Best DMM for Arduino/BS2/Pic/Blinky Lights type projects

[boulderjoe]

Hey all- I play with arduinos, bs2, blink LEDs, sensors, you know those type of projects.

For that type of work, what kind of DMM would you suggest? With a budget up to $150 what would you suggest?

Thanks!
-Joe

[thilo]

With that budget definitely a (used) Fluke 87 (V). Or alternatively two meters from the $50 shootout.

[IanB]

$150 is a lot to spend if you don't have professional or industrial needs.

For home hobby use on low energy circuits something in the $50 range should be fine. Since it often helps to have two meters on hand, two $50 (or less) meters would likely be more useful than a single $100 meter.

With cheaper meters you may find the readings are out by about 0.03 V in 10 (say 0.3%), but for most purposes this won't be a big issue.

The cheaper meters often have adjustment pots inside that you can use to tweak the calibration and do better than the rough and ready factory setting, whereas the more expensive meters tend to have "closed case calibration" and you'd better hope the factory settings are good or it will cost you $200 to have a professional calibration done.

Fluke meters are nice, but I've never been truly able to say a Fluke would serve me better than the various other inexpensive meters I own.

[ModemHead]

For home hobby use on low energy circuits something in the $50 range should be fine. Since it often helps to have two meters on hand, two $50 (or less) meters would likely be more useful than a single $100 meter.

This is very good advice.

[Uncle Vernon]

The cheaper meters often have adjustment pots inside that you can use to tweak the calibration and do better than the rough and ready factory setting

How? We are talking newbies here, those with neither the expertice, comparison instruments or suitable reference sources. Tweaking pots in those circumstances may result in getting the reading people would like to see, but when undertaken in a random manner would seldom be better than a hit and miss factory calibration.

An experienced hobbyist could readily achieve better results by calibrating against a better and more expensive instrument he has subsequently purchased, and there's the rub.

I'd agree $150 is a healthy budget for such basic needs. Looking for a better than basic instrument can be considered an investment. While  bargains can be had 2nd hand again you have to know what you are buying and who you are buying it from. Purchasing a $50+ new instrument (Extech, Uni-T etc) would be the OPs safest bet.

[IanB]

How? We are talking newbies here, those with neither the expertice, comparison instruments or suitable reference sources. Tweaking pots in those circumstances mayresult in getting the reading people would like to see, but when undertaken in a random manner would seldom be better than a hit and miss factory calibration.

This is true. What I said shouldn't be taken as a recommendation for beginners, more of a future potential that may be possible down the line once some experience has been gained. Definitely don't go in and adjust calibration pots if you are not confident in what you are doing. You could throw the meter way off and have no way to get it back again.

[ivan747]

Like some people suggested, get two $50 multimeters and get a soldering iron. Start by slowly getting things you need until you end up with all of this:



by the time you get and need all that I am sure you will have become quite experienced in the hobby.

By the way, I see you live in Boulder. It's worth to meet this guys and visit their office. They also offer great classes and Arduino stuff:
http://www.sparkfun.com/

[EEVblog]

I agree, with this budget I'd get two meters, very handy.
You could even get a new $50 cheapie (EX-330, AM-220, Uni-T etc) and an old Fluke is you shop around.
A Fluke 25 or 27 is an excellent 2nd hand meter for example.
Or an early model 80 series, like an 83.

Dave.

[Uncle Vernon]

a future potential that may be possible down the line once some experience has been gained.

I hear what you are saying and agree it's true that equipment in this sector probably offers the most scope for optimisation. While the bargain basement junk meters should be written off to experience and sent to the back of the closet it often the case the better equipment often suffers the same fate. While I'llalways recommend the name brands, I'll clarify that you DON'T HAVE TO HAVE A FLUKE for every task. Two meter within that budget is a good idea, I'd also suggest two different meters would be worth considering each with different strenghts and weaknesses.

