How to get sub 1mA sleep current on Arduino MKR 1500

Projects General Guidance
1

Hi there,

For a project of mine I am trying to get an as low as possible sleep current on the Arduino MKR 1500.
But I have only been able to get down to 1.1mA by using the following code:

#include <MKRNB.h>
#include <ArduinoLowPower.h>
NB modem;

void setup(){
    delay(500);
    modem.shutdown();
}

void loop(){
    LowPower.sleep(300000);
}

I measured the current by placing a multimeter between a Lipoly battery and the battery connector on the Arduino.

Does anyone know how to get a lower sleep current?

2

It may not be possible to get much lower. The MCU chip itself may be capable of very low sleep current, but the rest of the MKR board may not have been designed with low sleep currents in mind, and nothing you can do in the code can fix that.

Have you heard of anyone getting MKR 1500 below 1.1mA?

3

No, I have not heard of anyone getting the Arduino MKR 1500 below 1.1mA.
But i have seen other MKR boards getting into the uA range.
As far as I know all the modules on the board (like the MCU, modem and crypto chip) have sleep modes and should not consume more than a couple of uA each.

So i do think it is possible to go lower.

4

That sounds hopeful.

I did a quick search and could not find a product page or schematic for the MKR1500. Do you have one?

The problem with integrated development boards is you can't easily measure where all that current is going!

5

The product page for the Arduino MKR 1500 gives me a 404 error. The getting started page is available, but i don't think the schematics are on there.
The getting started page: https://www.arduino.cc/en/Guide/MKRNB1500

I believe the schematics of the Arduino MKR1010 are very similiar to the MKR1500 (besides the modem):

6

Schematics for the MKR NB 1500 (and all other Arduino boards) are available on the "Documentation" tab of the product page:

7

Did you have any luck with this? Trying the same thing, but ~0.5 mA by using the same approach as you.
I also question of the Deep Sleep in the ArduinoLowPower class is suited for MKR 1500 or just older cards.