Digital Voice Record and Playback Project by ISD2560P

Description: 

This project is based on ISD2560P IC which allows us to record 60 seconds voice record and playback it with very high quality. As shown in the schematic, we input the voice by using an electret microphone. If a dynamic microphone is used,  R2,R3,R4 resistors and C3,C5,C7 capacitors will be omitted and microphone will be connected to 17 and 18 numbered pins directly. Since it has better frequency response, we choose electret microphone in this project.

Controlling the circuit is very simple. Sw1 switches between record and playback modes. Push button B1 is used for start and pause functions. B2 stops the process.

To record voice, first move Sw1 to record position and push B1 once. IC will start recording and during this process red LED will bright. One push to B1 pauses and second push continues recording. You can record 60 seconds by this way. To stop recording push B2.

To listen the voice recorded before, move Sw1 to playback position then push B1. During the playback process red LED will bright again. One push to B1 pauses and second push continues playing. To stop playback push B2.

Click here to download PCB and Layout Files

There are some other operating modes for ISD2560P. Mode choice is done by the 7 numbered pin of the IC. For instance if you want to play the voice repeatedly, 7 and 4 numbered pins must be connected to +5V. Another mode is recording and playing only during pushing B1 button. To switch this mode, connect only the 6 numbered pin to +5V.

Supply voltage of the circuit is +9V that is given by a 9V battery or 9V AC/DC adapter.But since ISD2560D requires +5V, we use a voltage regulator in our circuit. You can see the supply part of the circuit by 7805 regulator in the figure.

 ISD2560P IC includes an amplifier to drive a 16 Ohm speaker but the output volume is not high enough. So instead of a 16 Ohm speaker, an amplifier circuit must be connected to the output. You can see the amplifier part of the circuit based on LM386 in the figure. SP+ and SP- pins must be connected to 14 and 15 numbered pins of ISD2560D. A 100K potentiometer is used to adjust the output volume. If the output of the amplifier is connected to a 8 Ohm speaker, then much higher volume will be taken.

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Comments (5)

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Expanding recording time
written by Matthew Bumbalough, February 24, 2008

Is there any way to add something like a memory card socket to extend the recording time. For example, maybe adding a 1Gig SD card for the recorder to save the file to? That would be perfect for this project.

Thank you,
Matt

...
written by s.h., February 24, 2008

By using the data pins of the ISD, you can read the recorded data and by using an external microcontroller it is possible to write this data to a SD card. But I am not sure that you can do the recording and reading process at the same time. You should read the operation modes of the ISD2560 carefully and find out.

Technician
written by Inuwa Jika, March 13, 2008

So much interesting

Record from PC
written by Tomas, March 17, 2008

I need to record audio from a PC, how is the conection?

Thanks

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written by Hi, March 17, 2008

Once I tried to record audio from pc but pc audio output made so much noise. when I tried by using a mp3 player sound quality was good. I dont remember how I did the connection but you have only two options try this two different ways of connection.