VL53L0x save power

[zhy]

Hi，

   vl53L0x goto sleep and wakeup to reduce power.

  I used single_mode,program as follow:

   I find add 

         sensor_init(dev,vl53_mode);            //activa

  The measurement time was 600 mS. long more than not add  this function？

  how  to reduce the time?

[zhy]

  used sleep wakeup  or not used sleep wakeup

[Zhiyuan.Han · Accepted solution]

Hi 

As long as you don't power off the sensor, and only let sensor go into sleep mode, there is no need to call the initiation function. 

Initialization will take long time as it includes many registers settings inside. 

Br

Zhiyuan.Han

[zhy]

When performing two measurements per second, how can the power consumption of the VL53L0x be reduced? Is a single measurement or continuous timed measurements preferable? I adopted continuous timed high-speed measurements, setting the measurement duration to 22 ms with a 900 ms interval between measurements, resulting in an average measured current of 19 mA (according to the specification). Based on this, I calculated the average power consumption.
(22 mS × 19 mA + 5 μA × 878 mS) / 900 mS = 0.4693 mA. I don't understand why others can achieve 20 μA.

[Zhiyuan.Han]

Hi 

You choice "continuous timed" mode is the correct mode. and you power consumption calculation method is absolutely correct. Normally the power consumption is mainly consumed during ranging window.  

To reduce the power further, you can try to decrease the ranging time(Timing budge ) and increase the idle time(InterMeasurmentPeriod). 

Br

Zhiyuan.Han

[zhy]

Hi dear Han

   you say decrease the ranging time, What is the minimum value? 

During each interrupt, does the hardware ensure that the measured value remains below the threshold?

  thanks

[Zhiyuan.Han]

Hi 

About the minimum ranging time, this totally depends on your use case, if the test target reflectance is high enough, you can decrease the timing budget further, and if you use case don't need long distance detection, you can decrease the timing budget. 

Overall, there is no fixed minimum timing budget value for reference.  you can try to decrease timing budget step by step to make sure the sensor is still working fine for your use case. 

Br

Zhiyuan.Han

[zhy]

Hi，

I employ continuous timed interrupts, triggering when the distance falls below 1 meter. Measurements are accurate in dark conditions, but under strong lighting, the interrupt trigger interval becomes significantly shorter; I measure once per second.

[zhy]

Reducing the signalLimit value will cause false triggers, whereas increasing it to 0.80×65536 ensures the interrupt is triggered only when the distance falls below 0.8 meters in bright light conditions.

[Zhiyuan.Han]

Hi

When TOF working under such condition, the ToF emitted signal is not changed, but the ambient noise increased, this causes the system SNR decrease, with ambient noise increase, the system SNR can't guarantee the stable measurement, that's why you will see the false target or false interrupt trig. 

ST ToF is not designed for outdoor/strong ambient noise use case.

Br

Zhiyuan.Han