I have a attached a rotary encoder to a DC motor shaft in hopes of creating a python script on a PI4 in which one could set a desired angle, motor will move CW at a 10 - duty cycle, and motor will stop and hold position on desired angle that once set angle is read back into code from rotary encoder (# 800 pulses per revolution - reading out 0.45 deg increments).
The PI controller will ideally then hold the set angle (set in code but later GUI) and will not move regardless of outside force on the shaft.
Lastly i am using if statments after my PI control signal 'PI' into a duty cycle ouput thus controlling the speed of the motor as it reaches the set point (either slowing down or speeding up tp get to the set point) with error PI polarity governing directional output....if this could be done better i'd appreciate any suggestions
I am only getting 1 error i cant figure out and cant find a solution online...but i feel i am close to getting this code right. Any criticism is welcome. The error is regarding the "PI" output of the Pi equation:
"Value of type "int" is not indexable"
from RPi import GPIO
import time
import threading
#Encoder GPIO Pins
clk = 15 # GRN/YLW Z+
dt = 11 # BLU/GRN Z-
GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)
GPIO.setup(clk, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
GPIO.setup(dt, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
#Motor GPIO Pins
PWMPin = 18 # PWM Pin connected to ENA.
Motor1 = 16 # Connected to Input 1.
Motor2 = 18 # Connected to Input 2.
GPIO.setup(PWMPin, GPIO.OUT) # We have set our pin mode to output
GPIO.setup(Motor1, GPIO.OUT)
GPIO.setup(Motor2, GPIO.OUT)
GPIO.output(Motor1, GPIO.LOW)# When program start then all Pins will be LOW.
GPIO.output(Motor2, GPIO.LOW)
def MotorClockwise():
GPIO.output(Motor1, GPIO.LOW) # Motor will move in clockwise direction.
GPIO.output(Motor2, GPIO.HIGH)
def MotorAntiClockwise():
GPIO.output(Motor1, GPIO.HIGH) # Motor will move in anti-clockwise direction.
GPIO.output(Motor2, GPIO.LOW)
#Sim Values
duty_c = 10 #duty Cycle
PwmValue = GPIO.PWM(PWMPin, 10000) # We have set our PWM frequency to 5000.
PwmValue.start(duty_c) # That's the maximum value 100 %.
error = 0
Set_point = 1.8
encoder_counter = 0
encoder_angle = 0
Kp = 2
Ki = 1
PI = 0
#Sim Parameters
Ts = .1 #sampling time
Tstop = 200 #end simulation time
N = int(Tstop/Ts)#simulation length
def ReadEncoder():
global encoder_counter
global encoder_angle
clkLastState = GPIO.input(clk)
while True:
clkState = GPIO.input(clk)
dtState = GPIO.input(dt)
encoder_angle = float(encoder_counter/800)*360
if clkState != clkLastState:
if dtState != clkState:
encoder_counter += 1
else:
encoder_counter -= 1
#print("encoder_counter", encoder_counter )
print("encoder_angle", encoder_angle )
time.sleep(1)
clkState = clkLastState
# some delay needed in order to prevent too much CPU load,
# however this will limit the max rotation speed detected
time.sleep(.001)
def PI_function():
global PI
global duty_c
global error
global Kp
global Ki
global encoder_angle
for k in range(N+1):
error = int(Set_point) - encoder_angle
print (f"{error} Error Detected")
PI = PI[k-1] + Kp*(error[k] - error[k-1]) + (Kp/Ki)*error[k] #PI equation
print (f"{PI} PI value")
if (PI > 0):
MotorClockwise()
else:
MotorAntiClockwise()
if ((PI > duty_c) & (duty_c <100)):
duty_c += 1
if ((PI < duty_c) & (duty_c > 10)):
duty_c -= 1
return()
def main_function():
if (N != 0):
encoder_thread = threading.Thread( target=ReadEncoder)
encoder_thread.start()
encoder_thread.join()
PI_thread = threading.Thread( target=PI_function)
PI_thread.start()
PI_thread.join()
PwmValue.ChangeDutyCycle(duty_c)
else:
PwmValue.ChangeDutyCycle(0)
print(f"Motor Stopped & Holding at {encoder_angle} Degrees")
I'm working on automation of a vision based machine driven by stepper motor. Structure of my program is as followed.
