16 Bit Data Logger- Microcontroller and ADC question

I am working on a Senior Design project involving the design and
construction of a 16 bit data logger. We would like our unit to have
8 input channels, 16 bit resolution, and USB interface (if possible).
We would also like all components to be through hole mounted to
simplify hand assembly. All measurements taken will be low speed and
size of the unit is not a major concern (within reason)

Are there any ADCs, microcontrollers or combinations of these that you
would recommend? We are focusing on cost and simplicity of design and
programming (because we don't have a lot of experience in this area).

Thanks for your help,
Tim

 

None of that should be a problem except "through hole mounted" IMHO.
Your selection of micros is much wider if you don't insist on through
hole mounted for that part. You might consider using an adapter like
these http://www.accutekmicro.com/press_details.cfm?Press_ID=18 to
simplify construction.

I don't have a specific micro recommendation, but a technique you could
use for selection. FIND TOOLS FIRST! The greatest micro in the world
won't help you at all if you have to use a cranky assembler or flaky
compiler. On the other hand, if you have really great tools, rolling
your own USB support (rather than having it all in hardware) wouldn't be
quite as painful as it might be otherwise. Just MHO. Good luck!

Ed

 

There are so many devices out there. If you went with TI data converters,
there are many 16-bit ADCs, some with through-hole pinouts. The
surface-mount packages are much cheaper and have better specifications, for
instance there are some available with 8 input channels. Parametric table:
http://focus.ti.com/docs/search/vpa...param_table&templateId=4&showAssociated=false

I suppose you'd want a microcontroller as well. Many of the ADC chips have
an serial interface (synchronous) which is simple to connect to most
microcontrollers. If you want USB functionality, there are many USB
microcontrollers available. Motorola makes some useful ones, good for
peripherals and not overkill for a simple data collection system. If you
decide to incorporate USB, investigate the HID protocol. They are relatively
simple to program for on the embedded device, and you do not need to write
an actual driver on the host computer side; simply use readfile commands and
get your data. If necessary you could make your device appear to be a
keyboard, and when a button is pressed on the device, it would type all of
the voltage levels with carriage returns in between; seamless input to an
Excel spreadsheet or other application.

I did a USB device for my senior project, and it wasn't easy since I too
hadn't had much experience. It worked though. Given another chance, I would
probably use one of FTDI's USB interface chips instead. They add another
device to your board, and you can't claim to have programmed the USB
interface, but it would leave a lot more time for correct documentation.
What use is a perfectly functional device, if the report doesn't convey that
fact?