ISD4004 based voice recorder

Jun 8, 2012 by Atmega Editor

So far we have seen various devices that are talking, such us cars, dolls etc.This project is also like one of them. you can use it in various projects such us IVS, robots etc.

There are various voice recording IC’s. They have different recording time and sampling frequency. Most of the IC’s can record less than 1min of sound.

ISD4004 can record 8min to 16mins maximum. If you select high sampling frequency then you can record a max 8mins at high quality. This project gives you a voice recorder based on this chip.

You can’t use this IC without a microcontroller since it works on SPI communication. So you need a microcontroller to play/record the audio. Here ATmega8 is used to play and record the chip. This is the pin diagram of the IC ISD4004
This IC works on 3.3v, so we need a regulated 3.3v using LF33CV. The audio output from the Voice0 chip is amplified by an audio amplifier. This amplifier is done with Lm386.
If you want to give audio from PC, then select the first circuit and connect a 1kohm resistor in series with the input.