Get power value displayed in web interface.

[quky]

Got some led strip lights working using a python script and would like to change the color of it according to the power generated by ORM.
How can I get the power value that is displayed on the web interface from my python script.

[Abasz]

There are a few ways that is possible:

1. You can write a python script wrapper around the ORM nodejs app and parse the console out and take the value
2. You can write a standalone python program that connects to the nodejs webserver and take the power value that ORM broadcasts
3. You can write a standalone python program that connects to ORM via BLE and take the power value from that

[JaapvanEkris]

Or another option is to change ORM to move to a more standalone client that polls a webservice provided by node.js. This way we could provide a standardized interface to the webbased clients, be it a webGUI or a polling script of some kind. I'd be interested in introducing that to the main branch as it opens up new scenario's like integrating into home automation (and perhaps switch to https://github.com/Abasz/ESPRowingMonitor-WebGUI ?)

[Abasz]

I'd be interested in introducing that to the main branch as it opens up new scenario's like integrating into home automation (and perhaps switch to https://github.com/Abasz/ESPRowingMonitor-WebGUI ?)

I will be removing the websocket based connection in favor of a pure BLE interface (with an custom extended metrics UUID).

Or another option is to change ORM to move to a more standalone client that polls a webservice provided by node.js.

Its totally possible, actually not even a big effort on the peripheral side. The only change that is required is that the latest metrics needs to be stored in a variable (or data repository) which gets updated on every data change and before every pull this is quired.

[quky]

well it's looks like it's not as simple as i thought. my programming skills are not at that level to say the least.
appreciate your inputs.
just in case this the python script

import RPi.GPIO as gpio
from time import sleep
import time, math
from datetime import datetime
from rpi_ws281x import *
import argparse

# LED strip configuration:
LED_COUNT      = 95     # Number of LED pixels.
LED_PIN        = 18      # GPIO pin connected to the pixels (18 uses PWM!).
#LED_PIN        = 10      # GPIO pin connected to the pixels (10 uses SPI /dev/spidev0.0).
LED_FREQ_HZ    = 800000  # LED signal frequency in hertz (usually 800khz)
LED_DMA        = 10      # DMA channel to use for generating a signal (try 10)
LED_BRIGHTNESS = 255      # Set to 0 for darkest and 255 for brightest
LED_INVERT     = False   # True to invert the signal (when using NPN transistor level shift)
LED_CHANNEL    = 0       # set to '1' for GPIOs 13, 19, 41, 45 or 53

#process params
dist_meas = 0.00
olddist_meas = 0.00 #last loop
km_per_hour = 0
mph = 0
knots = 0
rpm = 0
elapse = 0
pulse = 0
gust = 0 #last gust
avg = 0 #last average

#your params to set:
sleeptime = .1 #secs between reporting loop
gustint = 3 #secs to calc gust (>sleeptime)
avgint = 3 #secs to trigger average calc (>gustint)
secsnoread = 15 #number of seconds rotor is stationary before a 'no read' is declared and set result to zero - depends on inertia of your rotor in light >no wind
errortime = 60 #number of seconds of no activity before error/stationary warning is shown - set high after debugging
loopcount = 0 #a 'nothing is happening' counter
r_cm = 7.2 #cm wheel radius as parameter (assumed centre of cups)
sensor = 2 #BCM
magnets = 3 #how many magnets in your rotor? (code assumes one sensor though)

#startup numbers
circ_cm = 2 * math.pi * r_cm	    # calculate wheel circumference in CM (1 rotation)
dist_km = circ_cm / 100000 / magnets	    # convert cm to km (rotation/magnets)
start_timer = time.time()           # for interrupt function
gust_timer = time.time() #start of this gust timing
gustm_start= dist_meas #start of this gust distance
avg_timer = time.time() #start of this average timing
avgm_start = dist_meas #start of average distance

def init_GPIO():
    gpio.setmode(gpio.BCM)
    gpio.setwarnings(False)
    gpio.setup(sensor,gpio.IN,gpio.PUD_UP)

def calculate_elapse(channel):                          # callback function
    global pulse, start_timer, elapse
    pulse+=1			    # increase pulse by 1 whenever interrupt occurred
    elapse = time.time() - start_timer	    # elapsed time for a half rotation causing a pulse (edit for maplin sensor 2 magnets)
    start_timer = time.time()		    # let current time equals to start_timer