Definitely don't go in and adjust calibration pots if you are not confidentcompetent in what you are doing. You could throw the meter way off and have no way to get it back again.

We agree. The potential to optimise will still be there at a later date when skill/knowledge levels are sufficient to carry out such tasks.

[Uncle Vernon]

A Fluke 25 or 27 is an excellent 2nd hand meter for example.
Or an early model 80 series, like an 83.

There are lots of 2nd hand bargains to be had of the internet and lots of duds.  I don't see the second hand route being a wise choice for a first instrument though, particularly if it will blow an entire newbie budget on an unknown and untested quantity.  With a budget device from a known brand you have some degree of quality control (albeit likely minimal).
I'd suggest avoiding ebay etc, until the user first has at least a basic reference on hand. 

[ejeffrey]

One thing with test equipment is that you can never have too much, particularly for bread-and-butter things like DMMs, power supplies, and oscilloscopes.  As long as you get something that isn't total junk you are going to continue to use it even if you later pick up a fancier model.

If I were on a $150 budget, I would probably buy a $50 meter and save the rest.  Then after I see what things I love and hate about it, buy a second meter that fixes those problems.  I don't see any realistic scenario where a hobbyist working on low-voltage equipment wouldn't want a $50 meter in addition to whatever other gear.  Unless of course you are Dave, and T&M vendors send you crates of high-end meters such that your fluke 87 is your backup, backup meter.

[olsenn]

I know this probably isn't an opinion that many will aggree with, but personally, I think an oscilloscope is a better first tool than a multimeter (and you'll need to spend at least $400 for a scope). The reason I say this, is because for your blinking lights sort of stuff, knowing precicely what voltage you have isn't very important... a DSO will give you a ball park estimate of what it is (enough to know if it should light or not, be within tolerance for powering an IC etc) and you'll be able to see the frequency operation of your circuit.

The first two things I would buy would be a good 30V 3A power supply with current limiting and a digital readout, then a Rigol scope, a bench multimeter, and finally a waveform generator. A LCR meter also comes in handy. If you need more exotic tools later on like a spectrum analyzer or DC electronic load then you can worry about that when the time comes, but for now, I'd say give up on the $150 budget and getting a multimeter in general, and wait until your budget allows for you to buy decent equipment that will last you a lifetime. Your arduino and little LED projects are a great place to start and you generally won't need a multimeter for those things; and as long as you have a PC, programming can be learned for free.

As for what to spend $150 on... components!!! Lots of components. Get yourself some resistors, capacitors, inductors, op-amps, 555-timers, LED's and bins to store it all in.

[ejeffrey]

I know this probably isn't an opinion that many will aggree with, but personally, I think an oscilloscope is a better first tool than a multimeter (and you'll need to spend at least $400 for a scope). The reason I say this, is because for your blinking lights sort of stuff, knowing precicely what voltage you have isn't very important... a DSO will give you a ball park estimate of what it is (enough to know if it should light or not, be within tolerance for powering an IC etc) and you'll be able to see the frequency operation of your circuit.

I wholeheartedly disagree.  The accuracy is not the important thing.  Even for just measuring voltage, a scope is not a replacement for a DMM.  The DMM is floating, has better ranges at the high and low end, and is simply more convenient to use.  On top of that, a DMM can also measure current, resistance, continuity, capacitance and diode test, and often a few other things like temperature and frequency.  Also, the DMM costs 1/10 the price of a scope.  Scopes are great, don't get me wrong, but there is no way you want to blow $400 on a scope before buying a $50.

[boulderjoe]

Thanks for all of the information. It seems like its hard to go wrong with any of the options.

cheers,
-Joe

[robrenz]

I got one of these free for buying above a certain $ amount.  It agrees very very closely with my calibrated Fluke 8846A on voltage, current, and capacitance ranges.  Continuity is lightening fast and LCD has great contrast. I highly recommend getting two of these.

http://www.circuitspecialists.com/low-cost-multimeter.html

[Harvs]

To get me out of a small problem, being geographically separated from my equipment, I bought one of the $9.95 DMM from Jaycar.

