The best way to save energy in an application

[John12]

Hi,
I am developing an application that includes the following features:
1. PWM to control the buzzer
2. 2 Uarte to communicate with 2 external devices
3. BLE to wireless communication (ble_app_uart)
4. Timer
5. saadc to read battery level
6. nrf_log_info for debugging

Now I want to implement an application as economical as possible, so I planned this topic
1. PWM => I enable/disable depending on when the user wants/don't want to ring buzzer by app_pwm_enable (& context) / app_pwm_disable (& context)
2. Libuarte => I enable/disable uarte when nRF needs/no need to communicate with external devices using nrf_libuarte_async_uninit (& libuarte) / nrf_libuarte_async_ninit (& libuarte)
3. BLE => I increase the advertising interval as big as possible
4. timer => I think app_timer is the best way
5. saadc => now i don't have any solution for this
6. Log Info => I think I will disable it in sdk_config.h => NRF_LOG_BACKEND_RTT_ENABLED 0
I'm using the ON system when the device is idle
So can you give me some comments and suggestions on my plan?
I am using custom board with nRF5833 chip and my application is based on SDK16 ble_app_uart example
As this feature is the most important feature in my project so please provide me a complete process for this feature.
Thank you

[Jared]

1. Using 1V8 should be ok, but note that it sets the VDD_GPIO voltage to 1V8. If you are going to communicate with devices that uses a different voltage range such as 3V3 then you will need a level shifter. 
2. Disabling logging is done by setting NRF_LOG_ENABLED to 0

[John12]

Hi Jared, 
Thanks for your reply. I'll try supply 1.8 and test my application. I have an problem with SAADC and PWM. It quite complicated to use low_power_pwm and low_power_saadc. Because almost time in my application I'm not using them. PWM used for ring the buzzer and SAADC read the battery level per 5 minutes. So I have an idea that use uninit of saadc and pwm by using app_pwm_disable(), nrfx_saadc_uninit() when I use them as shor time when an event trigger and close them almost the time. 
I think It will consume same as low_power_pwm, low_power_saadc

[Jared]

Hi,

What is the problem, are you getting any specific errors? Could you specify them?

regards

Jared

[John12]

Hi, Jared. My custom board still consume a lot of power. With asset tracking device use gps, bluetooth, module sim I only use only 2 days with 700mAH battery. So can you suggest for me another methods like optimizing hardware, firmware or sth. About gps and module sim, It quite simple when I sleep it so I'm sure It consumes little power

[Jared]

Hi,

Is this the same custom board? In your original post you mentioned a nRF52833 based board, asset tracking, gps makes me think that it's a nRF9160 board? Have you done any measurement of the current consumption while it's in sleep?

regards

Jared