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YS
Nobel Prize Winner
USA
1132 Posts |
 Posted - Jun 13 2003 : 9:53:14 PM
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Khalifa,
you definitely must separate grounds. Otherwise your counter will be connected to phone line, and it is to be avoided. Check your power connections. detector circuit gets the power from the phone line, while counter should be powered with 5V DC. Optoisolator serves just for that - to completely separate grounds and power.
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DELETED (Inactive)
27 Posts |
Posted - Jun 14 2003 : 04:38:31 AM
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HI There
I have separated the grounds, the display dancing is due to .5 volts that comes from the emitter during the ringing to the input of my counter.
Although, I have connected the emitter to the ground via 100K ohm and I am taking the input from the emitter to the input of my counter via 100km as well.
When I disconnect the input from the counter, the display is steady during the ringing. So I don’t think it is due to improper grounding. It looks like a leakage.
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YS
Nobel Prize Winner
USA
1132 Posts |
Posted - Jun 14 2003 : 4:52:31 PM
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no, there is absolutely nothing wrong with the circuit. You just forgot to mention it was during the ring. Ring is 20HZ 100V AC signal and naturally it will create series of pulses. You need to use a filter (capacitor) between 4N35 emitter and ground. Find a value when ring is not counted but real on-off hook condition is. Start with 1uF. The bad thing is that if the cap is too big than volotage will change very slowly and counter may not count reliably. If so, you will need to add a Schmitt trigger (use two inverters of 7414 in series) between the 4N35 and counter.
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DELETED (Inactive)
27 Posts |
Posted - Jun 16 2003 : 6:13:16 PM
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Hi YS
Hope you are doing fine today.
I have put the cap and the inverters as well as you have suggested. I can see improvement. But, something strange had happened and I cannot find out the reason. My counter stopped counting. I have changed every piece of my component. I also checked all the connection. I have notice , it will only count when I attached the positive lead of my digital meter on pin one of the 7414 and the negative led to ground. !!!!! and there is always 1.45v on pin 1 without having anything connected to it. I tried changing the chip but still the same.
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YS
Nobel Prize Winner
USA
1132 Posts |
Posted - Jun 17 2003 : 12:19:25 AM
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Khalifa,
do you have a resistor between pin 1 and ground? Sounds like you missed it. your meter acts like a resistor, that's why it helps.
you should connect emitter of 4N35 to:
capacitor
resistor 100K
pin1 of 74hc14 (or other CMOS; hope you did not use TTL. If so, reduce resistor to 10K)
Other side of capacitor and resistor should go to ground.
On unused elements of 7414, tie inputs to ground or +5V - either way.
Shunt logic ICs with capacitors - means each logic IC should have a 0.1uF or about that ceramic capacitor between power pin (14 or16) and ground, and this caps should have short leads. Good luck, YS
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DELETED (Inactive)
27 Posts |
Posted - Jun 19 2003 : 7:12:38 PM
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Hi YS
So far the circuit is working fine. I am still testing it. In the same time I am thinking of connecting it to a serial port and have small program to read the input from this port and log the calls. It is only an idea at this time. Whether it can be done or not, I don’t know. The big challenge is how the port will identify the calls from each line.? I think it is easy if you read the input from one line. But when you have many lines!!! I think it will be hard.
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YS
Nobel Prize Winner
USA
1132 Posts |
Posted - Jun 19 2003 : 11:24:42 PM
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So, you got it working - congratulations!
if yu want to connect it to PC, think of using printer port. On most newer computers it is bidirectional, and even on oldest PC you still have 5 input lines, TTL or CMOS (5V) level. You do not need the counter; software can do that. Just connect an output of 4N35 to appropriate wire. Connect grounds, of course. Also you do not need 5V to power right side of 4N35 if you manage to connect it (+5V wire) to one of the output pins of printer port and set it to high level, which will be between 4 and 5V. You can keep a filtering capacitor to prevent ring coming, but I would rather make it in software - and at the same time you can even distinguish rings (they come at 20Hz frequency). There is some information on this website concerning printer port use for automation, but I think you do not need any hardware beyond described above. Just make sure you use optoisolators between PC and phone line.
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DELETED (Inactive)
27 Posts |
Posted - Jun 20 2003 : 09:01:31 AM
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]With out your help I would not even have my LED to flash. Thank you SIR.
Thank you again for the information, I think I will go with the counter at this time and I will think of the PC port at later stage. Any idea where can I order printed circuit board kits as it is very hard here to find the solution for the boards here. I know they are available in the state.
Thanks
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YS
Nobel Prize Winner
USA
1132 Posts |
Posted - Jul 10 2003 : 11:27:05 PM
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You are very welcome, Khalifa.
PCB kits may be available at www.mouser.com, www.digikey.com, www. jameco.com and so on.
Good luck!
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DELETED (Inactive)
27 Posts |
Posted - Nov 01 2003 : 07:57:44 AM
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YS
it is a long time my old friend...how are u.
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DELETED (Inactive)
27 Posts |
Posted - Nov 01 2003 : 08:01:11 AM
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I have finished my project..i have done it for 8 lines.it working fine and it is in production. have asked me to do the same for more 8 lines. I would realy thank u again for your help. any i need your home address if your dont mind.
thanks
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YS
Nobel Prize Winner
USA
1132 Posts |
Posted - Nov 01 2003 : 10:30:15 PM
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Hi Khalifa,
I am happy to hear you have done it. You put so much efforts and dedication in your project, we all can learn from it.
Good luck with your job!
My address is yulis14@hotmail.com.
Best regards, YS
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DELETED (Inactive)
27 Posts |
Posted - Jul 03 2004 : 08:55:38 AM
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quote:
Hi Khalifa,
I am happy to hear you have done it. You put so much efforts and dedication in your project, we all can learn from it.
Good luck with your job!
My address is yulis14@hotmail.com.
Best regards, YS
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YS
Nobel Prize Winner
USA
1132 Posts |
Posted - Jul 03 2004 : 9:57:08 PM
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Hi Khalifa,
I got your emails and replied at once, several times. But it never reached you for some reason, it was always returned to my hotmail address by your web server. Maybe it is set to block hotmail? I am still there, though.
Best regards,
YS
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DELETED (Inactive)
27 Posts |
Posted - Jul 09 2004 : 06:49:38 AM
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HI YS
Are still in this address ?
thanks
khalifa
Yuli Starodubtsev
320 Knollwood Drive
Hampstead, NC 28443 USA
quote:
Hi Khalifa,
I got your emails and replied at once, several times. But it never reached you for some reason, it was always returned to my hotmail address by your web server. Maybe it is set to block hotmail? I am still there, though.
Best regards,
YS
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Topic |
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cut phone line detector
