adc_battery_again.py

# https://forum.pycom.io/topic/6051/getting-battery-consumption-from-adc

def ADCloopMeanStdDev():
    numADCreadings = const(100)
    adc = machine.ADC(0)
    adcread = adc.channel(attn=3, 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)))