I was wondering if I could get some advice about where to start with creating a device to measure activity levels of slow-walking people.
I would like to use an Arduino microcontroller along with a triaxial accelerometer (+/- 2 G would probably be good, with pretty high precision because I need to measure the slow walking accelerations accurately). In addition, I would like to have an external memory (such as an SD card) and wireless transmission of data so I can transmit the raw accelerations to a PC. I am also looking to add in a gyrosensor to sense incline of a lower/upper limb and a gps to track location. Finally, I would like to add in an LCD display to display relevant information to a user.
So far, I've heard using an Xbee would be good for wireless transmission of data, but I don't know too much about anything else. I've programmed a different microcontroller before in C along with an LCD display, so I think learning to program an Arduino would be pretty simple.
Any ideas on what kinds of components I should be using to interface with an Arduino microcontroller? Also, I was thinking of getting 2 microcontrollers, one that is very capable (I'm not sure whether to choose the Uno or the Mega or something else) and one that is miniature and a good size for a limb sensor (maybe the Nano). What would be some good choices? I've also read a bit about shields but I don't really understand too much. Some help would be great!
I'm quite new to electronics so I apologize if I'm asking some trivial questions. Thank you!