This sound/voice recorder module is base on the ISD1820 integrated circuit, which can record multiple sounds or voice messages through the on-board microphone. The audio is stored in nonvolatile memory.
The sample rate and recording length can be set up by changing a resistor. The resistor R4 onboard has 100kOhm, setting the recording length to 10s with a sample rate of 6.4kHz. By replacing this resistor, sample rates from 3.2 to 8kHz can be selected, resulting in a max. the recording time of 8 to 20 seconds.
The ISD1820 module’s function can be controlled by the onboard pushbuttons, or through its control pins, connected to a microcontroller like Arduino, STM32, or PIC, for example.