Using Multimeter as current sensor - can it output to Arduino?

Community General Discussions
1

Hi All,

I'm in need of a current sensor, but don't want to wait 40 days to get it shipped from China, or want to pay over 10 times as much buying it locally.

I have an old cheapo multimeter lying around, and I just opened it to see if it had a current sensor IC in it.  It didn't, and now that i've put it back together, the conductive rubbery strips that press against the LCD are misaligned and the display shows me gibberish.

Anyhow, is there a way to have the arduino's analog pins "tap" into a certain area of the multimeter's circuit board, and read the current?  I'd would of course connect the red and black multimeter leads to into a circuit that i wanted to know the current of.

If this isn't possible, does anyone know of any consumer electronics that have current sensors in them?   Or any other type of circuit that can be homemade with easy to find ICs?

And also, if anyone could throw in their "2 cents" about various current sensors and their sensitivity, that would be good.  Here's a list of the sensors that I've come across so far:

Attopilot, 90A max, 37 mV/A sensitivity

ACS758, 50A-150A depending on model, 40 mV/A sensitivity

ACS712, 5A-30A depending on model, 185 mV/A sensitivity

2

Hi Duane,You led me in the

Hi Duane,

You led me in the right direction and I found this page that looks like it goes through the process of using the Arduino directly and measuring across a resistor.  Thanks!

I just want to measure, and record on a computer, the current consumed by each motor of a differential drive robot over a period of time.  I then want to tweak the power consumption curve visually, play it back, and then have the computer send pwm values to the motor controller and have the robot perform the behaviour of the new power curve.

I’ll be using the (animation) software Blender.  I haven’t set it up yet, but after seeing that it can be used to manipulate real-world servos using a wired USB cable, it don’t think it’ll be too much of a stretch to have it move a real-world motor, and then use a wireless serial connection instead of a wired one.

So now i’m just figuring out where to place the resistor, in the 12V RC robot/car circuit, so that i can measure a point directly with an Analog pin.

 

3

Thanks 6677, i’m rummaging

Thanks 6677, i’m rummaging through my junk drawer because i’m sure i have an op amp somewhere.

4

Ok after really thinking

Ok after really thinking about what i’m trying to do here, it looks like there is one other option other than sensing and recording current over time.  And that is sensing and recording the PWM that is being sent to the motor drivers, over time!

 

 

5

Check this link

https://www.robotshop.com/letsmakerobots/current-sensing

It sounds like the circuit will do what you are after.