UNO power consumption 2x of Duemilanove while sleeping (higher all around)

Projects General Guidance
1

Hello Everyone,

I have a project that's power sensitive, not uA sensitive, but I want to get it low with sleeping. I'm using the really nice Narcoleptic library to make it sleep. Also using a WiShield...not my favorite, but it works. I was mocking everything up but decided to test the power draw of just the arduino/shield. W/a Duemilanove during a sleep, the arduino w/just the shield, no external circuitry at all, draws just shy of 20mA. If I use the same exact code and the same exact WiShield on an UNO, It's drawing 48mA while sleeping. While doing something useful w/the shield it's about 103mA vs 140mA. Is this just the new USB sucking that up? I'll certainly plan to use Duem. in this project, but any advice on getting the UNO down for the next one that roles around?

Thanks.

2

Yes it is the USB to serial bridge that accounts for the difference.

3

Well, that and the +5V and +3.3V regulators.

If your final project does not need USB interface, can build up a standalone board & trim parts out.

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4

My mini pro draws 1.6ma when sleeping and still have a Sparkfun Serial LCD still powered. I hope to get it below 0.1ma.

Your USB chip will draw power as will the voltage regulator.

5

Hi All,

Thanks for the info! Forgot about that 3.3 now having it's own regulator as well...yep, that'll do it.

A mini pro being down at 1.6mA, that's awesome. I like the full size board for my project but it sounds like the pro is the way to go if you're looking to get the power down. Seems it's time to invest.

Thanks again.

6

I should point out that was putting power direct into Vcc not RAW so it bypasses the voltage regulator. I also disabled the power LED.

By doing this, using the correct sleep mode and powering any external components only when awake you should be able to achieve much lower power consumption. The processor alone should get as low as 1uA ( or is it 0.1uA) in sleep mode. Thats at least 1/1000 of what I get now.