to read the input ports and then take respective action.
Use relays at the output
It would be like this:
Mobile ==> DTMF Decoder ==> Microcontroller ==> Relays ==> Devices
 

sahu

Member
This is related to DTMF,
connect mobile headphone output to DTMF decoder
User MT8870 dtmf decoder IC
go through the datasheet,
you will find that there are total 4 output pins,
connect those output pins to microcontroller
I would suggest 89s51, if you are a beginner.
Now run a program inside microcontroller to read the input ports and then take respective action.
Use relays at the output
It would be like this:
Mobile ==> DTMF Decoder ==> Microcontroller ==> Relays ==> Devices

dear friend how to canact ? with ..........Mobile ==> DTMF Decoder
 
Last edited:

sahu

Member
I am currently studying in engineering. We have to a academic project in final year.

We have chosen "Home Device controlling dialing a call from mobile"
We have to use a 89c51 or 89s51 microcontroller

We have just started last week, so I thought I should gather some information from internet resources... and thats why I am here...

If anyone have circuit diagram, pcb layout, microcontroller program, then please post it here....

waiting for your reply....

if ur req. pic 16f84a . may be i can help u.
 

sahu

Member
Connect with the wire of headphone.
I mean connect headphone to the mobile,
cut the wires going towards the earphones,
connect these wires to the input of DTMF Decoder
pl clr. my daout
1...i call mobile,
2...#123411* [this DTMF signal , how can come from mobile to the headphone ? means,what the action of caller mobile or landline? ]
 

rajbex

Member
contactarman1,
I hope you must have a landline phone to do this project. I have designed this project a long back, but I lost everything. But can tell you, what did I used. I used AT89C51 as a main controller, and MT8870 IC to convert the DTMF signals in to BCD. I used a 555 timer and a 741 Opamp for ring detection circuit. The ring signal voltage level is differs sometime in different countries. Once you detect the ring, you can program after how many rings your microcontroller is going to take the call. You can create a Hook OFF situation by turning a relay switch ON which connects a 120 Ohm resistance parallel to the telephone line. This is exactly what happens when you pick your phone.
After that, you can program your controller to ask for the password first from the remote user. The keypad entries from the remote users can be read through MT8870 chip, which has a status pin that goes high when it recieves a valid DTMF tone.
I would say you will find bunch of literature in this topic on internet. I did it in year 2000, and I did have found some at that time.

Good Luck.
- Raj
Experiments with PIC16F628A
 
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