def calculate_speed():
    global rpm,olddist_meas,dist_meas,km_per_hour
    try:
        rpm = 1 / elapse * 60 / magnets              # 2 interrupts per rotation made 
        km_per_hour = dist_km / elapse * 3600	    # calculate KM/hour 
        dist_meas = dist_km * pulse * 1000    # measure distance traverse in meter
        if dist_meas == olddist_meas:
            km_per_hour = 0
            rpm = 0
        return km_per_hour
    except ZeroDivisionError:
        pass

def init_interrupt():
        gpio.add_event_detect(sensor, gpio.FALLING, callback = calculate_elapse, bouncetime = 20)

# Define functions which animate LEDs in various ways.
def colorWipe(strip, color, wait_ms=50):
    """Wipe color across display a pixel at a time."""
    for i in range(strip.numPixels()):
        strip.setPixelColor(i, color)
        strip.show()
        time.sleep(wait_ms/1000.0)

def theaterChase(strip, color, wait_ms = 50, iterations = 50):
    """Movie theater light style chaser animation."""
    for j in range(iterations):
        for q in range(3):
            for i in range(0, strip.numPixels(), 3):
                strip.setPixelColor(i + q, color)
            strip.show()
            time.sleep(wait_ms / 1000.0)
            for i in range(0, strip.numPixels(), 3):
                strip.setPixelColor(i + q, 0)

def report(mode):
        if mode=='realtime': #comment this mode if you want a quieter report, or use
            mph=km_per_hour/1.609344
            knots=km_per_hour/1.852
        elif mode=='average':
            print(datetime.now().ctime(),'{0:.1f} Gust, {1:.1f} Average (both MPH)'.format(gust/1.609344,avg/1.609344))
        elif mode=='error':
            print(datetime.now().ctime(),'dead calm or connection fault')#report rotor still stationary
        else:
            print('bad report mode')

# Main program logic follows:
if __name__ == '__main__':
    # Process arguments
    parser = argparse.ArgumentParser()
    parser.add_argument('-c', '--clear', action='store_true', help='clear the display on exit')
    args = parser.parse_args()

    # Create NeoPixel object with appropriate configuration.
    strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS, LED_CHANNEL)
    # Intialize the library (must be called once before other functions).
    strip.begin()
    init_GPIO()
    init_interrupt()
    print ('Press Ctrl-C to quit.')
    if not args.clear:
        print('Use "-c" argument to clear LEDs on exit')
    theaterChase(strip, Color(0,255,0))
    
    try:
        while True:
            olddist_meas = dist_meas
            calculate_speed()
            if olddist_meas != dist_meas:
              theaterChase(strip, Color(0,255,0))
              #report('average')
              loopcount = 0
            else:
              loopcount+=1
              if loopcount == 20 / sleeptime: #after each 60 secs,
                 loopcount = secsnoread / sleeptime + 1 #reset loopcount
                 colorWipe(strip, Color(0,0,0), 10)
                 #report('error')
            sleep(sleeptime)
    except KeyboardInterrupt:
        if args.clear:
            print ('Close app.')
            colorWipe(strip, Color(0,0,0), 10)

this is how they look kind of cool. 😃

[Abasz]

So one of the main issue is that this script does not use power but rather considers speed (from distance and time) :)

The other, even bigger issue, is that there is no link between the two application. Basically you count the number of rotations (signals) in your script which is redundant as ORM does the same thing. Which also means that two code may not even work as the GPIO will be already in use (though I am not sure what python uses under the hood, nodejs uses pigpio).

Overall, I think you are on the wrong track. You will need to get the power value as an input in your script from ORM rather than try to calculate things in your script from raw impulses and interrupts.

ORM exposes this figure in several ways: websocket, BLE, ANT+, and even in the console I think.

You need to create an interface in your python script that connects to one of these and take the power value from there.

[JaapvanEkris]

ORM exposes this figure in several ways: websocket, BLE, ANT+, and even in the console I think.

If you accept some delay, you could even capture it from syslog. When logging for the engine is turned on, it will log power. It is a simple commandline with grep and awk to find power.

