USB/Serial Data Input Device ??

"InOverMyHead" schreef in bericht news:fOktb.1124$ snipped-for-privacy@newsread2.news.pas.earthlink.net...

sense

Bob,

What you want to do is known as data logging. A cheap (in components) solution is using the parallel port. You get whatever sensorvoltage you have, take an AD-converter to make it 8 bits binary and present it to the parallel port. The burden of timing is on the side of the PC-program. That's to say on the programmer. If you use DOS it is not that difficult but it's hardly possible to use the PC for somthing else at the same time. If you're using windows, the programming of the parallel port is a pain. Furthermore, the timing (especially for short intervals) is not very accurate as windows has a lot of other things to do.

A much better solution is taking a microcontroller. Use one that has a uart and a AD-converter on board. The micro can gathering the data and send it to the PC which can take all the time it needs to receive and store it. Windows can be programmed to perform this task in the background, so you can use the PC for normal tasks as well.

I'm sure you can find a lot of info googling for data logging.

petrus

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Further to Petrus's comments I saw a neat looking device in a computer mag - which I have just rediscoverd... The thing is called a "Personal Measurment Device" for usb i/o control/aquire etc Ad. says 8 single ended or 4 diff. 12 bit A/D i/p, 2x10 bit analogue o/ps, and a 32 bit ext event counter. Also 16 digital i/o and ext trig. Apparently the thing can be controlled by your software in "any Windows lang". Of course do they put a url anywhere or even a co name - can't see one... it *may* be "MCC". The mag has one of those circle a number and send it back for further info things - which I never do. hth

In article , snipped-for-privacy@hccnet.nl mentioned...

People overlook using the game port to do simple analog input. You can put a 30k ohm thermistor across the pins that normally have the joystick pots, and read the thermistor value, and translate that into temperature. Or use a CdS photocell instead of the thermistor to sense light (radio snack has them). You can put a switch across the joystick button pins to get an on/off input. This is probably the least expensive way.

You can buy a DMM from radio shark that connects to the PC thru a serial port. It comes with software that allows you to read the voltage or current or resistaince, etc. For more info see URL

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bit

digital

and

Nuts & Volts magazine has a lot of that kind of stuff in the ads in the back.

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sense

What you need is a 'Labjack'.

USB powered and you can daisy-chain them too. HTH, JB

or

Tom Woodrow

Try

for the DI-194R3 DA at $24.95, then select your input type.

GL Tom

sense

and

talking

great.

solutions?

Bob,

B&B Electronics has an analog to serial module for about $70 US Kind of experience

DLPDesign has a USB example design with a DS18S20 Temperature sensor for $50. With the driver from FTDIchip.com, you can access this using a virtual comm port. (serial).

If you need to import serial to Excel, I can provide an example spreadsheet that uses Excel macros (VBA) and the MSComm Control, which is available on the Net. Drop me a line if you are interested.

If you want to build something, KitsRUS has a datalogger kit:

Hobby Engineer sells this kit for $29.

snipped-for-privacy@yahoo.com

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - >What am I looking for? I don't even know what to call it. But it would sense

At least on the old ISA bus gameport adaptors, and those integrated on older I/O cards (the 558 based ones), there is less than 8 bits, when you reslove out the play in the A/D convertor used.

Any Windows 98 or higher though. You can get simple USB I/O adaptors that use FTDI or Cypress chips. If just serial any micro can do. If you need USB, you could use the micro as if you did use serial , but use a USB RS 232 adaptor.

Try the intro level serial ADC from DATAQ Instruments

It has four 10 bit, +/-10 volt ADC channels and two digital channels for control. It comes with Windows software so you can use it as a chart recorder. I spent a number of hours exploring ways to measure light and temperature with it. If you do any programming, an ActiveX control is included so you can access the unit from Visual Basic or VBA (in Excel, Access, etc).

You can read about the unit here:

It's US$25 and I think it's worth the money just for the data acquisition education you'll get while exploring it.

More about me:

VB3/VB6/NSBasic Palm/C/PowerBasic source code: Drivers for Pablo graphics tablet and JamCam cameras: johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

Try these links...

sense

sense

How about the Maxim DS1615, a one chip temperature recorder. You can dump the values to the serial port later.

Wim

Wow - you guys are great. I'm going with the Hobby Electronics' K145 Temp Data Logger kit. Thanks again for all the leads. I've spent HOURS getting happily sidetracked. Oh the possibilities . . .

Bob

sense

Yes, this is generally called "data logging", and there are getting to be thousands of ways of doing it. If you don't want to dedicate a desktop or laptop computer to the job, you can buy dedicated loggers that do their thing for minutes to years, after which you download the data to a computer. Onset

makes self-contained loggers for a wide variety of variables (temp, light, humidity, events, voltage, etc.) for both dry and wet conditions. They're rugged, relatively cheap, last forever, and are a breeze to use. If you are serious, with serious money, you can go to companies such as Campbell Scientific but that's outside the realm of "hobby". One thing I want to explore is using a cheap Palm organizer (Palm IIxe's are getting cheap on eBay) and something like the "MELD" data acquisition board ) to log, say, four channels of temperature over a period of months. National Semiconductor makes the LM34 and LM35 temperature-to-voltage converters, available through DigiKey for cheap, and you could instrument your house (or compost pile or whatever) for less than $100.

