Small Pocket Computer For Data Logging And Control

Thanks for the response.....are the data and address lines brought out to the I/O port?

TMT

Mark Fortune wrote:

you can pick up older palm pilots on ebay pretty cheap these days

Pick a device with a USB port and I bet you can find an off-the-shelf device that does sensor inputs and contact closure outputs, somewhere.

If you get a PDA that runs Microsoft CE you'll be able to sevelop your software in a very standard enviroment.

OTOH, the Nokia 770 looks neat (about $400) and it's Linux-based. Sourceforge.net shows that people are beginning to develop apps for it.

: Pick a device with a USB port and I bet you can find an off-the-shelf : device that does sensor inputs and contact closure outputs, somewhere.

The problem is that PDA:s are typically USB "clients" (to sync with a "host" PC), and while the USB gadgets to add sensor inputs are intended to connect to a PC, they are also "clients". Two clients cannot connect.

How do I know? I use Palm PDA to read and plot data from a logger (with my own application). It works over RS-232 data connection. As serial Palms are getting rare, it would be cool to be able to switch over to USB, but unfortunately seems to be impossible...

-Tapio-

This is at least partially incorrect. There are actually several PocketPCs that are USB host capable. For example: Toshiba E740 (which I own) and the Dell Axim series. I believe that several other Toshiba and Dell Series PPCs also have USB host, but I can only personally attest to these two. There are also several iPaqs that I see claim to have USB host. You will need to create a driver for your device though. I have only been able to get USB drives and mice to work so far with my E740.

And even if your PocketPC does not have a USB host, you can buy compactflash adapters that provide that capability.

Of course, if you have a SD or MMC port, you have SPI, and with compactflash, you actually have addressing and I/O. Obviously since these ports were mostly meant for storage, you will need to create drivers for them since the operating system (usually) only supports the storage classes.

I would agree that finding a PDA with serial is a better choice though since it is easier to just send raw serial commands than creating a usb stack and driver.

Another possibility is a palm pilot with the ethernet cradle.

Scott McDonnell

I originally used an HP48GX graphing calculator as it had an RS232 port. HP is coming out with an HP50G with USB/RS232 (available outside US now) and is about $130. 4xAAA batteries should last considerably longer than PDA equivalent. Programming in ARM ASM should be wicked fast. Also, calculator has SD card slot with FAT32 capabiliy, so a big data heap is possible.

I'm looking at ways of interfacing the 50G (and 48GX) to a Fluke 189 logging multimeter for DA.

Cheers, Scott