Creating a device to measure activity levels of slow-walking people


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! :slight_smile:

well, arduino can use pretty much any stanard sensor, pick your sensor. The GPS module will interface via serial, that's easy enough. The rest will be TWI or I2C probably (just a variation on serial), the LCD you'll do with 4-bit parallel and you'll need a couple of switches for user input I would think.

What you describe really isn't all that complex, probably the largest gotcha is keeping two linked wirelessly to sense incline. I might suggest just adding a wired sensor to the upper arm, the device being torso-mounted. Relative position is going to be the largest pain the design.

"Shields" are just boards that make connection of various addons easier. An xbee shield makes it easy to plug in an xbee module, an ethernet shield adds an ethernet controller.

Any arduino is up to this job.

Thank you, that was very helpful! :)

Arduino as a language is pretty much a scaled back version of C.

You are going to want to use several of the libraries commonly used, specifically I2C and LCD, and probably use a software serial port for the GPS. I think there’s even a library for parsing GPS data automatically, as well as for the accelerometers commonly used and SD read/write.

Arduino libraries make dealing with most of this pretty simple, it’s amazing at times how many well-written Arduino libraries there are out there.