Deep sleep mode with nrf52840

[Judge]

hi everyone, I am having a problem making the door sensor. I want to optimize the power of the sensor so after acting I will put the sensor in system_off mode. I have the following problem:
1, Can I wake up the sensor using a timer? If possible, how to use it?
2, Before sensor sleep deeply I want to use the friend node to store sensor data. So anyone has an example of this problem?

[Simonr]

Hi

1. When the nRF is in system_OFF mode, the only ways to wake it up will be to either trigger a reset or to use the Low power comparator (LPCOMP) to trigger a wake-up. You won't be able to use any internal timer or sensor to trigger this reset, as the CPU is turned off, but an external sensor should be able to trigger a reset on the nRF, which will wake it up from system OFF mode.

2. I assume you're referring to the friend node functionality in the Bluetooth Mesh specification here? You can check out the Mesh SDK documentation over on the Infocenter, and specifically the "Integrating Low Power node feature" to see how you can handle and set up friend nodes.

Best regards,

Simon

[Judge]

hi,

thanks for answer Simonr, 

But

I tried using lpn but I had problems setting up friendship. I have read in inforcenter, do I know when setting up the friendship app I will have to call mesh_lpn_friend_accept () before timeout but I don't understand how it will send?