power usage reduction

Other Hardware 3rd Party Boards
1

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 Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors

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

2

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.

3

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

4

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.

5

merlijn:
... 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.

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

Yes.

merlijn:
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.

6

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

7

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

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.

8

fungus:

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


[/quote]

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