Voice Recorder and Playback Circuit

With this circuit, you can record your voice and play back the same for 20 seconds. The circuit is ideal for door phones, automatic answering devices etc.APR 9301 is used in the circuit which is a data storage and retrieval IC without any micro controller programming.

The IC requires minimum components to create a voice recorder. The IC has non volatile flash memory technology with 100K recording cycles and 100 year message retention capacity. The IC utilizes the Invox proprietary analog / multi level flash non volatile memory cells that can store more than 256 voltage levels. It requires a single 5 volt supply and operates in 25 mA current.

APR9301 Datasheet

Mode of operation

 1.     Record Mode

The LED glows when the IC records the voice obtained through the Mic. A single voice message up to 20 seconds can be recorded. The IC remains in the recorded mode as long as the RecL pin 27 is grounded. Recoding will be terminated with the last memory when 20 seconds is over. The Speaker driver will automatically mutes in the recording mode. By changing the value of the OscR resistor R1 it is possible to increase the recording period as follows.

  1. R1 52K 20 Sec.
  2. R1 67 K   24 Sec
  3. R1 89 K   30 Sec.

 Play back Mode

By pressing the play back switch, the play mode starts from the beginning of the message. The input section will be muted during play back.

   Standby Mode

After completing the Record or Play back function, the IC will enters into the standby mode.

    Sampling frequency

20 Sec 6.4 KHz

24 Sec 5.3 KHz

30 Sec 4 KHz

28 Pin IC requires IC base.


Press ,switch S1 and speak through the Mic or record music. LED will glow in the recording mode. Open S1 after recording. Use a small condenser Mic

 Play back

Close S2. Recorded message will be heard from the speaker. Use a 2 inch 8 Ohms speaker.

Power supply 5 Volt regulated supply or 6 volt battery.

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