Hi,
check out the CM8870. It's a full DTMF decoder with AF input via electret microphone.
Adjust AF amplification with P1. Pin15 (STD=Delayed Steering Output) goes high when a valid signal (SIGVALID) has been received, and serves as signal to read Q1 to Q4 (A0 to A3).
Boncuk
DTMF reciver for mobile
-
24th July 2010 04:40 AM #1Sohaib Siddique
DTMF reciver for mobile
its my 2nd thread i hope my problem is solve
i want dtmf reciver for nokia mobile
dtmf reciver easily interfarnce with mobile plz give me dtmf reciver circuit.
regard
-
24th July 2010 07:39 AM #2Boncuk
0
-
24th July 2010 06:38 PM Thread Starter #3Sohaib Siddique
thx i will try kindly breef me wit detail plz
0
-
24th July 2010 06:43 PM Thread Starter #4Sohaib Siddique
u mean pin 15 is high when output
and rn1a is grnd and other also grnd? (RN1B, RN1C and RN1D)0
-
25th July 2010 09:36 AM #5Boncuk
Pin15 goes high if a valid DTMF-tone combination has been received. RN1 is a four resistor array with a common ground pin meant as pull down resistor for the outputs Q1 through Q4 (A0 .. A3). Q1 .. Q4 are binary coded outputs with Q1 being the LSB.
Please download the data sheet and study it carefully. It also contains a look up table for binary outputs according to frequencies generated by DTMF devices.
Other than binary values the CM8870 decodes a 'Zero' being "0000", instead of "1010", provided by a binary coded switch.
So if you want to create a DTMF-lock don't use 'Zero'.
Boncuk0
-
25th July 2010 05:09 PM Thread Starter #6Sohaib Siddique
Thx very much
0
-
29th April 2012 08:57 AM #7gagandeep
DTMF help
EDITED CKT..pnghi ,
i am interfacing dtmf 8870 with p89v51rd2, Need help with mt8870DE in myanmar-edited-ckt..png circuit attached
i am not getting desired led outputs by connecting nokia phone
please help
RD pin of 8051 to be connected????0Last edited by gagandeep; 29th April 2012 at 08:58 AM. Reason: circuit attached
-
29th April 2012 02:27 PM #8audioguru
I am in the West. Most of us Western people played with DTMF about 32 years ago. Unfortunately the internet was not used then so the articles about DTMF are not on the web today. Also cell phones (mobile phones?) were not used then.
Many printed magazines from the West about 32 years ago talked about DTMF.0Uncle $crooge
-
29th April 2012 03:27 PM #9Reloadron
How exactly are you getting the tones to the decoder. The drawing really does not show that part. What exactly happens with the LEDs?
Ron0Please do not PM me with forum related questions. Let's keep things in the open forum. Thank you.
-
30th April 2012 04:12 AM #10gagandeep
Originally Posted by Reloadron
LEDs connected on o/p of dtmf
On reset - 0110
On pressing 1- 1000
on pressing keys leds glow for some time and again reset (0110)
even 8051 not responding
please check code
org 00h
mov p1, #0ffh; // Port1 as input port
mov p2,#00h ; // Port2 as output port
start:
mov a, p1;
cjne a,#0ffh, for1;
jmp start;
for1:
mov a, p1;
cjne a,#01h, for2 ;
mov p2,#01h;
jmp for1;
for2:
mov a, p1;
cjne a,#02h, for1;
mov p2,#02h;
jmp for2;
end
Thanks alot0
| Tags |
| Similar Threads | ||||
| Thread | Starter | Forum | Replies | Last Post |
| DTMF Reciver Problem | ghauri | Electronic Projects Design/Ideas/Reviews | 4 | 23rd May 2010, 08:26 PM |
| Please help me with an sony reciver | little_alien | Electronic Projects Design/Ideas/Reviews | 2 | 30th October 2008, 06:17 PM |
| Infrared Reciver | CommanderKeen | Electronic Projects Design/Ideas/Reviews | 17 | 21st April 2006, 09:06 PM |
| reciver | yasiny | Microcontrollers | 2 | 14th April 2006, 01:03 PM |
| dtmf reciver n transmitter | abdu | General Electronics Chat | 0 | 5th January 2005, 06:07 PM |