Alarm Clock using Arduino 16.000mhz cristal


I am very new to the Arduino world.

A friend of mine want a special alarm clock. He wants an alarm clock with 27 alarms of 3 seconds each with no LCD or anything else...only the arduino and the speaker. To set the arduino to start at 12 am when you plug it to a battery.

I made the program in C++ to have an idea of how it's going but i don't know how to implement on the Arduino.

It's possible this without using a 32.768kHz crystal and a DS1307?

Thank you and sorry for my english :)

Most Arduinos use a ceramic resonator instead of a crystal. They are only accurate to a couple of minutes per day. In 30 days they could be off by an hour. You can probably replace the resonator with a precision crystal to improve accuracy.

The US power grid uses precise frequency control over the medium term. You could use an AC power supply to trigger an interrupt 60 times per second and accumulate that count to tell time.