Websocket would be most elegant in this case.

[quky]

well thanks for the subjections the command line grep awk sed utilities did the trick. don't really care about delay.
here is the python script

import subprocess
import RPi.GPIO as gpio
from time import sleep
import time, math, traceback
from datetime import datetime
from rpi_ws281x import *
import argparse


# LED strip configuration:
LED_COUNT      = 95     # Number of LED pixels.
LED_PIN        = 18      # GPIO pin connected to the pixels (18 uses PWM!).
#LED_PIN        = 10      # GPIO pin connected to the pixels (10 uses SPI /dev/spidev0.0).
LED_FREQ_HZ    = 800000  # LED signal frequency in hertz (usually 800khz)
LED_DMA        = 10      # DMA channel to use for generating a signal (try 10)
LED_BRIGHTNESS = 255      # Set to 0 for darkest and 255 for brightest
LED_INVERT     = False   # True to invert the signal (when using NPN transistor level shift)
LED_CHANNEL    = 0       # set to '1' for GPIOs 13, 19, 41, 45 or 53

sensor = 2 # BCM
rower_power = 0 # rower power from ORM syslog
sleeptime = .3 # secs between loop

def get_power(channel):
   cmd = "grep 'power:' /var/log/syslog | awk '{print $15}'| sed 's/..$//' | tail -n1"
   output = ""
   global rower_power
   test = subprocess.Popen(cmd, stdout = subprocess.PIPE, stderr = subprocess.PIPE, shell = True)
   while True:
       output += test.stdout.readline().decode("utf-8")
       if test.poll() is not None:
          break
   try:
    rower_power = int(output)
    print('get_power', rower_power)
   except ValueError:
      print(f"Error: {data} cannot be converted to an integer.")

def init_GPIO():
    gpio.setmode(gpio.BCM)
    gpio.setwarnings(False)
    gpio.setup(sensor,gpio.IN,gpio.PUD_UP)

def init_interrupt():
        gpio.add_event_detect(sensor, gpio.FALLING, callback = get_power, bouncetime = 20)

# Define functions which animate LEDs in various ways.
def colorWipe(strip, color, wait_ms=50):
    """Wipe color across display a pixel at a time."""
    for i in range(strip.numPixels()):
        strip.setPixelColor(i, color)
        strip.show()
        time.sleep(wait_ms/1000.0)

def theaterChase(strip, color, wait_ms = 50, iterations = 50):
    """Movie theater light style chaser animation."""
    for j in range(iterations):
        for q in range(3):
            for i in range(0, strip.numPixels(), 3):
                strip.setPixelColor(i + q, color)
            strip.show()
            time.sleep(wait_ms / 1000.0)
            for i in range(0, strip.numPixels(), 3):
                strip.setPixelColor(i + q, 0)

# Main program logic follows:
if __name__ == '__main__':
    # Process arguments
    parser = argparse.ArgumentParser()
    parser.add_argument('-c', '--clear', action='store_true', help='clear the display on exit')
    args = parser.parse_args()

    # Create NeoPixel object with appropriate configuration.
    strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS, LED_CHANNEL)
    # Intialize the library (must be called once before other functions).
    strip.begin()
    init_GPIO()
    init_interrupt()
    print ('Press Ctrl-C to quit.')
    if not args.clear:
        print('Use "-c" argument to clear LEDs on exit')

    try:
        while True:
            #print('while true', rower_power)
            if rower_power > 0 and rower_power < 199: #Blue
                  print('Blue', rower_power)
                  theaterChase(strip, Color(0,0,255))
            if rower_power > 200 and rower_power < 299: #Green
                  theaterChase(strip, Color(0,255,0))
            if rower_power > 300 and rower_power < 349: #BRIGHT MAGENTA
                  theaterChase(strip, Color(255,0,255))
            if rower_power > 350: #Red
                  theaterChase(strip, Color(255,0,0))
            if rower_power == 0:
                  colorWipe(strip, Color(0, 0, 0)) #Black
            sleep(sleeptime)
    except KeyboardInterrupt:
        if args.clear:
            print ('Close app.')
            colorWipe(strip, Color(0,0,0), 10)

much appreciated your help.