MSP430 Accelerometer microSD Datalogger

MindForge put together an EMG logger to study and track his dad’s Parkinsons disease. He moved away from it as it was not impractical to wear EMG electrodes all day. However, the project was a good base to build his datalogger project which logs accelerometer values to an SDCard.

I moved away from the EMG idea and began working on a low-cost low-power consumption accelerometer datalogger instead.

Datalogger output

The datalogger is built around an MSP430G2755(32 KB FLASH and 4KB RAM). An Analog devices ADXL335 accelerometer tracks movement which is logged to an SDCard using Elm Chan’s FatFS library.

Right now the MSP430 samples the 3 ADC pins about 40 times per second, stores the values to a buffer, then appends that buffer to a file in FatFS. I wrote some python with a GTK UI to make going through the data easier usingmatplotlib. I have a repository for that project here. I used numpy and scipy to do things like filtering and smoothing the signal.

Links

• Via: MSP430 Accelerometer microSD Datalogger
• Order the gerbers here