I need help with creating device that will be able to play sound (can be recorded or from mp3/wav...) at certain time, for example at 8:00PM, 8:15PM; 8:30PM ...until 5:00AM. Device must be powered from battery and must be working for more than 2-3 months. Sound is about max 10 seconds and it should not be loud but also not quiet. I found that for directly recording can be useful ISD1820 but then I need to set relay and clock. Then I found VS1003, and I think that this chip can be able to do that without setting relay and clock. If anyone can help me or know something better I would really appreciate that.
Instead of using a VS1003 and a micrcontroller, you could do that with just a VS1005G using the internal flash. The VS1005G has internal real time clock, and the player software and the short MP3 file(s) could all fit in the internal 1 megabyte flash. You can also add SD card or external (nand) flash to play longer files. When you are waiting for the RTC alarm, the VS1005 chip just uses a few microamperes.
The VS1003 or similar module + a RTC Module + a microcontroller like a MSP430 Launchpad or Arduino plus a transistor or two is all you need.
The microcontroller and RTC can work with low voltages, and will be asleep most of the time. Heck, a microcontroller acting as a RTC would work as well.
As a quick and simple solution, I would personally go for a Raspberry PI with a Real Time Clock module for accurate time keeping: if you want the drift to be maximum 1min at the end of 3 months, that's 7 parts per million which is quite low for standard crystal oscillators. You can also get rid of the RTC module and use a NTP (network time protocol) time keeping instead if your PI is going to be connected to a network at all times.
However, despite the fact that it enables you to use NTP to essentially get your system running forever once plugged in mains, if battery operation is a hard requirement (quite power hungry, it definitely won't run off a reasonable battery for 3 months) you can stick with a RTC with any simple-to-use microcontroller + SD card and MP3 decoder modules (e.g. Arduino + shields).