import ImageProcessing
import Mechanices
import cv2
def rotate_motor(steps,direction):
global g_motor_ploc
DIR = 20 # Direction GPIO Pin
STEP = 21 # Step GPIO Pin
delay = .00055
GPIO.setmode(GPIO.BCM)
GPIO.setup(DIR, GPIO.OUT)
GPIO.setup(STEP, GPIO.OUT)
GPIO.output(DIR, direction)
for x in range(steps):
GPIO.output(STEP, GPIO.HIGH)
sleep(delay)
GPIO.output(STEP, GPIO.LOW)
sleep(delay)
GPIO.cleanup()
def findImage():
####################################
< Very Fast Image Processing Code >
####################################
return position_of_object
def calculate_steps(position):
####################################
< Very Fast Steps and Direction Calculation Code >
####################################
return steps_required,direction_of_rotation
def main():
while True:
position=findImage()
steps, direction = calculate_steps
rotate_motor(steps,directions) # Very Slow Process
if __name__ == "__main__":
main()
Despite very fast processing of images, whole program has to wait for rotate_motor to complete before processing next frame. In mean time if object moves backward it fails to see the change unless previously calculated position is achieved.
I'm looking forward to run rotate_motor in a separate thread and update the number_of_steps and direction required for motion. So that even if previously calculated position is not achieved, it should know how many more steps are required or change of direction is required.
So I modified the program as followed:
import multiprocessing as mp
import cv2
(r, g_w) = mp.Pipe(True)
g_motor_ploc = 0
def rotate_motor(steps,direction):
global g_motor_ploc
DIR = 20 # Direction GPIO Pin
STEP = 21 # Step GPIO Pin
delay = .00055
GPIO.setmode(GPIO.BCM)
GPIO.setup(DIR, GPIO.OUT)
GPIO.setup(STEP, GPIO.OUT)
GPIO.output(DIR, direction)
for x in range(steps):
GPIO.output(STEP, GPIO.HIGH)
sleep(delay)
GPIO.output(STEP, GPIO.LOW)
sleep(delay)
if direction==1:
g_motor_ploc -= 1
else:
g_motor_ploc += 1
GPIO.cleanup()
def findImage():
####################################
< Very Fast Image Processing Code >
####################################
return position_of_object
def calculate_steps(position):
####################################
< Very Fast Steps and Direction Calculation Code >
####################################
return steps_required,direction_of_rotation ## (Clockwise, Counter Clockwise)
def linear_motion(r):
global g_motor_ploc
while True:
loc = r.recv()
steps = loc - g_motor_ploc
if steps < 0:
direction = 1
else:
direction = 0
rotate_motor(abs(steps),direction)
def main():
while True:
position=findImage()
steps = calculate_steps
g_w.send(steps)
if __name__ == "__main__":
motor_proc = mp.Process(target=linear_motion, args=(r,))
motor_proc.daemon = True
motor_proc.start()
main()
Using the mp.Pipe() it interrupts the linear_motion() as soon as new position is send to the pipe. However this process if so fast that linear_motion never reach to the rotate_motor part.
Any suggestions, I'm confused.
I'm working on a Raspberry Pi project which displays a different video-loop depending on which of the 3 PIR motion sensors are "sensing motion". When no sensors are sensing anything, I want to display an additional video. So all in all there are 4 videos: left, middle, right, not-active.
