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Calculating the average current consumption of a device

rictrajano

Hello,

I'm trying to measure the current consumption of a handheld gaming console and for that I'm using my multimeter. I'm getting values from 0.25mA to 1.5mA depending on if I'm pressing buttons or if sound is being generated. I need to calculate the average but I'm not sure the most efficient way to do it other than let it run let's say for 3 minutes and take an average of all values that the multimeter gave me (quite time consuming since I get a lot of values).

Is there a better way to do it?

Thanks for your help

  • That sounds low, colour me amazed if an LCD runs at that low a consumption level, how have you connected the meter?  You need a logging multimeter or one that can show averages.  Some allow Bluetooth connections to a PC.  You can buy current sense ICs and connect them via I2C to an Arduino.

  • If you're using the multimeter correctly (and as Andrew says, it sounds like very low measurements for typical handheld gaming consoles so that needs to be confirmed), then you're already measuring an average of sorts if you can see the value is (say) mostly 1 mA and you occasionally see it go down to 0.25 mA and sometimes 1.5 mA. 

    I can't see that you'll get a much better measurement than your visual observation of the average, if it fluctuates this much during buttons being pressed or game action, without then formalising what that gameplay is, for instance, if this is a work project then perhaps a test mode could exercise the processor as expected for a typical game, to let you take a measurement, or you'd have to define a typical game.

  • Those are pretty low currents to start with , possibly put a series shunt in the circuit ( a low ohm resistor to not interere with the measurement) and read the resistor voltage drop on a scope. The voltage is in essence current feedback, the scope can chart peaks and calculated averages. The is how the the DVM is measuring current. You could also trigger the scope based on what buttons you're pushing. A 1 or 10 ohm precision resistor shouldnt effect volts too much at those low mA levels.   

  • A typical DMM probably won't measure your device's current accurately in your use case and won't take a meaningful average without some external circuitry. There are many ways to obtain the information you want, such as with filters, coulomb counters, amp-hour meters, watt-hour meters, data acquisition systems, etc. but before launching into a detailed solution description it would be useful to know how much time, effort and money you are willing to spend on this task.

  • in reply to dougw

    you're quite right they do not have more digits. like my HP3435A   this pic is from UTUBE also notice that you can see 3 zeros ie .001