Can't connect to nRF cloud when UI Module disabled (Asset Tracker, Thingy 91)

[andrew926]

Hello,

I want to measure current consumption of nRF9160 of the Thingy 91 with the Asset Tracker application in PSM mode without GPS. For that, I added to the function modem_configure in main.c the lines

int err = 0;

#if defined(CONFIG_LTE_POWER_SAVING_MODE)
		err = lte_lc_psm_req(true);
		if (err) {
			LOG_ERR("PSM request failed, error: %d", err);
			return err;
		}

		LOG_INF("PSM mode requested");
#endif

I also changed data sending interval to 300 s and disabled LEDs, buzzer and NMOS in prj_thingy91_nrf9160ns.conf:

CONFIG_ENVIRONMENT_DATA_SEND_INTERVAL=300
CONFIG_LIGHT_SENSOR_DATA_SEND_INTERVAL=300
CONFIG_HOLD_TIME_RSRP=300

CONFIG_UI_LED_USE_PWM=n
CONFIG_UI_BUZZER=n
CONFIG_UI_NMOS=n

I tested it in LTE Link Monitor and PSM was successfully activated with my desired TAU (00100001 = 1 hour). I did not enable eDRX.

After that I disabled logging by editing the prj_thingy91_nrf9160ns.conf:

CONFIG_LOG=n
CONFIG_SERIAL=n
CONFIG_LOG_IMMEDIATE=n
CONFIG_USE_AT_HOST=n

And I added to the spm.conf:

CONFIG_SERIAL=n

I tested the application and it worked fine. The Thingy 91 was sending sensor data to the nRF Cloud every 300 s (5 minutes).

Then I measured the current consumption with an advanced digital multimeter (Keysight 34465A) and got an average current consumption of 6.5 mA, which is way more than I expected.

I decided to turn off the UI module in prj_thingy91_nrf9160ns.conf:

CONFIG_USE_UI_MODULE=n

After this, I can't connect to the nRF Cloud. Nothing happens when I turn on the Thingy 91 and wait for 15 minutes. I tried it several times and reopened the nRF Cloud.

Any ideas why the application doesn't work with disabled UI module? And what can I do to reduce power consumption of the asset tracker application?

I use ncs version 1.4.0 and modem firmware version 1.2.2.

[Hakon]

Hello,

you can try removing the entire src/ui folder from asset tracker, and rebuild.

[andrew926]

Thank you for the advice! I removed src/ui folder and commented out following symbols in prj_thingy91_nrf9160ns.conf:

#CONFIG_UI_LED_USE_PWM=n
#CONFIG_UI_BUZZER=n
#CONFIG_UI_NMOS=n
#CONFIG_USE_UI_MODULE=n
#CONFIG_NRF_CLOUD_LOG_LEVEL_DBG=y
#CONFIG_NRF9160_GPS_LOG_LEVEL_DBG=n
#CONFIG_CONSOLE_GETCHAR=y
#CONFIG_AWS_FOTA_LOG_LEVEL_DBG=y
#CONFIG_AWS_JOBS_LOG_LEVEL_DBG=y

and changed:

CONFIG_CONSOLE_SUBSYS=n
CONFIG_CONSOLE_HANDLER=n

In Kconfig, I commented out

#rsource "src/ui/Kconfig"

In CMakeLists.txt I commented out

...
#  src/ui
...
#add_subdirectory(src/ui)

Then I commented out every '# include "ui.h" ' and 'ui_led_set_color(...)' and 'ui_led_set_pattern' call in main.c and gps_controller.c. 

I tested the application and it connects! 

Then I added 'set_gps_enable(true);' in the end of the main() function, because the Asset Tracker application does not react to button presses when UI module is disabled. Unfortunately, GPS still doesn't work. What can I do to make GPS work with UI module disabled?

Then I measured the current consumption (without 'set_gps_enable(true);'), and it is about the same as before, too high. How can I lower the current consumption of the Asset Tracker application? It has peaks of 40 mA every 180 ms. Could you measure the current consumption of the Asset Tracker application, to see what I mean, and to compare? Here is the link to my project: https://yadi.sk/d/WooH3vjoHxBHuA .

[Hakon]

andrew926 said:

It has peaks of 40 mA every 180 ms.

How long do these peaks last? Can you post a plot?

[andrew926]

First 12 seconds (y unit Ampere, x unit seconds):

Zoomed in between seconds 8 and 9:

The duration of a 40-50 mA peak is about 0,02 seconds. What could it be and how can I turn it off? As far as I know, the sensors do not consume so much power. There is also 1 mA current consumption in between the 40-50 mA peaks, which is much. Where could it come from?

This current was measured with Keysight 34465A before I removed src/ui. I also measured the current with a cheap multimeter at home.

The results of the cheap multimeter measurements were the same after I removed src/ui. I haven't measured the current with Keysight 34465A after I removed src/ui because at the moment I don't have access to it.

[andrew926]

I did the plot with 3000 measurements per second and got an average current (calculated by multimeter) of 6.5 mA.