8051 Microcontroller Projects AVR PIC Projects Tutorials Ebooks Libraries codes : Forum / topic http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb Creative Commons LicenseThis work is licensed under a Creative Commons Attribution-Noncommercial 2.5 India License.Rickey's World Disclaimer Ajay Bhargav - contact@nospam.com contact@nospam.com Mon, 01 Dec 2008 12:26:25 -0800 Mon, 01 Dec 2008 12:26:25 -0800 http://backend.userland.com/rss e107 (http://e107.org) 60 Search Search 8051 Microcontroller Projects AVR PIC Projects Tutorials Ebooks Libraries codes query http://www.8051projects.net/search.php dtmf project [help] http://www.8051projects.net/forum-t4286.html
i recently finished my first project (car based on 8052 uC with wired remote).

now i want to make remote wireless and i am thinking about dtmf (not rf). i read about it on net (googled it and read many tuts), but don't get anything !!! i dont know about circuits much !!! so please help me !!!
i also found a good site but not get much !!!
http://www.freewebs.com/maheshwankhede/dtmfdecoder.html

i donot konw how to interface phone with these chips( CM8870 and KT3170) and the circuit diagram is very diffcult to understand !!! i dont know what to do ???]]> Thu, 27 Dec 2007 13:21:29 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html i hav to put all the resistors, capacitors and transistor or they are in build ???

my plane is to call the other phone on car through my phone !!! and then operate the car with my phone !!]]> rahuljin<friend.rahul@nospam.com> Fri, 28 Dec 2007 00:07:38 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html the circuit given in that website is fairly simple. i recommend you to read datasheet of CM8870 will make you clear about the working of IC and interface.

DTMF also need a wired interface.. are you going to use telephone line?]]> Ajay<contact@nospam.com> Thu, 27 Dec 2007 23:35:57 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html yes you need all resistor caps and crystals..
also you need to make circuit that detect ring and pick the call.. after that directly couple the speaker with CM8870.]]> Ajay<contact@nospam.com> Fri, 28 Dec 2007 01:56:52 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html rahuljin<friend.rahul@nospam.com> Fri, 28 Dec 2007 05:52:56 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html be smart ]]> Ajay<contact@nospam.com> Fri, 28 Dec 2007 06:34:21 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html xx1mar<xx1mar@nospam.com> Fri, 28 Dec 2007 15:01:36 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html for DTMF conversion/reception.]]> Ajay<contact@nospam.com> Fri, 28 Dec 2007 23:43:04 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html relay dpot in that circuit and what is the use of that circuit ,and also how can i connect the whole circuit with the headset of the phone as u have mentioned above
do i have to cut the wire of headset and then join it to circuit]]> rahuljin<friend.rahul@nospam.com> Thu, 17 Jan 2008 05:32:17 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html rahuljin<friend.rahul@nospam.com> Thu, 31 Jan 2008 07:21:11 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html Ajay<contact@nospam.com> Thu, 31 Jan 2008 10:48:24 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html
i dont get the use of this DPDT reply !!!

so what is the need of ring detector, i mean nokia has a option to accept the call automatically !!

also i want to ask that the wires are attached to relay or can i attach them to dtmf decoder ???]]> rahuljin<friend.rahul@nospam.com> Sat, 02 Feb 2008 01:03:52 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html Ajay<contact@nospam.com> Sat, 02 Feb 2008 01:28:50 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html rahuljin<friend.rahul@nospam.com> Sat, 02 Feb 2008 08:27:44 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html Ajay<contact@nospam.com> Sat, 02 Feb 2008 10:12:22 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html rahuljin<friend.rahul@nospam.com> Sat, 02 Feb 2008 20:45:14 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html
One thing you can do is.. use auto answer and ask user to press * to start with the further work.. you can also couple microphone with controller to feed voice response..]]> Ajay<contact@nospam.com> Sun, 03 Feb 2008 20:25:50 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html i sent the dtmf tone to other mobile then it is taken by cm8870 and output of cm8870 is obtained. then this output is given to microcontroller, and an other output is obtained at other port of microcontroller.
now my problem is that the port does not refresh after the output is obtained. i get same output untill i press another key !!!
i tried to give setb to std (in cm8870) through microcontroller !!
i also tried to refresh the port but no use !!!

]]> rahuljin<friend.rahul@nospam.com> Sat, 01 Mar 2008 11:27:38 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html Something like this pseudocode

CODE:
Sub St_dtmf
         if Stb = 1 then
            mov     a,P0               ;get data from MT8870
            anl     a,#15               ;4 bit  low nibble
            lcall   conv_tone         ;convert to ascii
            Txx  =  Acc
            DtmfString = DtmfString + chr(Txx)         ;save
            do
            loop until Stb = 0          ;wait end dtmf
         endif
End sub
;
Conv_tone:
        inc     a              
        movc    a,@a+pc        ;get from table
        ret
        db      H44,H31,H32,H33          ;D123
        db      H34,H35,H36,H37          ;4567
        db      H38,H39,H30,H2A          ;890*
        db      H23,H41,H42,H43          ;#ABC
 


Regards
Gianni]]> GioppY<gia.ma.fra@nospam.com> Sun, 02 Mar 2008 04:39:55 -0800 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html
the input lines to DTMF is speaker lines or what?
]]> amer<engameer_2010@nospam.com> Mon, 09 Jun 2008 00:29:48 -0700 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html
the speaker(which is kept near the ear) wire is connected to dtmf decoder.]]> rahuljin<friend.rahul@nospam.com> Mon, 09 Jun 2008 01:07:39 -0700 http://www.8051projects.net/forum-t4286.html Re: dtmf project [help] http://www.8051projects.net/forum-t4286.html http://onlinetps.com/raghu/]]> ۞ TPS ۞<tpsbpl@nospam.com> Sun, 29 Jun 2008 05:30:01 -0700 http://www.8051projects.net/forum-t4286.html