Low Power Node example application

[Dinesh]

Hi,

Greetings!

I just tried Low Power Node example application from SDK for mesh 16.0.0

It works functionally well, however I am little curious to know below point(s)

1. Will this type of application survive on CR2032 cion cell?

2. If yes then how long it will go?

Please note that here I am considering no additional hardware resources here.

Regards,

Dinesh

[Mttrinh]

Hi,

With the Friendship feature it enables the Low Power Node to only be in receive mode at scheduled events. It will receive cached messages from a Friend node, which allows the LPN to operate on a coin cell. It is difficult to say exactly how long it will last, it depends on how often the LPN wakes up.

[Dinesh]

Hi Mttrinh,

Greetings!

Thanks for your reply.

I tried Low Power Node example and observed that it consumes around 400uAmp of current (this could be near to actual practical current consumption.) (Checked on Digital Multi-meter, please note that I have not any other device to measure current right now, so please bear with me.)

So instead of debating on how long the battery will last, let's discuss on below point

a. Is 400 uAmp is desired current consumption? or should it be couple of micro-amperes?

b. If it should be too much lesser then what are the possible mistakes, I have been making?

c. If have checked sleep mode current of nRF52832 and it shows 1-2 micro-amperes on digital multi-meter.

d. Correct me if I am going in wrong direction.

Can we not put LPN device in sleep mode? Just in order to have better current consumption.

Thanks in advance.

Regards,

Dinesh

[Dinesh]

Hi

Greetings!

I have some updates after taking some trials

1. As our schematic having only 1 external crystal connected (32MHz), we have defined Softdevice clock configuration to 'NRF_SDH_CLOCK_LF_SRC_SYNTH'

2. With this configuration we were getting around 400 micro-ampere consumption

3. Then we tried with development board to cross-verify, there also we get the same results

4. Next we tried with 'NRF_CLOCK_LF_SRC_XTAL' on development board and we get consumption near around 5 micro-ampere

Here please guide me whether it is right that with 'NRF_SDH_CLOCK_LF_SRC_SYNTH' clock configuration, power consumption gets increased and

with 'NRF_CLOCK_LF_SRC_XTAL' configuration we get better results.

Regards,

Dinesh

[Stian Røed Hafskjold]

Yes, the NRF_SDH_CLOCK_LF_SRC_SYNTH explains the high current consumption you are seeing. It uses the HF clock to synthesize the LF clock. The run current of the HF clock including the internal clock tree is about 400 uA

[Dinesh]

Hi Stian,

Thanks for your reply.

Now I am waiting for our new board which is having 2nd crystal.

We will have trials on those boards and will then conclude on the same.

By the way if LF clock external crystal is connected and clock selection made accordingly then roughly how much current consumed in nRF52832? Is it near around 5 uA?

Thanks in advance.

-Dinesh