Using Python 3.4.2 , I have managed to get videos playing when sensors are activated, but I am having difficulties getting a video to play when none of the sensors are active. I thought it would be a simple 'else' like clause, but apparently it is not. I've tried many different methods, but have ran out of ideas. Can someone help me integrate a "no motion detected" return to the code? The code is as below:
''' Import required stuff '''
import RPi.GPIO as GPIO #GPIO
import time #for delay
import subprocess #for omxplayer
''' GPIO setup '''
GPIO.setmode(GPIO.BCM) #GPIO setmode
PIR_PIN_L = 23 #define left pin
PIR_PIN_R = 24 #define right pin
PIR_PIN_M = 25 #define middle pin
GPIO.setup(PIR_PIN_L, GPIO.IN) #set left pin
GPIO.setup(PIR_PIN_R, GPIO.IN) #set right pin
GPIO.setup(PIR_PIN_M, GPIO.IN) #set middle pin
'''Definitions '''
def MOTIONL(PIR_PIN_L): #define motion on left
print("Motion Detected on Left!") #output if motion detected
def MOTIONR(PIR_PIN_R): #define motion on right
print("Motion Detected on Right!") #output if motion detected
def MOTIONM(PIR_PIN_M): #define motion in middle
print("Motion Detected at Middle!") #output if motion detected
''' Initiation '''
print("PIR Module Test (CTRL+C to exit)")
time.sleep(4)
print("Ready")
''' Sensing '''
try:
GPIO.add_event_detect(PIR_PIN_L, GPIO.RISING, callback=MOTIONL)
GPIO.add_event_detect(PIR_PIN_M, GPIO.RISING, callback=MOTIONM)
GPIO.add_event_detect(PIR_PIN_R, GPIO.RISING, callback=MOTIONR)
while 1:
time.sleep(100)
except KeyboardInterrupt:
print("Quit")
GPIO.cleanup()
I've replaced the video parts with print("Motion detected ...") for simplicity. If you can add a print("No motion detected") when no sensors are activated, it would be very helpful.
I managed to solve the issue, and thought I'll post it in case someone wants to use it. Note that the code has been changed quite considerably. It still uses very low CPU. The only difference is that this code is more efficient at picking up motions, but at the cost of higher false readings. That may be fixed by adjusting the knobs on the PIR sensor. The same concept can be applied to the code above.
''' Import required stuff '''
import RPi.GPIO as GPIO #GPIO
import time #for delay
''' GPIO setup '''
GPIO.setmode(GPIO.BCM) #GPIO setmode
PIR_PIN_L = 23 #define left pin
PIR_PIN_R = 24 #define right pin
PIR_PIN_M = 25 #define middle pin
GPIO.setup(PIR_PIN_L, GPIO.IN) #set left pin
GPIO.setup(PIR_PIN_R, GPIO.IN) #set right pin
GPIO.setup(PIR_PIN_M, GPIO.IN) #set middle pin
'''Definitions '''
def MOTIONL(): #define motion on left
if GPIO.input(PIR_PIN_L)==1 : #trigger condtion left being active
print("Motion Detected on Left") #output
time.sleep(3)
def MOTIONR(): #define motion on right
if GPIO.input(PIR_PIN_R)==1 : #trigger condtion right being active
print("Motion Detected on Right") #output
time.sleep(3)
def MOTIONM(): #define motion in middle
if GPIO.input(PIR_PIN_M)==1 : #trigger condtion middle being active
print("Motion Detected on Middle") #output
time.sleep(3)
def NOMOTION() :
if GPIO.input(PIR_PIN_L)==0 and GPIO.input(PIR_PIN_R)==0 and GPIO.input(PIR_PIN_M)==0 :
#above trigger condition is no sensor being active
print("No Motion Detected") #output
time.sleep(3)
''' Initiation '''
print("PIR Module Test (CTRL+C to exit)")
time.sleep(4)
print("Ready")
''' Sensing '''
try:
while 1: #calls defined functions simulatanously
NOMOTION()
MOTIONR()
MOTIONL()
MOTIONM()
except KeyboardInterrupt: #CTRL and C will reset shell
print("Quit")
GPIO.cleanup()
the print commands can be replaced with whatever function you wish to call.
I want to experiment with the RaspberryPi, but the .py code doesn't work. It gives me a lot of errors.
a space error
indentation error: expected an indented block " global VELUX_STATE, AUTO_mode "
I only copied the code from the official forum, that works for other people.
Link:
http://egrasland.blogspot.fr/2014/01/control-your-velux-roller-shutter-with.html
I copy the code and paste in "sudo nano script.py"
What do I do wrong ?
Furthermore, the code from the official webiopi from RaspberryPi doesn't work either for me. Debug gives error, and the program doesn't start.
