Easy datalogger?

[PEU]

I want to build an easy datalogger for runtime tests, any ideas? It should connect via rs232 (or usb:)) to the pc

Thanks


Pablo

 

[jtice]

ive been wanting this one really bad, but im topo cheap to get it lol
http://www.labjack.com/labjack_u12.html

I hear they are very easy to make though, if someone could just provide the info needed, im sure we could make them.

 

[Roy]

Check Radio Shack for a data logging DMM with a RS232 serial port. It will come with plotting software.

Look here.

 

[PEU]

Roy, I have one of these, was looking for something smaller, less bulky.


Pablo

 

[jtice]

I was gonna get one of those, but I want to me able to monitpr more than one variable at once, so I have been holding out for the USB LabJack one, but, I should just get the radio shack one, sence ill never end up getting the USB one for a while,, always something else to spend the $120 on /ubbthreads/images/graemlins/frown.gif

 

[MikeLip]

Check this out;

http://www.circuitspecialists.com/prod.itml/icOid/4668

I use this guy as a bench meter at work, and the RS232 software works just fine. The company is reliable too. Runs off batteries or line power.

Mike

 

[jtice]

That seems really nice, like the style of the beanch unit.
Though, still it has that same drawback, of only being able to log one thing at a time. /ubbthreads/images/graemlins/frown.gif

 

[MikeLip]

OK then, how about something like this;

http://www.dataq.com/194.htm

I use a lot of these at work. You will have to calibrate them with a DMM to get a usable unit out of them, but your $10 meter can do that - the software will scale the readins for you, if you know what the input is and how it relates to the real world. Get a 5 volt regulated wall wart power supply if you need to supply a stimulus, and you're done! 4 channels at 10 bits resolution, 256 samples/sec maximum divided among the four channels - the fewer channels you use, the more often you can log, if you see what I mean. For runtime, you probably don't want to record more often than once every few seconds anyway, so the sample rate is way more than sufficient. It's great - anyone looking for cheap data logging ought to get one.

Oh, yeah - it's $25!

Mike

 

[PEU]

nice find, Mike.

If no one offers a better solution, im in for one !!!

Thanks


Pablo

 

[cy]

nice find at $25

 

[jtice]

VERY nice find !!!!!!

but, looky what I found... hehe http://www.dataq.com/products/startkit/di148.htm
thats the 8 channel USB one.

Though 4 channels would be nice, the USB part is great.

Im gonna get one or these, just gotta deside, these are sweet.

 

[jtice]

Just ordered the 8 channel USB version fr $55 shipped /ubbthreads/images/graemlins/smile.gif

 

[MikeLip]

The USB one is great, but did you notice that to use the full sample rate you have to buy $100 worth of software? Otherwise it's just 256 samples/second. Nothing wrong with that of course, and the USB means you can just plug it in and out and be more likely to have it work every time, unlike RS232 comms which can be messed up by doing that.

I hope you guys enjoy them - they really are nice little units. i have five or six at work to monitor life testing of our product (a variable speed electric motor), and one at home for general messing around with /ubbthreads/images/graemlins/grin.gif

Mike

 

[jtice]

Mike,

Actually, I think there is $1200 software there !!!!!!! /ubbthreads/images/graemlins/ooo.gif

But, ah, even 256 samples a second is more than enough for me. /ubbthreads/images/graemlins/smile.gif

Yea, I think the USB will work out alot better, alot more plug and play.
Plus the 8 channels will make it really useful. Heck, you could do TWO lights at once. /ubbthreads/images/graemlins/smile.gif

I just need to figure out how to setup each part, IE, how to make it measure mA etc, I hear its not too bad, just add something in line with it, and it will read mA instead of V.

I will have it logging to text files mainly, I think, so I can import them into my own Excel Chart Template I made.

~John

 

[MikeLip]

You can pretty much empty your bank account of all that nasty money on a data aquisition system, that's for sure /ubbthreads/images/graemlins/grin.gif You will need a current shunt of some kind, the lower the value the better. 0.1 ohms might be a place to start, depending on anticipated currents. Even that might eat into your lights' output too much, but you do have to develop enough voltage for the A/D to sort out. You may be able to find those at Radio Shack, but more likely you will have to go to a real electronics parts jobber like Digikey to get them. It might be a good thing for a group buy, since Digikey has a minimum purchase price of $25 - below that you get hit with a $5 handling charge.

Have fun.

Mike

 

[jtice]

thanks for the info Mike,

I have a couple ppl I talk to that should be able to tell me what I need to get, to get it to read the different values.
Voltage is simple, just hook it up /ubbthreads/images/graemlins/smile.gif
Lux, is easy, just hook up the light meater that has analog output, mine says 1mV = 1 Lux /ubbthreads/images/graemlins/smile.gif Simple enough.
The mA is the harder part, have to add something in line with it, I have heard a couple different ways of doing this already. hehe

~John

 

[jtice]

Got this logger last night http://www.dataq.com/products/startkit/di148.htm

Seems pretty nice, but theres gonna be a good bit of setup time.

It measures the battery voltage fine, its accurate for that.
But, its not very accurate at all with my light meter.
The light meter puts out 1mV = 1 Lux, and the logger cant get enough accuracy from such a low signal.

I am told I need to make and attactch an opamp to that channel.
Which, from what I understand, just boosts the signal to a higher level.

The software that comes with it, wont let you import in real time to excel /ubbthreads/images/graemlins/frown.gif
It will however save a csv (excel file) from the data, after you have logged it.
Then I had to manually copy and paste it into my excel page.

The manuals are not very helpful, theres not much in them at all.
I cant figure out what half the software things are lol

Also, its data entries that it saving to excel are in soem sorta scientific format /ubbthreads/images/graemlins/frown.gif
And excels not wanting to format it right /ubbthreads/images/graemlins/frown.gif

 

[pbarrette]

Hi jtice,

Can't you make an excel macro to import and convert the data into your existing template?

If not, I'm sure a script based text editor like sed or possibly a short perl script could convert the data format in the csv and then you could use the excel macro to import and plot.

pb

 

[lymph]

jtice, I have the DI-194RS model and it works fine. If you have any specific questions, let me know and I might be able to help. I primarily use it in linux without the fancy software it came with, but I have played with the windows software a bit. There are also instructions on the website for using ActiveX controls to have it acquire directly into excel.

 

[mrme]

Wow. I want one of those. I don't have 55 buck to spare, but maybe soon.

I never thought these things would be within my budget, but aparently I was wrong!

So is there any way to rig these to measure AC current, hopefully passively. I knew somone who had an ancient looking clamp on current measurment device that would hook into any volt meter. Would there be an easier/cheaper way?