This is a DC-DC buck-mode power module, with input voltage range of 3V - 15V and fixed voltage / current at fixed 5V / 600mA . Working frequency can reach 0.5 MHz . The module has high conversion rate and small size, easy to incorporate.
The Arduino WTV020-SD MP3 Module is a voice recording module with 1GB SD Card storage capacity. You can upload WAV and AD4 format files that conform to FAT formatting. It supports 6KHz to 32KHz, being 36KHz for AD4 files and 6-16KHz for voice sampling rate (Audio Sampling).
This Voice Recognition Module with Microphone for Arduino can recognize up to 15 voice instructions and be suitable for most cases involving voice control. With this module, we can control cars or other electrical devices by voice.