Link: https://code.google.com/p/webiopi/wiki/Tutorial_Basis
Thanks for the answers.
The code I used is:
Python server script :
import webiopi import datetime
GPIO = webiopi.GPIO
VELUX_UP = 17 # GPIO pin using BCM numbering VELUX_DOWN = 18 # GPIO pin using BCM numbering VELUX_STOP = 27 # GPIO pin using BCM numbering
VELUX_STATE = 0 # DOWN AUTO_MODE = 1
HOUR_UP = 9 # Turn Velux UP at HOUR_DOWN = 19 # Turn Velux Down at
# setup function is automatically called at WebIOPi startup
def setup(): global VELUX_STATE, AUTO_MODE
# set the GPIO used for VELUX command to output
GPIO.setFunction(VELUX_UP, GPIO.OUT)
GPIO.setFunction(VELUX_DOWN,GPIO.OUT)
# STOP function not used at this time
GPIO.setFunction(VELUX_STOP,GPIO.OUT)
GPIO.digitalWrite(VELUX_STOP, GPIO.LOW)
# retrieve current datetime now = datetime.datetime.now()
if (AUTO_MODE==1):
# test time
if ((now.hour >= HOUR_UP) and (now.hour < HOUR_DOWN)):
GPIO.digitalWrite(VELUX_UP, GPIO.HIGH)
webiopi.sleep(0.2)
GPIO.digitalWrite(VELUX_UP, GPIO.LOW)
VELUX_STATE = 1
else:
GPIO.digitalWrite(VELUX_DOWN, GPIO.HIGH)
webiopi.sleep(0.2)
GPIO.digitalWrite(VELUX_DOWN, GPIO.LOW)
VELUX_STATE = 0
# loop function is repeatedly called by WebIOPi
def loop(): global VELUX_STATE, AUTO_MODE
# retrieve current datetime now = datetime.datetime.now()
if (AUTO_MODE==1):
# toggle VELUX UP all days at the correct time
if ((now.hour == HOUR_UP) and (now.minute == 0) and (VELUX_STATE == 0)):
GPIO.digitalWrite(VELUX_UP, GPIO.HIGH)
webiopi.sleep(0.2)
GPIO.digitalWrite(VELUX_UP, GPIO.LOW)
VELUX_STATE = 1 #UP
# toggle VELUX DOWN all days at the correct time
if ((now.hour == HOUR_DOWN) and (now.minute == 0) and (VELUX_STATE == 1)):
GPIO.digitalWrite(VELUX_DOWN, GPIO.HIGH)
webiopi.sleep(0.2)
GPIO.digitalWrite(VELUX_DOWN, GPIO.LOW)
VELUX_STATE = 0 #DOWN
# gives CPU some time before looping again webiopi.sleep(1)
# destroy function is called at WebIOPi shutdown
def destroy():
GPIO.digitalWrite(VELUX_UP, GPIO.LOW)
GPIO.digitalWrite(VELUX_DOWN, GPIO.LOW)
GPIO.digitalWrite(VELUX_STOP, GPIO.LOW)
#webiopi.macro def getHours():
return "%d;%d" % (HOUR_UP, HOUR_DOWN)
#webiopi.macro def setHours(on, off):
global HOUR_UP, HOUR_DOWN
HOUR_UP = int(on)
HOUR_DOWN = int(off)
return getHours()
#webiopi.macro def getAutoMode():
return "%d" % (AUTO_MODE)
#webiopi.macro def setAutoMode():
global AUTO_MODE
if AUTO_MODE:
AUTO_MODE=0
else:
AUTO_MODE=1
return getAutoMode()
The debug can't I post here because its on my RaspberryPi and the browser is to slow :)
But the first error he give is the dubble spaces by the comment VELUX UP
"HOUR_UP = 9 # Turn Velux UP at"
I solved this but then is it the error
"def setup():
global VELUX_STATE, AUTO_MODE"
Why?
Thanks!
Can someone please tell me how I would modify this code to come on more than once a day? I am very new to python and trying to get my pi to run this timer. I tried adding an additional variable to the array such as SatOn2 but it is ignored. Clearly I do not understand how this works in Python. This was originally intended to run xmas lights but I am modifying to run an irrigation drip timer.