Going off-topic (OT), anyone got an inexpensive solution to this related problem? Is there something like a Palm OS terminal emulator that can be programmed with a macro to send out a character every, say, 10 minutes, then log what comes back to a text file? I don't want to tie up a full-size computer with this, but it needs enough smarts to send and receive short strings, know roughly what time it is, etc. A time stamp would be great, but not absolutely necessary. A used Palm organizer seems like a great platform for this sort of thing (maybe rigged with larger batteries to run for long periods). This could be used for a bunch of applications, but what I have in mind at the moment is this: Quantum Research Group makes a nifty capacitive linear position sensor chip

available for a few bucks from DigiKey. You can configure it to chat on a one wire serial line: You ping it with a short pulse train (a single character should do, if you choose the right character), and it responds with a

16-bit position measurement (two 8-bit bytes with the usual start and stop characters). Whatever terminal emulator I use would have to be able to deal with *any* value from 0-255, which might be tricky, since there be dragons such as ESC, RET, etc. that will cause weirdness in the logged text file, but most of that could be handled later. I've programmed in a handful of languages and systems, but haven't done any Palm OS programming, and would like to avoid reinventing the wheel if possible. There is a LOT of Palm shareware out there, but I haven't located what I described above. Ideas? Pointers? Thanks.

-Ted

I've used the Palm m100 running hotpaw basic to talk to an OOPic data logger. Talk about simple and very capable, and very, very cheap.

DLC

: Going off-topic (OT), anyone got an inexpensive solution to this : related problem? Is there something like a Palm OS terminal emulator : that can be programmed with a macro to send out a character every, : say, 10 minutes, then log what comes back to a text file? I don't want : to tie up a full-size computer with this, but it needs enough smarts : to send and receive short strings, know roughly what time it is, etc. : A time stamp would be great, but not absolutely necessary. A used Palm : organizer seems like a great platform for this sort of thing (maybe : rigged with larger batteries to run for long periods). This could be : used for a bunch of applications, but what I have in mind at the : moment is this: : Quantum Research Group makes a nifty capacitive linear position : sensor chip

available for a : few bucks from DigiKey. You can configure it to chat on a one wire : serial line: You ping it with a short pulse train (a single character : should do, if you choose the right character), and it responds with a : 16-bit position measurement (two 8-bit bytes with the usual start and : stop characters). Whatever terminal emulator I use would have to be : able to deal with *any* value from 0-255, which might be tricky, since : there be dragons such as ESC, RET, etc. that will cause weirdness in : the logged text file, but most of that could be handled later. I've : programmed in a handful of languages and systems, but haven't done any : Palm OS programming, and would like to avoid reinventing the wheel if : possible. There is a LOT of Palm shareware out there, but I haven't : located what I described above. Ideas? Pointers? Thanks. : -Ted

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* Dennis Clark         dlc@frii.com                www.techtoystoday.com   * 
* "Programming and Customizing the OOPic Microcontroller" Mcgraw-Hill 2003 *    
============================================================================

I second using hotpaw basic

You get a 30 day trial of the download.

It's the most "bang for the buck" for small programs (at $18.95) - unless you want to learn C on the Palm. OnBoardC is free and generates executable files on the Palm. Hotpaw is an interpreter and your program will not be as fast as a compiled C program. However, the learning curve for OnBoardC is much steeper than for hotpaw.

The only problem I can see with hotpaw is whether it handles a 0 byte or uses it as a string terminator. If you can define a byte array (instead of a string) as the destination of the incoming bytes, it should work OK.

I've been using another development tool for about 6 months and have forgotten much of what I knew about hotpaw :-(

The full documentation for hotpaw, including a tutorial, is available at the link given above.

More about me:

VB3/VB6/C/PowerBasic source code: Freeware for the Palm with NS Basic source code: Drivers for Pablo graphics tablet and JamCam cameras: johnecarter at@at mindspring dot.dot com. Fix the obvious to reply by email.

Thanks for the great pointers, guys. For most of these applications, an interpreted Basic should be fast enough, so HotPaw should be fine. I took a look at the documentation, and it looks like all the pieces are there. I just need to cut loose the time to try it out.

Yes, looking over the documentation (basic-manual.txt, quickref.txt, readme.txt, and yb_tutorial.txt), it's clear that I could send the individual bytes, but it's not clear how the non-printable characters might behave. In "quickref.txt" I find:

This implies to me that the "get$(#5, n)" command will be handing me a string, but I'm not clear on whether this could be simply handed to a string function to extract a numerical value to put in a byte array, and whether zero is interpreted specially. One way to find out is to try it, but it would be nice if it were documented explicitely. For the project I outlined earlier, a 16-bit range provides many opportunities for the "get$" to get confused.

-Ted