1. ECE 492 - Computer Engineering Design Project
Step Counter Music DJ
Troy Davis and Caitlin Smart
2013
Overview
Step Counter Music DJ’s motivation is to play music for a jogger that would have a similar beats per minute (bpm) as the jogger’s step rate. The joggers step rate is measured from an accelerometer. The bpm of the song is pulled from the song title and is compared to the steps per minute in software.
User Interface
When the accelerometer is at rest, the song with the lowest bpm is automatically played. Once the accelerometer starts moving, it takes 25 seconds to get an accurate steps per minute reading. This steps per minute is used to pick the next playing song when the song ends or when the far left button is pushed (KEY3). The LCD screen displays the steps per minute (spm) and the currently playing song. The volume can be controlled through the speakers.
The software is implemented so the song will play if your are 10 bpm within its range. For example, if you want to choose a song with 160 bpm you’d have to move the accelerometer at 150 – 169 bpm. It should be noted that the songs do not have to appear in order on the SD card for the software to correctly choose a song.
Design Considerations
I2C bus contention due to the use of two bus masters led to the adoption of an isolated component design strategy. Use of the FPGA allowed the creation of a secondary I2C bus independent of the DE2 I2C bus.
The µC-OS II RTOS allowed implementation of individual tasks for accelerometer and audio control. Synchronization of task information was done through the use of message queues and semaphores.
Fig. 2 Complete Project
Functionality
Accelerometer measures x motion interrupts
WAVs are read from SD card and decoded
Song is selected from accelerometer pace
Song is played through headphone jack from audio codec
Fig. 1 Hardware Diagram
Department of Electrical & Computer Engineering