| 1,6 → 1,10 |
|---|
| #!/usr/bin/python |
| |
| # Python library for RPS01A MLAB module with AS5048B I2C Magnetic position sensor. |
| # MLAB meteostation wind speed gauge with magnetic rotation sensor. |
| # This simple algorithm calculate difference between five time equidistant points during the rotation. The result is angular speed per time step. |
| # Size of time-step could be varied depending on expected wind speed range to measure. |
| # Algorithm should be expanded by Kalman filtering to minimize dependence on fast reading. |
| # The measuring principle could introduce time-stamped reading to increase precision of measurement. It could be possible because the readings are not exactly time equidistant in real Linux word. |
| |
| #uncomment for debbug purposes |
| #import logging |
| 9,6 → 13,7 |
|---|
| import time |
| import datetime |
| import sys |
| import numpy as np |
| from pymlab import config |
| |
| #### Script Arguments ############################################### |
| 64,24 → 69,39 |
|---|
| #### Data Logging ################################################### |
| |
| try: |
| angles = np.zeros(5) |
| angles[4] = sensor.get_angle(verify = False) |
| time.sleep(0.01) |
| angles[3] = sensor.get_angle(verify = False) |
| time.sleep(0.01) |
| angles[2] = sensor.get_angle(verify = False) |
| time.sleep(0.01) |
| angles[1] = sensor.get_angle(verify = False) |
| n = 0 |
| speed = 0 |
| AVERAGING = 50 |
| |
| while True: |
| # for i in range(10): |
| angle1 = sensor.get_angle(verify = False) |
| time.sleep(0.1) |
| angle2 = sensor.get_angle(verify = False) |
| time.sleep(0.1) |
| angle3 = sensor.get_angle(verify = False) |
| |
| if (angle1 < angle2): |
| speed = (angle2 - angle1)/0.01 |
| else: |
| speed = (360 - angle1 + angle2)/0.01 |
| for i in range(AVERAGING): |
| time.sleep(0.01) |
| angles[0] = sensor.get_angle(verify = False) |
| |
| |
| |
| sys.stdout.write("Speed: " + str(speed) +"\t"+ str(angle1) +"\t"+ str(angle2) + "\t\tMagnitude: " + str(sensor.get_magnitude()) |
| + "\tAGC Value: " + str(sensor.get_agc_value()) + "\tDiagnostics: " + str(sensor.get_diagnostics()) + "\r\n") |
| sys.stdout.flush() |
| time.sleep(0.01) |
| if (angles[0] + n*360 - angles[1]) > 300: |
| n -= 1 |
| angles[0] = angles[0] + n*360 |
| |
| elif (angles[0] + n*360 - angles[1]) < -300: # compute angular speed in backward direction. |
| n += 1 |
| angles[0] = angles[0] + n*360 |
| |
| else: |
| angles[0] = angles[0] + n*360 |
| |
| speed += (-angles[4] + 8*angles[3] - 8*angles[1] + angles[0])/12 |
| angles = np.roll(angles, 1) |
| |
| speed = speed/AVERAGING # apply averaging on acummulated value. |
| print "Speed: %0.2f \t Total Angle: %0.2f \r\n" % (speed, angles[0]) |
| |
| except KeyboardInterrupt: |
| sys.exit(0) |