Voice Recording and Playback Circuit

You can make a voice recording and playback circuit using the easily available IC APR 9301. The circuit can record and playback the voice up to 30 seconds. It can be used in automatic answering devices, door phone, etc. The IC APR 9301 is provided with the circuitry capable of storing and reproducing the sound without using any microcontroller or some other software. No external ICs are required in the operation of the voice recording.

If we use all this kind of software the device may suffer from some virus, so by avoiding the use of microcontrollers and additional software we can able to operate the device free from errors. This process is based on Single-chip, and having high-quality voice recording & Playback solution There are some numerous remuneration in using a voice recording which helps give us security when we wish to protect ourselves, it works as a prompt, and this application includes the processes like the recording of conversation through different techniques through which they can record hours of conversations.

Digital Voice Recording

There are different kinds of voice recorders, the digital voice recorder is one of the types of voice recorder in which we can able to record hours of conversations. There are so many benefits in using a digital voice recording which helps to provide security when we want to protect ourselves, it works as a reminder, and this application includes the processes like a recording of conversation through two techniques which might be pen voice recorder or wristwatch voice recorder through which they can record hours of conversations.

This technology is most useful in day to day life, the voice recorders which gets recorded from the wristwatch voice recorder and pen voice recorder can be easily transferred to the computer through the USB key. This allows creating the audio or voicing recorded files of conversations, which can be copied and forwarded easily. These can be placed in some other devices like’s hard disks, CD drives, pen drive, and these copied files are easily forwardable within few minutes these applications are mostly helpful for students, you can send this conversation as notes to those who have missed their previous classes. This device consumes less amount of power supply.

Application of Voice Recording:

About APR 9301

IC 9301 is a versatile 28 pin IC with nonvolatile flash memory. It can perform around 100 K recording cycles and can store the memory around 100 years. It is based on the Inbox proprietary analog / multi-level flash nonvolatile memory cells. The memory cells can store more than 256 voltage levels. The IC is a low voltage version and requires only 5 volts and 25 mA current for its normal working.

During the recording process, the LED device is associated with its pin 25 for blinks which indicating the recording.

The sampling frequency of IC APR 9301

A. 20 Sec 6.4 KHz
B. 24 Sec 5.3 KHz
C. 30 Sec 4 KHz

Working of the IC

The IC APR 9301 performs two modes of operations- Recording and Playback modes. The IC gets the recording voice signals through the Mic connected to its pins 17 and 18. Any kind of good quality condenser mic can be used. By closing the switch S1, the recording mode will be started. A single voice message of 20-30 seconds duration can be recorded easily. The IC remains in the recording mode as long as is Red L pin 27 is grounded. During the recording process, the LED connected to its pin 25 blinks indicating the recording. During the recording mode, the Speaker driver will be in the mute position. Required operating current is 25mA (typical, no load).

When the 20 cycles are over with the last memory, the recording process automatically terminates. The recording time can be increased to 30 seconds by changing the value of the OscR resistor R1 connected to its pins 6 and 7. If the value of R1 is 52K, 20 seconds recording will be obtained. If it increases to 67K, then the time can be increased to 24 seconds. A maximum time of 30 seconds can be obtained using an 89K resistor as R1.

During the Playback mode, the input section will mute automatically. By closing the switch S2, the recorded message will start to come from the speaker from the beginning of the message. After completing the Recording or Playback function, the IC enters into the Standby mode.

The circuit can be assembled on a common PCB. IC APR 9301 is a sensitive 28 pin IC which requires a 28 pin IC base. Solder the IC base carefully without any shorting between the pins. Connect the IC in the IC base only after checking the circuit after its assembly. Closely check the pin connections before powering the circuit. Use a 5-volt regulator IC-based Power supply for the circuit. Use a 2 inch 8 ohms good quality speaker to get a clear sound. By pressing the switch S1, Recording can be done. The mic picks up the sound signals (Speech or Music) and passes the same to the IC where the voice signals will be stored in the memory cells. By closing the switch S2, Playback starts and the recorded message will be heard through the speaker.

Features of IC APR 9301:

• Power supply voltage ( Vcc ) is about to:5.5 min,6.5 max
• Temperature storage of this IC is:–65min, 150 max
• This process is based on Single-chip, and having high-quality voice recording & Playback solution
• No external ICs are required in the operation of the APR 9301 ICs.
•  external components required are less all the devices are connected internally
•  This is a Non-volatile device so this is mostly based on flash memory technology
•  Battery backup is not required in this device
• 100K record cycles (typical)
• 100-year message retention (typical)
• Required operating current is: 25mA (typical, no load)
• Standby current is about: 1uA (typical, no load)
• Low power consumption
• Non-volatile Flash memory technology

Now you have a clear idea about the voice recorder and playback circuit if any queries on this topic or the electrical and electronic projects leave the comments below.

Photo Credit

• Digital Voice Recording by encrypted-tbn0.gstatic
• BoardVoice Router by encrypted-tbn0.gstatic