Project Proposal

This semester, our group plans to design a PCB to realize an MP3 alarm clock. This device will be equipped with flash memory and a USB interface to allow the user to download songs onto the clock from his personal computer. The project is made up of the following subsystems:

Clock: The clock is a standard 12-hour AM/PM real-time clock that the user can set to local time using the user interface. The user can choose to have no alarm, a beep or buzz, or an MP3 play at he preset alarm time.

Display: The time information and alarm status will be communicated to the user via a common LED display package.

Human Interface: Eight controls are provided to the user for setting clock features as follows: · Set time button · Set alarm button · Snooze button · Hour-increment button · Minute-increment button · Volume (dial or up/down button set) · Alarm off/ Buzzer/ MP3 selector · Play/Stop button

Player: Onboard memory will hold MP3 songs, which will be sent to an MP3 decoder/DAC for playback.

To allow for at least a one-song capacity, the PCB will require a minimum of 8 MB of onboard memory. The MP3 data will be transferred to the PCB through a USB interface with the user's computer via a Windows-compatible program. The alarm duration will be 15 minutes unless the user turns off the alarm or presses the snooze button. There will be a ten-minute interval between alarms following a snooze request. The alarm (buzz or music) will be played through an onboard, volume-controlled speaker via a mono channel.

Main Block Diagram

EZ USB: forms connection between computer and MP3 alarm clock; has an internal microcontroller that will control the interaction of the system's components

LCD: displays the time and other messages

EEPROM: holds clock settings, song memory pointers, volume settings

RTC: real-time clock

SmartMedia Memory Card: holds the MP3

I/O Expander: allows for multiple input buttons on the I2C bus

Audio Subsystem Block Diagram

MP3 Decoder: converts MP3 file to digital audio

DAC: converts digital audio to an analog signal

Audio Amplifier: increases the power of the audio signal