MKR IMU shield power consumption

Using Arduino Project Guidance
1

Hey all,

I am trying to achieve the lowest possible sleep current with a MKR wifi1010 + mkr IMU shield. The goal is to take a measurement every 10s.

Stand alone MKR wifi1010
By using the code below, with the 'on' led desoldered and battery powered (3.7V) i achieved a sleep current of 1mA.

// Include libraries
#include <WiFi101.h>
#include <ArduinoLowPower.h>

void setup() {
  // put your setup code here, to run once:
  WiFi.end();
}

void loop() {
  // put your main code here, to run repeatedly:
  LowPower.deepSleep(10000);
}

MKR wifi1010 + IMU shield
Now when i attach the MKR IMU shield this sleep current increases to 10mA, which i did not expect, since the deepSleep function should disable everything except the RTC peripherals.

DeepSleep Function
"Puts the MCU in deep sleep mode. The deep sleep mode allows power optimization with the slowest wake-up time. All but the RTC peripherals are stopped. The CPU can be wakeup only using RTC or wakeup on interrupt capable pins."

Question
Is this behaviour expected according to the IMU shield datasheet provided below? If so, is there a way to reduce the power consumption of the IMU shield in sleep mode?

image
image1516×587 68.8 KB

Thanks in advance!

2

Fully normal.

3

Could you explain your answer? I would like to learn :smiley:
Is it because the IMU shield has its own seperate 32-bit microcontroller?

So a solution to reduce the sleep current would be to use a standalone accelerometer like this? Grove - 3-Axis Digital Accelerometer (LIS3DHTR) | Kiwi Electronics

Thanks for taking your time to answer, really appreciated

4

Remove the LED on the shield (or the current limiting resistor). The expected current draw of the BNO055 is given in the BNO055 data sheet.

The goal is to take a measurement every 10s.

What sort(s) of measurement?

5

I forgot to mention, but i already had removed the LED on the shield.

I went for a stand alone acceleration sensor, which works perfectly.