applications of dtmf

[simrantogether]

I searched many threads.. but i didnt got the applications of Dtmf..

I have the tutorial and interfacing circuit diagram..

but i wanted to know its various applications..

Please post your ideas and knowledge..

Regards,

Simran..

 

[Nigel Goodwin]

I searched many threads.. but i didnt got the applications of Dtmf..

I have the tutorial and interfacing circuit diagram..

but i wanted to know its various applications..

Please post your ideas and knowledge..

It's really very old technology (40 years?), it's still used for what it was designed (dialing phone numbers) - pretty well anything else was replaced by digital methods decades ago.

 

[Gayan Soyza]

Hi Simran DTMF (8870) testers are all over the web.

Try searching MT8870 DTMF tester.In india Also I saw many projects done with this IC interfacing to a micro controller.Its very easy.

 

[simrantogether]

it's good..

Thanks ...

it's good if we can dial the phone numbers.. using microcontrollers...

1. can it be used for generating number of phone lines... from one line..

2. can it be used for controlling from Long diatance like 100 kms through phone..

3. Dual tone means.. ? and multi frequency means.. ?

actually i was thinking for applications point of view and hobbyists can help most in this...

Regards,

Simran..

 

[simrantogether]

Hi...

Hi Simran DTMF (8870) testers are all over the web.

Try searching MT8870 DTMF tester. Its very easy.

Is DTMF tester same as dtmf applications like decoder..

here ' tester ' means..

Actually the tutorial i'm following is:

https://www.freewebs.com/maheshwankhede/dtmfdecoder.html

Regards,

Simran

 

[Gayan Soyza]

MT 8870 is a DTMF tone decoder IC.Yes its a similar project.

When it hears a valid tone pair it starts counting binary & showing by the 4 bits.By this 4 bits its giving input to the micro & detecting what inputs have come.So it can determine which output to be turn on or off.

 

[simrantogether]

that means..

that means :

it counts from ' 0000 b ' till ' 1111 b' in binary form in an infinite loop ...

and suppose when we pressed any key suppose '5' then it after detecting '5' gives it to microcontroller...

Am i right?

Regards,

Simran..

 

[Gayan Soyza]

Yes when you press number 5 it will show b’0101’ from the 8870 outputs. If you connect 4 leds to the output of 8870 you will see the first & the third leds will lights up when you press five.

So we are writing a program inside a microcontroller if this value b’0101’ has come to the micro then turn on the fifth relay.

If you press number 1 then it will display b’0001’ so you tell micro if bit 0 has set then turn on relay one etc……

 

[simrantogether]

Hey Gayan..

Hey Gayan.. Its wonderful...

One very important thing i would like to ask from you..

Can we use DTMF 8870 for making our " keypad " because usually.. what we see is that the algorithm of general keypad is tough..

I think you might have followed the book called Mazidi and Mazidi.. that keypad algorithm is tough..

Regards,

Simran..

 

[Gayan Soyza]

Can we use DTMF 8870 for making our " keypad " because usually.. what we see is that the algorithm of general keypad is tough.

You can but incase if the steering pin if wont go high it wont make any outputs from 8870.So better make a keypad without taking DTMF.

For me DTMF is better to control device in the vicinity.

 

[simrantogether]

thanks..

Thanks Gayan.. for frequent answers...

Regards,

Simran...

 

[Nigel Goodwin]

Can we use DTMF 8870 for making our " keypad " because usually.. what we see is that the algorithm of general keypad is tough..

Scanning a matrix keypad is really pretty easy, easier (and a LOT cheaper) than using DTMF - which would really be a silly way to do it.

 

[simrantogether]

Actually the keypad ..

Actually the keypad i am using ..

Sir, i find it a bit tough...

just for detecting one key out of 16 keys.. it takes a very big program in ' c language '.

but then also i'll try...


Regards,

Simran..

 

[Nigel Goodwin]

Can't help you specifically on 8051, but my tutorials show how to do it in PIC assembler - exactly the same principles apply though, no matter what the processor, or language.

 

[simrantogether]

Yes sir..

Sir yes..

I'll definitely try ..

Actually, i needed some help ...

if possible .. please answer the following questions:

1. can DTMF be used for generating number of phone lines... from one line..

2. can DTMF it be used for controlling of stepper motor from Long diatance like 100 kms through phone..

3. Please tell the name of the example project that can be made on interfacing DTMF with controller..

Regards,

Simran..

 

[Nigel Goodwin]

Sir yes..

I'll definitely try ..

Actually, i needed some help ...

if possible .. please answer the following questions:

1. can DTMF be used for generating number of phone lines... from one line..

No, it's just two audio notes, harmonically unrelated, played at the same time.

2. can DTMF it be used for controlling of stepper motor from Long diatance like 100 kms through phone.

For really slow, very restricted, control yes it could.

3. Please tell the name of the example project that can be made on interfacing DTMF with controller..

Display the number dialled on your phone?.

 

[Nigel Goodwin]

Sir yes..

I'll definitely try ..

Actually, i needed some help ...

if possible .. please answer the following questions:

1. can DTMF be used for generating number of phone lines... from one line..

No, it's just two audio notes, harmonically unrelated, played at the same time.

2. can DTMF it be used for controlling of stepper motor from Long diatance like 100 kms through phone.

For really slow, very restricted, control yes it could.

3. Please tell the name of the example project that can be made on interfacing DTMF with controller..

Display the number dialled on your phone?.

 

[simrantogether]

I got it...

I feel I got it, Thank you Sir..

No, it's just two audio notes, harmonically unrelated, played at the same time.

It means that just we can do basic operations like detecting the key that is pressed ond other simple operations like detecting dial tone etc.

For really slow, very restricted, control yes it could.

yes.. it means that .. it is possible .. (atleast some projects i can meke..)

Display the number dialled on your phone?.

Similarly that we have it on our PCO ( public call office ) booth...

Regards,

Simran...

 

[Nigel Goodwin]

Sir yes..

I'll definitely try ..

Actually, i needed some help ...

if possible .. please answer the following questions:

1. can DTMF be used for generating number of phone lines... from one line..

No, it's just two audio notes, harmonically unrelated, played at the same time.

2. can DTMF it be used for controlling of stepper motor from Long diatance like 100 kms through phone.

For really slow, very restricted, control yes it could.

3. Please tell the name of the example project that can be made on interfacing DTMF with controller..

Display the number dialled on your phone?.