ADC + BEACON + BATTERY LIFE

[SHUBHAM]

I am working on RTLS project. In beacon i am advertising battery life and temperature along with minor number and RSSI . I am merging battery strength and temperature in major ID . i did every thing successfully but the problem is with ADC for which i am using poling method is taking lots of battery power. For beacon i am using 3.3. v battery with 650 mAH current drop. H ow can i increase my battery life with ADC n advertising for beacon. What calculation should i follow for nrf52832 soc.

[Jørgen Holmefjord]

Hi,

When the SAADC peripheral in nRF52832 is enabled, the current consumption will increase due to EasyDMA being active. To decrease the current consumption, you need to disable the SAADC peripheral between sampling. If you only measure battery voltage, you should not need a high sample rate.

A low power SAADC example for SDK 11 is available in this GitHub repository. In SDK 12 and 13, there is a low power mode in the driver. It can be activated by setting SAADC_CONFIG_LP_MODE in sdk_config.h.

The current consumption of the SAADC peripheral:

• I_(ADC,CONV) (ADC current during ACQuisition and CONVersion): 700 µA

• EasyDMA current: ~1.5 mA

Best regards,

Jørgen

[SHUBHAM]

Thanks a lot for your prompt response
one more thing is that i am using poling method to update advertising packet along with power_manage() function. Is this method is OK or should i use something else.

[Jørgen Holmefjord]

What do you mean by "poling method"? In general, the recommended way to do this is to use RTC/app_timer to trigger the sample task and update the advertising data at a given interval. This is shown in the example I linked above.

[SHUBHAM]

yes you are write bot i'm calling fun. nrf_drv_saadc_sample(); in a LOOP.

[Jørgen Holmefjord]

That does not sound like a good idea with regards to current consumption, but if you could provide code snippet of your current solution I could help you improve it.

[SHUBHAM]

yes that's why i am thinking of using RTC with ADC. for nrf52 is there any example code to show saadc with RTC.