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    • E

      Solid blue LED after deep sleep
      FiPy • pytrack deep sleep battery powered pytrack battery deepsleep wake • • Edward Dimmack  

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    • D

      Expansion board 3.1 : Powering off LiPo
      Expansion Board • expansion board battery powered boot • • DomGiles  

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      robert-hh

      @pac_71 No. A Pull-Up resistor connected between P8 and 3.3 V dose not require extra action. At a value of 4.7k or 10k, some other units, the ESP32 or a logic output of an external device, can drive it low when needed. No switch is required. P8 is also used for the SD card. So connecting it directly to 3.3V would block the SD card.
    • B

      PySense hardware versions 1.0 vs 1.1 with Lopy - battery lifetime issue
      Discussion • lopy pysense deep sleep battery powered • • b3da  

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    • T

      FiPy + Pytrack power consumption
      FiPy • fipy pytrack power battery powered pytrack battery • • Turbolego  

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      jmarcelino

      Hi @turbolego Power consumption will vary with usage, you can find all the details on the datasheet: https://docs.pycom.io/chapter/datasheets/downloads/fipy-specsheet.pdf
    • joearkay

      LoPy + NPN Transistor + Ratiometric Sensor
      LoPy • sensor battery powered transistor npn ratiometric • • joearkay  

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      joearkay

      @robert-hh - Further to this - I actually haven't got the sensor to hand (awaiting shipment), but once it arrives, I'll measure the current draw at 3V3 to confirm that the datasheet is accurate.
    • J

      LoRa NVRAM clear on restore issues
      Discussion • lora lorawan deep sleep battery powered nvram • • jcaron  

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      G

      @jcaron Thanks. Just to note this method works also for both a software reset AND powercycle.
    • M

      Powering the LoPy with 2 AA batteries?
      LoPy • lopy battery power battery powered • • mahe  

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      J

      @robert-hh Things are much better now it's wired correctly! :-) The batteries and the converter have been at room temperature for the last few hours and my LoPy and sensor are working fine. Thanks again for your help Robert.
    • ledbelly2142

      LoPy with Expansion board, How do you measure LiPo Battery up to 4.2V?
      LoPy • lopy battery battery powered battery monitor • • ledbelly2142  

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      ledbelly2142

      @jmarcelino Once again, thanks for the great feedback. I was looking for a simple way to alert when the battery needs to be recharged. Looks like some simple logic could be: if voltages gets to 3.3, alert for recharge... So many LiPo batteries have differing characteristics, even among the same model/make/capacity/manufacturer. I don't think there is real value is tracking a percentage... without extensive battery testing. Simplest thing to do is just report voltage. From the example from HERE do you recommend using the following: numADCreadings = const(100) def ADCloopMeanStdDev(): adc = machine.ADC(0) adcread = adc.channel(attn=1, pin='P16') samplesADC = [0.0]*numADCreadings; meanADC = 0.0 i = 0 while (i < numADCreadings): adcint = adcread() samplesADC[i] = adcint meanADC += adcint i += 1 meanADC /= numADCreadings varianceADC = 0.0 for adcint in samplesADC: varianceADC += (adcint - meanADC)**2 varianceADC /= (numADCreadings - 1) print("%u ADC readings :\n%s" %(numADCreadings, str(samplesADC))) print("Mean of ADC readings (0-1023) = %15.13f" % meanADC) print("Mean of ADC readings (0-1400 mV) = %15.13f" % (meanADC*1400/1024)) print("Variance of ADC readings = %15.13f" % varianceADC) print("10**6*Variance/(Mean**2) of ADC readings = %15.13f" % ((varianceADC*10**6)//(meanADC**2))) print("ADC reading for Voltage (0-1400 mV) = %15.4f" % (meanADC*1400/1024)) From the ACD pin 16 voltage, the voltage is the meanACD*1400/1024 Does not seem right, the output is 4966.3634.
    • R

      Is the time in the RTC preserved after hard reset w/o power down?
      LoPy • lopy rtc battery powered • • rolandvs  

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      bmarkus

      @rolandvs said in Is the time in the RTC preserved after hard reset w/o power down?: If true it makes the use of the RTC sort of worthless in situations where you want to keep time with an attached battery without the possibility to use Wi-Fi to NTP your time like with LoPy or SiPy... It doesn't solve the original issue, but you can update time without network connection using GPS receiver, e.g. on the pytrack extension board.
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