For a while, I've been wanting to see how much DC current my various Arduino projects use. Each time I go looking for an ammeter, I see a bunch of options and decide it's not important.
But, the curiosity is getting too hard to put aside. For my usage - detecting DC current used for an Arduino project (or LED strip, etc), what type would you recommend?
I don't need scary good accuracy. I'd mainly like to have a device where I can quickly hook up and determine the current draw.
Perhaps I'm really in the market for two: A low current in-line one that I can hot-melt glue onto a breadboard, and then a higher current one for detecting current usage for LED strips.
A decent multimeter can measure DC current from microamperes to 20 amperes or so, on various ranges. A multimeter is an excellent general purpose tool that you will use all the time.
Keep in mind that there is a fuse inside the case which is easy to blow (and change) if you make the wrong connection while using the current ranges.
There is very rarely a reason to build a meter into your project.
I do have a Greenlee multimeter that I like, but unfortunately, it doesn't have ammeter functionality. Would you still recommend the route of a multimeter? Or since I have one already, does it make more sense to go with something specific to current?
Just about any multimeter should work, but check it's low-current range because some meters may not have much resolution at 10 or 20mA, etc.
Current measurements are relatively rare (compared to voltage & resistance measurements) because you have to break the circuit and insert the meter. And in most situations you can calculate or estimate the current.
At work I do have a benchtop power supply with voltage & current meters built-in. That's handy.
If you are trying to measure power consumption then a handheld multimeter isn't the right tool. Most projects will be turning things on and off so fast that you can't measure them by just looking at the multimeter readout. Something that turns a relay on and off will have widely different power consumption when the relay is on or off. Even if it switches slowly enough for you to write down the two different currents, then you have to estimate what percent of the time it is using that much current.
An Arduino and a hall-effect current sensor can be used much more effectively for this kind of measurement. Take 1000 readings every second and then add up the total. Display that on your screen. Multiply by the measured voltage to get watts. Show peak current and minimum current.
But that's a project I always wanted to build myself. That might not be what you need or desire. If you have zero current measurement tools right now, then a multimeter is a good place to start.
MorganS:
If you are trying to measure power consumption then a handheld multimeter isn't the right tool.
Yes, it depends on what exactly you wish to measure. A multimeter will measure more or less the average value of the current. For many purposes that is adequate. If you want to know the peak values you will need to use a shunt and an oscilloscope.