As much as they're cheap, only have +/- 0.5% claimed accuracy, and generally pretty ugly, it's only $10 and pretty much will do all that someone starting out will need.  Apparently they sell them to schools a lot, and they stand up to a fair bit of punishment.

And at the end of the day, it can become a spare to throw in the car emergency tool box when you need something better.

Just a suggestion.

[olsenn]

You're fine; to be honest, you don't even need a multimeter for microcontroller projects like this; when you get to projects that require more strict requirements and/or you just get a higher budget ($10 is a joke) than you can take a look at the offering of Extech and other companies like that

[IanB]

To get me out of a small problem, being geographically separated from my equipment, I bought one of the $9.95 DMM from Jaycar.

Gotta warn you, having bought a few of the $2.95 meters from Harbor Freight Tools, that it might be unreliable when you come to use it. On the HF ones the rotating selection dial develops oxidation problems and the meter reads way off until you spin the dial a few times to clean the contacts.

[Uncle Vernon]

And at the end of the day, it can become a spare to throw in the car emergency tool box when you need something better.

The problem with that is those emergency situationsare the ones where you are likely to be measuring mains wiring or high current vehicle circuits. Those emergencies like getting the lights back on etc. Those situations are also those where you are less likely to be prudent about how you take readings. Equally that spare instrument gets to live in a harsh environment like a tool box in the back of the ute.
Those are just the situations where you are likely to flash a meter or encouter a less than optimal usage environment. Exactly the times when a quality rugged, well protected meter with strong well insulated test leads is going to keep you safe.

I can see where the better cheapo meters might be OK for blinky light stuff, but as a general purpose instrument, ultra cheap meters represent a real health (and wealth) hazard.

[Psi]

Gotta warn you, having bought a few of the $2.95 meters from Harbor Freight Tools, that it might be unreliable when you come to use it

haha, a $2.95 DMM is unreliable.
I never would have guessed

[Harvs]

And at the end of the day, it can become a spare to throw in the car emergency tool box when you need something better.

The problem with that is those emergency situationsare the ones where you are likely to be measuring mains wiring or high current vehicle circuits. Those emergencies like getting the lights back on etc. Those situations are also those where you are less likely to be prudent about how you take readings. Equally that spare instrument gets to live in a harsh environment like a tool box in the back of the ute.
Those are just the situations where you are likely to flash a meter or encouter a less than optimal usage environment. Exactly the times when a quality rugged, well protected meter with strong well insulated test leads is going to keep you safe.

I can see where the better cheapo meters might be OK for blinky light stuff, but as a general purpose instrument, ultra cheap meters represent a real health (and wealth) hazard.

Right... I actually wasn't thinking of that at all.  I just meant auto voltages for when you got problems on the side of the road with lights not working etc.  Basically a substitute for the old test light I use to use when I didn't want to lug a big old analogue meter around the car.  But yes, point taken.

[sonicj]

Right... I actually wasn't thinking of that at all.  I just meant auto voltages for when you got problems on the side of the road with lights not working etc.  Basically a substitute for the old test light I use to use when I didn't want to lug a big old analogue meter around the car.  But yes, point taken.

i think the $2.99 harbor freight meter is a great tool for the glovebox. i would rather have it than a test light if i'm stuck on the side of road playing MacGyver under the dashboard.

i use mine if no other meter is around and i need to quickly check a voltage or resistor value, etc.
-sj

[Uncle Vernon]

i think the $2.99 harbor freight meter is a great tool for the glovebox. i would rather have it than a test light if i'm stuck on the side of road playing MacGyver under the dashboard.

Gotta warn you, having bought a few of the $2.95 meters from Harbor Freight Tools, that it might be unreliable when you come to use it.

Looks like you could be on the side of the road for quite some time.