In my low power project, I'm using a Arduino Pro Mini (5V, 16 MHz, ATMEGA328) and a low wattage 3W power supply. Everything else on the system other than the Arduino uses a max of 1.98W.

How much power should I budget for the Arduino Pro Mini (without any mods, ie: disconnecting the voltage regulator and LED)?

  • What voltage is the supply? And you may need a mod or two regardless. And can you get away with a lower voltage for the rest of the project? Sep 10, 2014 at 22:40
  • @IgnacioVazquez-Abrams Its a 5V power supply. I am using a 2.5V and 3.3V regulator to provide the necessary voltages to the other components. What kind of mods would u suggest?
    – Nyxynyx
    Sep 11, 2014 at 2:07
  • Well, for starters I'd look to see if you could use a lower voltage power supply with the same power output. Sep 11, 2014 at 2:10
  • @IgnacioVazquez-Abrams I could use a 3W power supply with 3.3V output rail. Do you think the Arduino can be powered by using a 5V boost regulator?
    – Nyxynyx
    Sep 11, 2014 at 2:46
  • I wouldn't bother. I'd just power it with 3.3V. Set the CKDIV8 fuse and bump up the prescaler if you need a higher clock speed than 2MHz. Sep 11, 2014 at 3:28

1 Answer 1


Arduino mini, and atmega328 in general use less than 10mA with default arduino code. Turning down unused component (ADC and so on), using deep sleep and optimizing pbc would lover this consumption a lot, in the land of uA

  • 1
    That'll be a power consumption of 5V x 10mA = 50mW? The remaining 1W of capacity from the power supply should be sufficient to power the Arduino I guess?
    – Nyxynyx
    Sep 11, 2014 at 9:40
  • Yes, your calculation are right and your watt enough
    – Lesto
    Sep 11, 2014 at 9:41
  • 1
    The onboard "power on" led will increase the power usage by a bit (guesstimated around 5mA). @Nyxynyx note that a 3W rated power brick doesn't always produce 3W reliably. I've had power bricks that dropped their voltage quite a bit when using more that like 75% of their rating.
    – Gerben
    Sep 11, 2014 at 18:03
  • @Gerben Thanks for the warning. I'm considering the following: CUI PBK-3-5 and Recom RAC03-05SC. The specs look decent to me, what do you think?
    – Nyxynyx
    Sep 11, 2014 at 18:22
  • @Nyxynyx Those are absolutely fine. I was talking more of wall-adapters. I found those problems especially in phone chargers (my explanation is; phones don't need exactly 5v to charge their 3.7v battery, so the voltage drop is less of an issue, and makes the charger a few cents cheaper to make).
    – Gerben
    Sep 11, 2014 at 18:30

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