ECE 4760: Final Project

AVR 16bit Stereo Wave Player

Simple, Cost-Effective, CD Audio Quality

Wancheng Zhou (

Introduction    top

This project aims to implement a cost-effective wave player based on AVR (ATmega / ATiny Series) with CD-Audio Quality, which can play 8-bit/16-bit Mono/Stereo standard RIFF (Resource Interchange File Format) wave files.  This project can be applied into many applications such as bus / subway auto-annoucing system, elevator voice indication system.

Current solutions to these kinds of “announcing system” are limited by the OTP (One-Time Programmable) voice chip with small capacity (normally use EPROM as storage media), not to mention the relatively expensive price (the price of OTP voice IC is determined by it’s capacity – voice recording time, normally 10s~200s). For instance, the OTP chip AP89010 (manufactured by APlus) is $0.48 (10 seconds OTP), and AP89341 is $2.43 (150 seconds OTP), and one announcing system may use multiple voice chips (2-10pcs) which also results in the complexity of hardware design. On the contrary, the price of standard SD card is going cheaper with the rapid development of storage technology, 512MB SD card (Kingston) only needs $3.65. Compared to OTP chip, 512MB storage can hold as many as 128 songs with MP3 format, can contain 10 lossless songs (WAV format), and the key point it that SD card can be easily formatted, songs or recorded files can be modified at will – as long as you have a PC supports FAT filesystem.

As mentioned above, the announcing system using OTP chip solution has a complicate circuit – different audio announcements need to be played from different chips, the control logic is quite a burden which definitely increase the circuit complexity including the PCB area. Quite the opposite, our system only need 6 main wires (SPI bus: 4 wires, PWM output channel: 2 wires) to play the songs or any recorded wave files. AVR chip can be purchased as cheap as $4 (ATmega328). So the whole system can be very cost-effective.

Final foot and wrist modules