Is there a multimeter (volts, ohms, amps) for under $250 that can easily be hooked to a computer and output it's measurements to Excel or even a text file? I need something like that for a world domination work project.

-Blast

Offhand, I can't point you to a specific product. But my understanding is that you can have a full-featured pc-based-oscilloscope in that price range. As for multimeters, it's important to specify what you are trying to track -- most importantly, if it's sine wave, the frequency range and the sampling frequency that will give you meaningful results. Cheapo units have very specific limitations.

My 2c.

http://www.multimeterwarehouse.com/m9803rf.htm

http://www.multimeterwarehouse.com/MS8226f.htm

http://www.multimeterwarehouse.com/VA18Bf.htm

I've never done business with multimeterwarehouse.com and I have no experience with any of these.

A couple of quick questions about your plans for world domination er ah work.

Portable (i.e. battery powered) or will AC powered work?
How long is each data collection run (many meters have annoying auto off feature) ?
What sort of Voltage etc. ranges / accuracy are you looking for?
Does this thing need to be calibrated for your plans for world domination?
Does the interface matter to you (RS 232 vs USB)?


I used to play with things like this and you can get something just barely usable (i.e. near junk but kind of works) for pretty cheap. $'s increase as reliability, accuracy and ease of use improve. Generally I would try to con the pointy haired bosses into at least a Fluke multi-meter but that would exceed your budget.

pseudo mandatory disclaimer - nothing to do with Fluke, just like their toys.

- Eric

USB or RS232c port?

Here's one for $50 if you want to use RS232C

http://www.multimeterwarehouse.com/MAS343f.htm

The Interface software can be downloaded here;

http://www.nostek.co.kr/software/mas343_345_m9803r.zip

I have downloaded and run the setup.exe and it has an Excel button on the GUI to export the data as an export CSV file.

You could always get a USB to RS232c adapter if your PC doesn't have RS232c port.

or a USB model for $250

http://www.multimeterwarehouse.com/VA38f.htm

Fluke will have USB bench multimeters with USB connectivity but will be more expensive.

Thanks everyone! The current (ha ha ha, I crack myself up!) use would be recording the change in resistance a piece of conductive foam as it undergoes compression. This is a very cheap pressure sensor based on the resistance of the foams dropping as it is compressed. This is coupled with a cheese press to make my own crush-test instrument. High sensitivity/accuracy would be good. These tests would be under five minutes.

If the multimeter works well with the computer I foresee using it as the basis for all sorts of jury-rigged sensors. Towards that end a USB connection would be nice and easy. The ability to hook a thermocouple to the multimeter would make is useful for a bunch of different tests. In the past I've used LabView software and sensors, but my current boss hates them for some reason. Add to that my budget is almost non-existent and I'm left with building equipment out of scraps and garage-sale finds. But in the end I SHALL RULE THE WOR... er, hopefully get a promotion at work.

-Blast

How about a Cheap,Digital Postal Scale,You'd be able to Accurately Measure the psi or gsm,thus the Resistance!

Why do I get flashbacks to episodes of Pinky and the Brain whenever Blast subtly introduces us to his real agenda?

Pinky's last question of the day "Brain, what are going to do tomorrow?"

Brain always gave this reply, "The same thing we do every day, we're going to try to take over the world!"

So, Blast, what's your next evil plan?

Radio shack used to have one, IIRC it was something like $89.
Or find someone with a PIC or Basic stamp setup to hook you up with a $5 microcontroller with an ADC

Google "USB Data Acquisition"

These guys look promising:
http://www.dataq.com/data-acquisition-starter-kits/data-acquisition-starter-kits.htm

or

http://www.mccdaq.com/solutions/USB-Data-Acquisition.aspx

We use a bunch of these at work:
http://www.omega.com/ppt/pptsc.asp?ref=OMB-DAQ55&Nav=dasc01

I'd get one that also accepts thermocouple inputs. You'll wonder how you did a lab test without it. Then again, I'm an ice machine engineer.

By the way, you want a "load cell" to measure the press force.
http://www.omega.com/toc_asp/subsectionSC.asp?subsection=F03&book=Pressure

Standard disclaimer.

You might want to consider a more dedicated data acquisition setup like those mentioned above but I'm not sure how you would get started for under your $250 price point without putting in some time in developing input circuits and figuring out how to process the results. Ultimately a low end USB data acquisition system will be much more flexible since it will provide you with at least 4 input channels (typically +/- 10 V) vs. the one to two channels on a DMM. If you are interested I'll dig around some info I have a work.

Sticking with the multimeter approach you should be able to find a capable setup for under your price point. I don't have any direct experience with any of the brands in this price range but I think Greenlee would be a good place to start since they offer calibrated units in addition to standard units. It looks like the DM-510 or 210 would meet your needs and leave you enough to buy the USB adapter kit.

There are a lot of other brands out there, including some found on the multimeter warehouse links others have referenced. After scanning through these and checking out some other web sources it looks to me like this is a good example of you get what you pay for. Several of these meters look like (and the manuals read very similar to) meters offered by more well known (or maybe just more expensive) brands. Reviews for these meters indicate that when they work, they work well enough but there seem to be occasional quality or performance issues.

Best advice is stick to brands/stores you are comfortable with or those that are recommended by people you know and trust. Realistically that means my recommendation above is suspect since I have never used GreenLee products .

I have no affiliation with any of these brands beyond being a regular user calibrated meters and equipment used in testing critical systems.

Good luck,

-Eric

Tom, that's exactly the system we have hooked up to other equipment. Unfotunately, the tech-wiz who set it all up died in a motorcycle crash several months ago. While my boss tapped me to be the new tech-wiz, he doesn't want me to waste time learning how to set up the Omega systems, he just wants me to do cheap plug-and-play stuff. On the plus side, I may talk him into getting the huge Lego Mindstorm robotics kit for that reason.

-Blast

p.s. If this actually works, some day buildings and bridges will be built out of Blastcrete rather than concrete.

Thanks everyone. The purchase order has been for this one:
http://www.multimeterwarehouse.com/VA18Bf.htm

-Blast

Thought you might like to see the multimeter in action.

FlexTester by merriwether, on Flickr
Stress crack testing using a cheese press, conductive foam, and a multimeter hooked to a computer.
I wanted to write "Front Towards Enemy" on it but figured the people at work already think I'm nuts.

-Blast

Cool set up Blast.

Very neat set-up Blast, looks like interesting testing. Mike

There is nothing quite like a mad scientist's lab.

But you really should have lightning rods on the roof.

It's alive. IT'S ALIVE!