BLOG 9 : Power Savings with NEXTION DISPLAY

13 Nov 2017

Hey Guys, While working on the Battery decisions in my previous Blog I came across a huge issue of power consumption.

Let's see how - taking into consideration the following

1. Avg Current consumption - ~15mA for the STM32 Nucleo and ~105mA for the Display (Considering 15mA to be insignificant)

2. So with a 3000mAH battery and about 110mA load Running time = 3000/110 * 0.7. == ~19 Hours

3. Now if somehow I can reduce the avg current consumption to half then the runtime will be doubled HeheheHAHAHAHA PPPOOOWWWeeeRRRR !!! (Just wondering how many of you remember Powerpuff girls )

Lets see my solution in detail, On any normal LCD display the maximum power consumption is due to he LED's which contribute to about 85% of power consumption.

Now lets see if we can control the brightness Referring to the Nextion Instruction Set -- dim command dims the display where if we set dim to 0 it will switch off the LED's just perfect moreover thsp & thup can set the display in sleep mode and wake it respectively.

Now in my GUI, The maximum time someone will spend is on the RIDE Screen, but I cannot make it absolutely BLANK / 0 brightness. so I have implemented a Slow dim mechanism wich will smoothly dim the display to a point where the contents are visible and you can get to max brightness just by one tap , The same is also been implemented on Music Controls Screen.

On all other screens I have a timeout there the display enters low power mode, shutting down the LED's as well and one can wake it back up by just a tap.

The implementation and power savings can been seen in below VIDEO

with this instead of ~110mA we will be consuming about ~40 mA if on ride screen for on an Avg that for the given battery I am using will give about ~32 Hours of on Time that gives us additional ~10-12 Hours