Any help greatly appreciated. Thank You!
# Raspberry Pi custom Christmas light timer
# import GPIO module
import RPi.GPIO as GPIO
# set up GPIO pins as outputs
# This convention is for the "P1" header pin convention
# where the pins start with P1 in the upper left
# and go to P26 in the lower right, with odds in the
# left column and evens in the right column.
# So, pins P1-11 and P1-12 correspond to GPIO17 and
# GPIO18 respectively.
GPIO.setmode(GPIO.BOARD)
GPIO.setup(11, GPIO.OUT)
GPIO.setup(12, GPIO.OUT)
# import date and time modules
import datetime
import time
# Enter the times you want the lights to turn on and off for
# each day of the week. Default is for lights to turn on at
# 5:30pm and off at 10:30pm on weekdays, on at 5:00pm and off
# at 11:30pm on weekends. Note that this is using a 24-hour clock.
MonOn = datetime.time(hour=17,minute=30,second=0)
MonOff = datetime.time(hour=22,minute=30,second=0)
TueOn = datetime.time(hour=17,minute=30,second=0)
TueOff = datetime.time(hour=22,minute=30,second=0)
WedOn = datetime.time(hour=17,minute=30,second=0)
WedOff = datetime.time(hour=22,minute=30,second=0)
ThuOn = datetime.time(hour=17,minute=30,second=0)
ThuOff = datetime.time(hour=22,minute=30,second=0)
FriOn = datetime.time(hour=17,minute=30,second=0)
FriOff = datetime.time(hour=22,minute=30,second=0)
SatOn = datetime.time(hour=17,minute=0,second=0)
SatOff = datetime.time(hour=23,minute=30,second=0)
SunOn = datetime.time(hour=17,minute=0,second=0)
SunOff = datetime.time(hour=23,minute=30,second=0)
# Store these times in an array for easy access later.
OnTime = [MonOn, TueOn, WedOn, ThuOn, FriOn, SatOn, SunOn]
OffTime = [MonOff, TueOff, WedOff, ThuOff, FriOff, SatOff, SunOff]
# Set a "wait time" in seconds. This ensures that the program pauses
# briefly after it turns the lights on or off. Otherwise, since the
# loop will execute more than once a second, it will try to keep
# turning the lights on when they are already on (or off when they are
# already off.
waitTime = 3
# Start the loop that will run until you stop the program or turn
# off your Raspberry Pi.
while True:
# get the current time in hours, minutes and seconds
currTime = datetime.datetime.now()
# get the current day of the week (0=Monday, 1=Tuesday, 2=Wednesday...)
currDay = datetime.datetime.now().weekday()
#Check to see if it's time to turn the lights on
if (currTime.hour - OnTime[currDay].hour == 0 and
currTime.minute - OnTime[currDay].minute == 0 and
currTime.second - OnTime[currDay].second == 0):
# set the GPIO pin to HIGH, equivalent of
# pressing the ON button on the remote
GPIO.output(11, GPIO.HIGH)
# wait for a very short period of time then set
# the value to LOW, the equivalent of releasing the
# ON button
time.sleep(.5)
GPIO.output(11, GPIO.LOW)
# wait for a few seconds so the loop doesn't come
# back through and press the "on" button again
# while the lights ae already on
time.sleep(waitTime)
#check to see if it's time to turn the lights off
elif (currTime.hour - OffTime[currDay].hour == 0 and
currTime.minute - OffTime[currDay].minute == 0 and
currTime.second - OffTime[currDay].second == 0):
# set the GPIO pin to HIGH, equivalent of
# pressing the OFF button on the remote
GPIO.output(12, GPIO.HIGH)
# wait for a very short period of time then set
# the value to LOW, the equivalent of releasing the
# OFF button
time.sleep(.5)
GPIO.output(12, GPIO.LOW)
# wait for a few seconds so the loop doesn't come
# back through and press the "off" button again
# while the lights ae already off
time.sleep(waitTime)
Something like this should work:
