I am using accelerometer ADXL377 to find accelerations of a vibratory roller. Before I can do this, I need to calibrate the sensor (is this true?). To do this, I downloaded an app on my iPhone (Accelerometer and the icon is a capital G with blue background). I have the app set on 30 Hz. I mounted the ADXL377 to my iPhone using electrical tape (yes, the x and y axis of the phone and the accelerometer line up). I used Cool term to collect data. I started the cool term and that app at the same time and moved the phone around and hit it on a piece of rubber (my iPhone is already busted up so its okay if it get another scratch).
I am getting very weird accelerations from the ADXL377 accelerometer and was wondering if someone could help me out. I think the problem is that my phone is sampling at a completely different rate then the ADXL377. I also am very unsure of my code. I have attached my excel sheet which has the data from my phone and from the accelerometer, and also my arduino code (it is an arduino uno).I have no idea if this code is correct or not, or if it will even work for what I am trying todo.
Also, if the iPhone is collecting data at 30 Hz, would the time column in excel be in seconds? Because time goes from 1 to 524. But I was not collecting data for 524 seconds. It was around 10 to 20 seconds.
If someone could help me out that would be awesome. Is there any other suggestions on how to calibrate the accelerometer? I have read on ada fruits website that I can drop the accelerometer at a known height and calculate the acceleration on impact. The problem with that is if the accelerometer lands at an angle, I don't know what that angle will be therefore it will be hard to calculate the forces.
Any input or ideas would help!