PySense hardware versions 1.0 vs 1.1 with Lopy - battery lifetime issue



  • Hi, I'm working on a prototype with Pysense + Lopy + 3xAA batteries as power source.
    When I'm using a Lopy (Firmware 1.17.5.b6) on my Pysense V1.1 (Firmware 0.0.8), the power consumption looks ok and the battery slowly drains.
    If I take the exact same Lopy with no Software changes and put it on a Pysense V1.0 the battery drains much faster.

    I have no idea how this is possible, since there should be no difference between V1 and V1.1!?
    I just want to send temperature + humidity to my gateway and go back to deepsleep.

    Here is my code:
    (there a some useless parts - temp1, temp2, temp3 etc which I am sending over LORA, because if everything is working correctly, I want to send more data. But first I have to find my battery issue)

    from pysense import Pysense
    from SI7006A20 import SI7006A20
    from si7021 import SI7021
    from network import LoRa
    import binascii
    import socket
    import struct
    import machine
    import time
    import pycom
    import utime
    from machine import I2C, Pin
    from machine import WDT
    import uos
    
    wdt = WDT(timeout=60000)  # 60 sec - watchdog
    pycom.heartbeat(False) # turn off heartbeat
    
    _VERSION_SENSOR = 1.14
    
    # A basic package header
    # B: 1 byte for the deviceId
    # B: 1 byte for the pkg size
    # B: 1 byte for the messageId
    # %ds: Formated string for string
    _LORA_PKG_FORMAT = "!BBB%ds"
    _LORA_PKG_ACK_FORMAT = "BBBB"
    _LORA_PKG_LONG_ACK_FORMAT = "BBBBB"
    
    # This device ID, use different device id for each device
    _DEVICE_ID = 0x04
    
    wdt.feed()
    WIFI_MAC = binascii.hexlify(machine.unique_id()).upper()
    
    py = Pysense()
    if (py.read_fw_version() < 8):
        while(True):
            pycom.rgbled(0x001111)
            time.sleep(3)
            print('read_fw_version: '+str(py.read_fw_version()))
            print('uos.uname(): '+str(uos.uname()))
    
    si = SI7006A20(py)
    temp2 = si.temperature()
    hum = si.humidity()
    
    temp3 = 99.99
    voltage = py.read_battery_voltage()
    temp1 = temp2
    pressure = 90000
    lowest = 0
    highest = 0
    
    myMessage = WIFI_MAC+ ';%.2f;%.2f;%.2f;%i;%i;%.0f;%.2f;%.2f' % (temp1, temp2, hum, lowest, highest, pressure, temp3, voltage)
    
    msg_id = 1
    lora = LoRa(
        mode=LoRa.LORA,
        region=LoRa.EU868,
        frequency=868100000,
        power_mode=LoRa.TX_ONLY,
        tx_power=7,
        bandwidth=LoRa.BW_125KHZ,
        sf=9,
        preamble=8,
        coding_rate=LoRa.CODING_4_8, #CODING_4_8
        tx_iq=False,
        rx_iq=False
    )
    lora_sock = socket.socket(socket.AF_LORA, socket.SOCK_RAW)
    lora_sock.setblocking(True)
    pkg = struct.pack(_LORA_PKG_FORMAT % len(myMessage), _DEVICE_ID, len(myMessage), msg_id, myMessage)
    lora_sock.send(pkg)
    
    sleep = 60*15
    
    if (voltage > 1):
        if (voltage < 3.33):
            sleep = 60*60*24
        elif (voltage < 3.4):
            sleep = 60*60
        elif (voltage < 3.5):
            sleep = 60*45
        elif (voltage < 3.55):
            sleep = 60*30
    
    py.setup_sleep(sleep)
    py.go_to_sleep()
    

    Does anybody know, why there could be a difference between V1.0 and V1.1 of the Pysense?
    What could I do, to extend the battery lifetime? If i use sf7 or sf8, my packets are not received reliable.

    Any help is appreciated :)
    Thanks in advance


 

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