# Raspberry Pi custom Christmas light timer
# import GPIO module
import RPi.GPIO as GPIO
# set up GPIO pins as outputs
# This convention is for the "P1" header pin convention
# where the pins start with P1 in the upper left
# and go to P26 in the lower right, with odds in the
# left column and evens in the right column.
# So, pins P1-11 and P1-12 correspond to GPIO17 and
# GPIO18 respectively.
GPIO.setmode(GPIO.BOARD)
GPIO.setup(11, GPIO.OUT)
GPIO.setup(12, GPIO.OUT)
# import date and time modules
import datetime
import time
# Enter the times you want the lights to turn on and off for
# each day of the week. Default is for lights to turn on at
# 5:30pm and off at 10:30pm on weekdays, on at 5:00pm and off
# at 11:30pm on weekends. Note that this is using a 24-hour clock.
MonOn = datetime.time(hour=17,minute=30,second=0)
MonOff = datetime.time(hour=22,minute=30,second=0)
TueOn = datetime.time(hour=17,minute=30,second=0)
TueOff = datetime.time(hour=22,minute=30,second=0)
WedOn = datetime.time(hour=17,minute=30,second=0)
WedOff = datetime.time(hour=22,minute=30,second=0)
ThuOn = datetime.time(hour=17,minute=30,second=0)
ThuOff = datetime.time(hour=22,minute=30,second=0)
FriOn = datetime.time(hour=17,minute=30,second=0)
FriOff = datetime.time(hour=22,minute=30,second=0)
SatOn = datetime.time(hour=17,minute=0,second=0)
SatOff = datetime.time(hour=23,minute=30,second=0)
SunOn = datetime.time(hour=17,minute=0,second=0)
SunOff = datetime.time(hour=23,minute=30,second=0)
MonOnTwo = datetime.time(hour=12,minute=30,second=0)
MonOffTwo = datetime.time(hour=13,minute=30,second=0)
# Store these times in an array for easy access later.
OnTime = [[MonOn, MonOnTwo], [TueOn], [WedOn], [ThuOn], [FriOn], [SatOn], [SunOn]]
OffTime = [[MonOff, MonOffTwo], [TueOff], [WedOff], [ThuOff], [FriOff], [SatOff], [SunOff]]
# Set a "wait time" in seconds. This ensures that the program pauses
# briefly after it turns the lights on or off. Otherwise, since the
# loop will execute more than once a second, it will try to keep
# turning the lights on when they are already on (or off when they are
# already off.
waitTime = 3
halfWait = waitTime / 2
# Start the loop that will run until you stop the program or turn
# off your Raspberry Pi.
while True:
# get the current time in hours, minutes and seconds
currTime = datetime.datetime.now()
# get the current day of the week (0=Monday, 1=Tuesday, 2=Wednesday...)
currDay = datetime.datetime.now().weekday()
for dtimes in OnTime[currDay]:
#Check to see if it's time to turn the lights on
if (currTime.hour - dtimes.hour == 0 and
currTime.minute - dtimes.minute == 0 and
currTime.second - dtimes.second > -halfWait and
currTime.second - dtimes.second < halfWait):
# set the GPIO pin to HIGH, equivalent of
# pressing the ON button on the remote
GPIO.output(11, GPIO.HIGH)
# wait for a very short period of time then set
# the value to LOW, the equivalent of releasing the
# ON button
time.sleep(.5)
GPIO.output(11, GPIO.LOW)
for dtimes in OffTime[currDay]:
#check to see if it's time to turn the lights off
if (currTime.hour - dtimes.hour == 0 and
currTime.minute - dtimes.minute == 0 and
currTime.second - dtimes.second > -halfWait and
currTime.second - dtimes.second < halfWait):
# set the GPIO pin to HIGH, equivalent of
# pressing the OFF button on the remote
GPIO.output(12, GPIO.HIGH)
# wait for a very short period of time then set
# the value to LOW, the equivalent of releasing the
# OFF button
time.sleep(.5)
GPIO.output(12, GPIO.LOW)
# wait for a few seconds because it's pointless to burn energy
# with no benefit
time.sleep(waitTime)