NRF9160 / Asset Tracker V2 / AWS - Power consumption problem with MQTT_KEEPALIVE

[Dev123]

I have an application modified from the Asset Tracker V2. It is on the 1.8 SDK.

I am able to get the power consumption low, but every 20 minutes the application starts the modem and pings AWS. This is because of:

# Maximum specified MQTT keepalive timeout for AWS IoT is 1200 seconds.

#CONFIG_MQTT_KEEPALIVE=1200

The Asset Tracker V2 code does not disconnect from AWS until the modem is shutdown, but in PSM mode- it will not shutdown (and therefore send a shutdown event).

What is the easiest way to stop these connections?

Thanks

[Øyvind]

Hello, 

Could you elaborate more on how you try to disconnect from AWS? Can you use i.e. aws_iot_disconnect?

Kind regards,
Øyvind

[Dev123]

I am using the Asset Tracker V2. It manages connection. My assumption is that it was built for low power. I do not understand how it can be low power if it turns the radio on every twenty minutes. I am assuming I am missing some configuration.

[Øyvind]

Hello, sorry for the late reply. 

What is the power consumption you measured on you device? What exactly is the power consumption problem that you see?

Have you verified that you device is actually in PSM? How often do you want to send data to AWS?

Is there a reason for why you are using nRF Connect SDK v1.8.0? Several improvements have been introduced to our latest version i.e. v2.2.0. 


We will need some more information in order to provide you with an answer.

Thanks!

Kind regards,
Øyvind

[Dev123]

My power consumption is 18 ua when in psm. I have not measured the energy consumption of waking up the radio every twenty minutes, but I know it will be non-trivial on a device meant to last years. Radio is not just turned on, it needs to transmit and it does this 72 times a day.

Peter

[Lorenzo Amicucci]

Hi,
have you considered using Lwm2m or other coap based solutions? 

[Dev123]

In the end, I set it very high and use it as a safety to make sure device talks. So if it is scheduled to talk every 12 hours, I set it to 25 hours to ensure it does not miss. May move it farther out than that.

So now I have a solution for me, but I think a robust sample app for a low power solution should be handling this better (probably disconnecting).

[Øyvind]

Please note that the Asset Tracker v2 is a real-time configurable ultra-low power capable application. This does not mean that it is by default configured to lowest possible configuration. The application is a demonstration of what our nRF9160 is capable of, but will not reflect all use cases.