comment [14]
- From trax on 22-08-2010 at 11:00:51
Check your e-mail...
IP: n/a
/Projects/Phone recorder
How many times have you wished that you recorder your recent telephone conversation? I have, many many times. So I finally decided to make this happen by using PC and a piece of hardware (powered from USB) to record audio from phone line to MP3 format. I wanted this thing to work automatically, to start recording when any of phones in house is picked-up (line occupied) and stop recording when all phones are hung-up (line free).
UPDATE: The .RAR file is now updated. So if you have seen the "Output mp3 directory is not valid..." information upon application start, just edit the "opcije.ini" file and adjust the mp3 output directory.
[I'm on Hack-A-Day and also on HackedGadgets :-)]
You can download the project files (schematics, source code, windows app) by clicking on the red download button at the end of this article.
How does it work?
The hardware-part consists of:
- audio pickup circuit
- phone line status monitor
- microcontroller to send the phone-line state to PC using USB (serial<->usb)
The software:
- receiving the phone-line state via USB and managing the recording to WAV
- after conversation is finished, converts WAV to MP3 using Lame library
Phone line status monitor circuit
This circuit is basically measuring voltage on the phone-line, which is is above 15 Volts (around 50) when on-hook. When any of the phones is picked-up the voltage drops below 15 Volts. This property is used to detect whether the phone line is in-use or not. The circuit is actually taken from this address and altered a bit.
Audio pickup from telephone line
In this simple part a transformer from an old PC modem i used. There are also 2x1N4148 diodes to limit the output voltage of the transformer to ~0.6V, a resistor and a capacitor. The important part is this capacitor which ensures that phone-line is never occupied by the circuit.
Microcontroller to send data to PC
Microcontroller is checking the phone line status every 0.2 seconds with a help of monitor circuit above. If the optocoupler is "closed" for more than 0.15 seconds it means that the phone line is occupied and it starts to send letter "R" (Rec) to PC application. In other case it sends "S" (Stop). This data is received by the PC where the application starts audio recording (R) or stops (S). Since the microcontroller uses serial communication to send the data, PL-2303 circuit is used to translate those signals to USB. (An entire PCB converter is used in this application, as it can be seen in the picture.) Much better way of doing this is would be with V-USB library (see these simple projects). That way we could use only one Atmel chip instead of these two (PIC + PL-2303).
Author (sent by): Trax
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Date: 02-03-2010
Lokalna verzija ove stranice: Snimač telefonskih razgovora
Tags: call, phone, pic, pic16f84, record, recorder, rs232, snimanje, telefon, telephone, usb. +add your tag
746_phone_recorder.rar
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comment [15]
- From sunlight305 on 29-08-2010 at 04:59:37
The project is great and interesting.Can you send me the source code for windows
application.Thanks very much!
IP: n/a
comment [13]
- From Jaime D. on 21-08-2010 at 03:45:19
Good evening!!
That's a great project!!!
Can you let me see your code in delphi???
I'll appreciate it.
Thanks
IP: 189.179.79.70
comment [12]
- From trax on 28-06-2010 at 11:56:55
It is all in the description. Read it: http://www.elektronika.ba/746/phone-recorder/
IP: n/a
comment [11]
- From Ravi T on 28-06-2010 at 11:41:58
Could you please tell me what does PIC 16F84 do? what are the functionality of this ID? and I
got to know that this IC is a programmable IC. In your project, are we doing any programming
for this IC.
regards,
Ravi
IP: 122.176.50.204
comment [10]
- From trax on 15-06-2010 at 13:15:27
Sorry, I have been busy. I will try tonight!
IP: n/a
comment [9]
- From Tius on 15-06-2010 at 12:44:28
I will send it later today.
Ok. I'm waiting. Please send it to my email address. Many thanks.
IP: 125.163.37.233
comment [7]
- From Tius on 14-06-2010 at 03:17:24
Hi... I interested to get the Delphi 7 source code of call recorder application. Could you send
it to my email? Thanks.
IP: 125.163.44.128
