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Aaru
03-21-2010, 09:41 PM
Hi I'm constructing a bot using a DTMF decoder IC... I got the circuit from EFY, given for testing DTMF tones in landlines. I've included a combinational circuit to control the bot. This is my prob-how to channel the DTMF from my mobile to the ckt??If I'm using a headset, how do i separate the two silk wires n giv them to the ckt? pls explain in a detailed manner, with photos if possible..

akshay66
03-22-2010, 11:44 AM
When you strip the wire from head set you'll get 2 wire known as tip & ring.Just connect them to your circuit.Now the question arises how to differentiate b/w them its a difficult process because different headsets have different colors of wire I mean different companies manufacture different.You'll have to use hit & trial method.it will be a short process as there are two wires only.i'm not sure but nokia has red colored wire as ring & blue as tip.

Ulhas
03-22-2010, 12:53 PM
The circuit you are refering from EFY if i am guessing right is for testing MT8870 dtmf decoder ic and circuit is designed for land line.
However you can simply use capacitor and one resistance in series to input DTMF tone to your circuit from head set directly.

Note use seperate stereo male pin connector solder three wires to it, tip is alaways common, try one-one from rest two.
Although attached snap shows MT8870 it is perfectly worked and tested with CMD8870.

akshay66
03-22-2010, 02:51 PM
Please tell us the date of issue of EFY??Because i'm referring to the circuit on JULY 2008 it is a mobile controlled one.

Aaru
03-23-2010, 09:38 PM
Sorry but i dunno the date of the issue, got it from net...I'm using a nokia 2626 headset.When i stripped the wire below the mike attachments, i found 2 silk wires within each separate strand...how shd i give them to the ckt?I'm also simultaneously experimenting another ckt from instructables.com...using cm8870:confused:I've attached both circuits with this post...

Ulhas
03-23-2010, 10:41 PM
Exactly the same one about which i wrote earlier. You don't need balanced circuit at input tone side. Refer and construct mine one on breathboard and go for it
it is too simple and tested by me

the second for print circuit is made unnecessarily complex . AVR has internal pull ups no need to connect it externally, the circuit is poorly designed it don't make use of stD pin etc.
Anyway you have lot of scope to refine it. Do it and have a real esence of designing it yourself

akshay66
03-24-2010, 06:07 PM
ulhas is correct the second circuit is from july 2008 issue the one i was talking from.The circuit is poorly designed.Try find a better circuit.This one is not reliable.

Mohammed Mustafa
04-07-2010, 12:42 AM
I use the same circuit as Ulhas & I'm sure it's correct ,my only problem is the input using the headset , so can you explain it more to me , I need this help as fast as possible please.

Ulhas
04-07-2010, 01:28 PM
Here it is , i have explained it earlier also

Note to use seperate stereo male pin connector solder three wires to it, tip is alaways common, try one-one from rest two.
Although attached snap shows MT8870 it is perfectly worked and tested with CMD8870.

Mohammed Mustafa
04-09-2010, 02:10 AM
Thanks its working very well!!!

Ulhas
04-09-2010, 08:46 AM
Many mobiles don't generate DTMF tone as default like my Nokia N95.
You have to go to setting and try playing with keypress tone setting.
One out of them will definately work

To check whether mobile geneartes dtmf or not, You place a call from landline to your mobile and pick up at mobile and press the keypad numbers ,
and then check does it works or not ?

As i said i have tested it and found 100% working with my Nokia N95, a Very old nokia phone, and with landline too

sudarshan
05-23-2010, 11:30 AM
does ring refer to the ground
and
does tip refer to left or right channel

shyam.sunder91
05-25-2010, 09:00 AM
hey dudes will it have any feed back i mean if we press the key that is already in function will the recever give any feed back to us is there any system like thant reply me soon

Ulhas
05-25-2010, 07:47 PM
Not exactly until you connect mobile mic connection to your uC with audio transformer
OR
design single transistorised amplifier with BUZZER, connect it to Uc IO pin. Place buzzer near mobile MIC , get the feedback as a number of beeps you get at caller end

simar.i3r
05-30-2010, 03:57 PM
hello i'm a new user simar ... this worked for me also ...
thanks

sudarshan
05-30-2010, 04:57 PM
what does the pin tip and ring reffer to in the headset?

does ring refer to the ground and tip refer to left or right channel ?
please help me out

Ulhas
05-30-2010, 09:30 PM
Tip is the start of stereo pin which can be either Left or Right channel.
Extreme last portion sleeve of pin ie which is nearer to closing plastic cover is always GND
See attached image for terminology

sudarshan
05-30-2010, 10:37 PM
thanks a lot

shyam.sunder91
06-17-2010, 01:52 PM
When you strip the wire from head set you'll get 2 wire known as tip & ring.Just connect them to your circuit.Now the question arises how to differentiate b/w them its a difficult process because different headsets have different colors of wire I mean different companies manufacture different.You'll have to use hit & trial method.it will be a short process as there are two wires only.i'm not sure but nokia has red colored wire as ring & blue as tip.

actually my mobile jack has the things same as u said
but the jack has two wires each with another pair some thig like show in figure
one with red and a copeer coloured wire
and other with green and copper couloured
now how to connecthttp://www.webewitch.com/CIMG6501.jpg

this is not the actual photo but look exactly the same can u say me which is the tip and rip seeing at back side

Ulhas
06-17-2010, 10:01 PM
actually my mobile jack has the things same as u said
but the jack has two wires each with another pair some thig like show in figure
one with red and a copeer coloured wire
and other with green and copper couloured
now how to connecthttp://www.webewitch.com/CIMG6501.jpg

this is not the actual photo but look exactly the same can u say me which is the tip and rip seeing at back side

Are you kidding ? or employeeing us without salary !!!!!!!!!
why don't you go which was explained ?
Or do you have made the connector you have shown with your attached pic
Use simple connector and finish your work

jeetbuz
06-26-2010, 11:59 PM
hi
i am making a ivrs project using cmd 8870 decoder ic, in single ended input mode.
i connected the pins as shown in the datasheet, but there is no output(std pin is high).
i have grounded 5,6 and oe is high too.
connected the silk wire from the headphones, 1 to input and other ground.
i am using a nokia phone and calling from a landline

plzz tell me wats wrong

wat shld be the voltage at input pin
it shows 2.5 and 0 when i connect the silk wires.

praghu_cool
06-28-2010, 01:23 PM
Hi,
I am the author of the ckt that is published in efy july 2008. Actually I have used HT 9170B. the ckt works perfectly with this IC. It took just one day for me to do this. But EFY has modified the ckt as they did not get HT9170B.
More details on this project are present in my blog www.raghu.co.nr