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Topic: power usage reduction (Read 1 time) previous topic - next topic

merlijn

Hello

At this moment I'm trying to reduce power usage of an Arduino mini 5

I have used an example schetch from this website http://www.gammon.com.au/forum/?id=11497

And this sample Schetch from this website


+++++++++++++++++++++++++++++++++++++++++++++++++++++++
#include <avr/sleep.h>

void setup ()
{
  set_sleep_mode (SLEEP_MODE_PWR_DOWN); 
  sleep_enable();
  sleep_cpu (); 
}  // end of setup

void loop () { }
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

but the power usage from the arduino mini does not goes below the 3,3 Ma
Has anybody a hint for me
or is it not possible with this board to go below the 3,3 ma
on the site where I found this sample was a bare bone used for this experiment
but as far as I Know are there on the mini except for the power led not that much power consumers

already thanks in advance

Merlijn

Paul__B

If you look at the article you cite, it explains that the reason you cannot reduce the power usage further is that the Mini or Pro Mini has an on-board regulator with a quiescent current draw of a certain number of milliamps.  And a "power" LED.

If you want to go lower, you need to assemble your own board in some way - as the article explains - and do without a regulator - generally by using a 4.5V battery.

merlijn

Hello Paul thanks for  jour input

This morning I looked in the schematic drawing of the Ardino mini board
and found out that the power led has a supply voltage of 5 v and a resistor of 1K ohm in serie
so maximum current could be 5 Ma
I checked that by doing a current measurement parallel over the power led
and measured 4,8 ma
I also measured the voltage drop over the led in normal use and that is 1,8 v
so I can make the following calculation ( correct me if I'm wrong )
the voltage over the resistor = 5v supply voltage minus 1,8 voltage drop over the led  = 3,2 v
so the current used by the power led = 3,2v / 1k ohm = 3,2 ma

is this conclusion correct ????
if so I will have to remove the led to reduce the current usage or buy a other board
like a pro mini which has a resistor from 10k Ohm before the power led

I hope someone can acknowledge my conclusions

Kind regards
and thanks in advance

Merlijn


nickgammon

That sounds right. Of course anything that generates light is going to consume quite a bit of current. As my article explains, if you must have a power LED, just pulse it for 5 milliseconds or so (per second or two) to reduce the average consumption.
Please post technical questions on the forum, not by personal message. Thanks!

More info: http://www.gammon.com.au/electronics

fungus


... the current used by the power led = 3,2v / 1k ohm = 3,2 ma

is this conclusion correct ????


It's about what I'd expect for a power LED.


if so I will have to remove the led to reduce the current usage


Yes.


or buy a other board like a pro mini which has a resistor from 10k Ohm before the power led


If you remove the built-in LED you could easily add another with whatever resistor you want.

OTOH you'll never achieve microamp power consumption with any sort of constantly-lit LED.

Advanced Arduino

merlijn

Hello

I Think that my thoughts are confirmed by the previous replies
and I think I have to remove the power led witch can not  unfortunately disabled by a jumper or so

Thanks everybody for your help it was very useful for me

kind regards

Merlijn

fungus


Hello

I Think that my thoughts are confirmed by the previous replies
and I think I have to remove the power led witch can not  unfortunately disabled by a jumper or so


On the Pro Mini people often cut a PCB track as shown here:



There might be an equivalent on your board. Have a look at the schematic.
Advanced Arduino

Paul__B




On the Pro Mini people often cut a PCB track as shown here:


[/quote]

If Tim Giles happens to be on line, that is.  :D


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