pyTrack2 - sleep and power usage

  • I can't work out how to get low power use when using a lopy4 and pytrack V2 board. I have looked at other posts on this subject (there seems to be many) but have not been able to get current usage when sleeping in the 20uA range. Best I can get is more in the 6mA which will drain batteries too fast. This post was the most useful how-to-deep-sleep-with-sipy-pysense-3-7v-lipo but was for a pysense board and didn't get power usage below about 6mA for me. The GPS on the pyTrack may be further complicating things?

    I've tried a bunch of other approaches i.e setting. gps_state() , using machine.deepsleep() , different settings for go_to_sleep(). Nothing seems to stop high power usage on the pyTrack board when sleeping other than turning of I2C, but then the board can't be restored from a sleep.

    This is the power usage trends I see with the code shown below. (Each 100mv = 40mA - I measured across a 2.5ohm resistor)

    I am trying to use the pyTrack and Lopy4 wake up and take a GPS reading every hour then sleep in low power. I'm getting to the point where I am thinking it might be easier just to add a timed power supply that wakes up evey 1 hour (but I shouldn't need to do that).

    Any hints or pointers to where someone has run a pyTrack in the 20uA range when asleep would be a big help, I am thinking there is something I need to turn off that I haven't done.

    My test code (pytrackHelper.getGPS() gets a gps reading)

    import pycom
    import machine
    import pytrackHelper
    from pytrack import Pytrack
    from LIS2HH12 import LIS2HH12
    from network import WLAN
    import time
    # from network import WLAN
    py = Pytrack()
    acc = LIS2HH12()
    wlan = WLAN()
    # Don't want default blue LED flashes
    # Don't use wifi for my IOT so turn it off to save power
    # Turn off accelerometer
    py.setup_int_wake_up(True, False)
    # py.sd_power(False)
    pytrackHelper.blink(1, 0x00f0f0)
    print("get GPS:", pytrackHelper.getGPS(py, 3))
    pytrackHelper.blink(1, 0xff8f00)  # dark orange
    # Turn off GPS power
    pytrackHelper.blink(1, 0x00ff00)  # Green

  • You have to send the GPS into sleep as well. Have a look into the GPs manual for the matching PMTK sentenes.

    But be warned. The L76 doesn't like to play. Mine has not found any sat for months. I like o have a full erase like the one for the ESP32.

  • One more clue? When I look at the current usage and expand the timebase when in sleep (and awake) I see this square wave pattern with a duty cycle a little over 50ms. Maybe this can help identify the component still drawing power during sleep?


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