src/python/test_tools/power_sweep.py

   1 # This script runs an automated voltage sweep while collecting ADC DBGLN() output
   2 # from an ExpressLRS RX using devAnalogVbat. The receiver should be compiled with:
   3 #   -DDEBUG_VBAT_ADC -DDEBUG_LOG -DDEBUG_CRSF_NO_OUTPUT -DRCVR_UART_BAUD=460800
   4 # (lots of UART errors at the default 420000)
   5 # If firmware is workign correctly `cat /dev/ttyUSB0` will show values such as
   6 #   $ADC,925
   7 #   $ADC,924
   8 #   $ADC,926
   9 #   ...
  10
  11 # Uses the KoradSerial library for power supply control, just dump this in the library directory
  12 # https://github.com/starforgelabs/py-korad-serial
  13 from koradserial import KoradSerial
  14 import time
  15 import serial
  16 import argparse
  17
  18 class MedianAvg:
  19     def __init__(self):
  20         self.reset()
  21     def reset(self):
  22         self.vals = []
  23         self.min = 0
  24         self.max = 0
  25         self.mean = 0
  26     def add(self, val):
  27         self.vals.append(val)
  28     def calc(self):
  29         if len(self.vals) < 3:
  30             self.reset()
  31             return
  32         self.vals.sort()
  33         self.min = self.vals[0]
  34         self.max = self.vals[-1]
  35         self.mean = 0
  36         for i in range(1, len(self.vals)-1):
  37             self.mean += self.vals[i]
  38         self.mean = self.mean / (len(self.vals)-2)
  39     def __len__(self):
  40         return len(self.vals)
  41     def __str__(self):
  42         return f'n={len(self.vals)} mean={self.mean} min={self.min} max={self.max}'
  43
  44 def flushSerial(ser):
  45     while True:
  46         bVal = ser.read_until()
  47         if len(bVal) == 0:
  48             return
  49
  50 def doVoltageSample(ser, voltage):
  51     flushSerial(ser)
  52     adcMedian = MedianAvg()
  53     while True:
  54         sLine = ser.read_until().decode('ascii')
  55         if sLine.startswith('$ADC,') and sLine.endswith('\r\n'):
  56             try:
  57                 iADC = int(sLine[5:-2])
  58                 #print(iADC)
  59                 adcMedian.add(iADC)
  60                 if len(adcMedian) >= 10:
  61                     adcMedian.calc()
  62                     print(f'{voltage:0.1f},{adcMedian.mean:0.4f},{adcMedian.min},{adcMedian.max}')
  63                     adcMedian.reset()
  64                     return
  65             except ValueError:
  66                 pass
  67
  68 def runSweep(args):
  69     with serial.Serial(args.rport, baudrate=args.rbaud, timeout=0.010) as rcvr:
  70         with KoradSerial(args.kport) as pwr:
  71             try:
  72                 #print("Model: ", pwr.model)
  73                 pwrch = pwr.channels[0]
  74                 pwrch.voltage = 5.00
  75                 pwr.output.on()
  76
  77                 print('voltage,mean,min,max')
  78                 for v in range(args.start, args.end+args.step, args.step):
  79                     voltage = v / 100.0
  80                     pwrch.voltage = voltage
  81                     time.sleep(0.2)
  82                     doVoltageSample(rcvr, voltage)
  83             finally:
  84                 pwr.output.off()
  85
  86 if __name__ == '__main__':
  87     parser = argparse.ArgumentParser(
  88         description="Run a voltage sweep using a Korad power supply and recevie ADC data from an ELRS receiver")
  89     parser.add_argument("-b", "--rbaud", type=int, default=460800,
  90         help="Receiver UART baud")
  91     parser.add_argument("-e", "--end", type=int, default=100,
  92         help="Ending voltage (centidegrees 500 = 5.00V)")
  93     parser.add_argument("-k", "--kport", type=str, default='/dev/ttyACM0',
  94         help="Port used for Korad power supply UART")
  95     parser.add_argument("-r", "--rport", type=str, default='/dev/ttyUSB0',
  96         help="Port used for receiver UART")
  97     parser.add_argument("-s", "--start", type=int, default=3100,
  98         help="Starting voltage (centidegrees 500 = 5.00V)")
  99     parser.add_argument("-t", "--step", type=int, default=-10,
 100         help="Voltage step (centidegrees -10 = -0.10V)")
 101
 102     args = parser.parse_args()
 103
 104     runSweep(args)
 105