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Logging Bluetooth Accelerometer Data on a PDA?
sessha asks: "I want to log data from a Bluetooth Accelerometer (actually 5) attached to different parts of the body. How one would go about logging the data onto a bluetooth compatible PDA. I know quite little about PDA OS's, but the main concern is functionality - it doesn't matter if it is PalmOS or Windows CE or whatever. The Linux and Windows directions for data logging are shown, but how would one best go about this on a PDA? Also, it would require at least 256 MB storage, preferably more, since this will be recording 300 of these ASCII strings a second for a number of days. Suggestions as to the best equipment and software to use for such an endeavor would be greatly appreciated."
Is indeterminate write times. You're most likely working with flash memory. Flash memory write completion times will vary depending on the device, the block size, and the wear-leveling algorithm used. You probably won't have much control over anything other than block size. You'll have to think about when to close and open the file as well. Frequent file commits will improve recovery from errors, but will also probably increase write times.
This is really a job for an embedded computer engineer. If there's money, safety or reputation at stake, I urge you to find one to help you.
"Eve of Destruction", it's not just for old hippies anymore...
But there is no good way to get data into that iPod device. You could do a bunch of hardware hackage, sure- but that's is a lot of work. You'd probably be a lot better off with one of those PCMCIA HDs- the kind the iPod has- in a PDA, along with a huge battery extender. Either you are running your bluetooth off of the iPod's battery (thus killing the batt) or you have even more hardware hackage to do.
WinCE would be the easiest thing to do this in. I've done a lot of PDA programming, and I'd take WinCE any day, over PalmOS or Linux. There are a lot of options for programming, you've got a real OS, stable bluetooth [1], lots of libraries, etc. My interest area is largely in programming a PDA on a PDA, with no desktop as a part of the developer process, but that is just me. No need to spend a ton of time writing a big, ugly and finnicky C/C++ app- WinCE has a lot of good scripting languages available, including Ruby, Perl, Python, Dialect [2], Scheme, Lisp, BASIC, and many others.
[1] The Zaurus has some problems with the bt hardware available- maybe the new SL-6000 series would be good... but then again, just because the Zaurus comes with Bluetooth it doesn't mean it works, at least with Sharp at the helm of such a device. But there's a good chance it does.
[2] Dialect is my personal fave, a prototype-based OOPL. Kind of a cross between NewtonScript (object model) and Python (syntax) with really good support for dealing with the underlying WinCE or regular Windows OS.
Working toward a usable PDA environment in the spirit of Newton OS: Dynapad
Simputer has a built-in Accelerometer and it runs Linux. Since this device already has built-in support for accelerometer, it should be relatively easy to add support for more using the SDK. Also, simputer can use USB flash memory. It also is one of the rare pda-size devices that has 2 USB ports (one master and one slave; most PDA's only have a slave USB where you can not plug any other usb device). It also has IR port. I am not sure how bluetooth would fit in but it shouldn't be too difficult with a device with such features...