On 29/01/2021 09:22, Ralph Corderoy wrote:
Hi Peter,
BUT anytime I add anything to the program the subscriber stops firing
the LEDs.
‘Anything’ is very vague. Can you attach the output of
diff -u working.py broken.py
where you've done some simple change which breaks it, e.g...
I can't do that because every time it fails I back it out to the working code.
Attached is the Python with the Logger code inserted. It also contains the
Ultrasonic detection and action [Distance() and us_act()]. Perhaps I don't
know where to find the debug_log.txt.
#!python3
# 2020-09-14 This is a change to RC car-7 from using Flask and HTML to using
Mosquitto
# 2020-11-06 Edited to remove all the calculations leading up to the PWM
percentage
# 2121-01-08 Adding Ultrasonic detection to forward motion, then halt,
reverse, turn left,halt and back to forward
# 2121-01-16 Adding debug statements
# *** SET UP MQTT ***
# from https://techtutorialsx.com/2017/04/23/python-subscribing-to-mqtt-topic/
import paho.mqtt.client as mqtt
import time
import logging
logging.basicConfig(filename='debug_log.txt', level=logging.DEBUG,
format='%(asctime)s - %(levelname)s - %(message)s')
logging.debug('This is a log message.')
Connected = False #global variable for the state of the connection
broker_address= "192.168.4.1"
port = 1883
user = "rc-car-11"
password = "carr0t"
# Create client --?? Is this the same as User?
client = mqtt.Client(client_id="rc-car-11")
# Connect to broker
client.connect(broker_address,1883,60)
# Subscriber to topic
client.subscribe("rc-car-pwm")
# *** SET UP R-Pi GPIO ***
# This gives us control of the Raspberry Pi's pins.
import RPi.GPIO as GPIO
# Tell it which pin number we'll be using to refer to the GPIO pins.
# We will use the physical pin ordering. Set initial state of pins
GPIO.setmode(GPIO.BOARD)
GPIO.setwarnings(False)
MotorFwd = 18
MotorBack = 12
MotorLeft = 19
MotorRight = 23
GPIO.setup(MotorFwd, GPIO.OUT)
GPIO.setup(MotorBack, GPIO.OUT)
GPIO.setup(MotorLeft, GPIO.OUT)
GPIO.setup(MotorRight, GPIO.OUT)
# PWM pin = Motor Forward
u_d_pin_no = 18
GPIO.setup(u_d_pin_no, GPIO.OUT)
# Ultrasonic setup
GPIO_TRIGGER = 13
GPIO_ECHO = 15
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)
frequency_hertz = 50
pwm = GPIO.PWM(u_d_pin_no, frequency_hertz)
PWM_Stop = 0
PWM_value = 0
PWM_increment = 15
# becomes 15 after calculations [old comment]
# set to 15, removed calculations
# can remove duty_cycle_percentage as it is same as PWM_Value
# reverse control Nov 11 2020
# from
https://www.electronicwings.com/raspberry-pi/raspberry-pi-pwm-generation-using-python-and-c
Backpin = 12
GPIO.setup(Backpin,GPIO.OUT) # can remove this as it is MotorBack above
back_pwm = GPIO.PWM(Backpin,1000)
# *** SET UP Functions ***
def on(): # STOP!
global PWM_value
PWM_value = 0
pwm.start(PWM_value)
GPIO.output(MotorBack, GPIO.LOW)
back_pwm.start(0) # added to stop pwm reverse
logger.debug('STOP')
def up_15():
global PWM_value
PWM_value = PWM_value + PWM_increment
pwm.start(PWM_value)
logger.debug('Forward 15, now Distance test')
if distance() < 40:
us_act()
def down_15():
global PWM_value
logger.debug('Slow Down')
if PWM_value > 0 :
PWM_value = PWM_value - PWM_increment
pwm.start(PWM_value)
else :
PWM_value = 0
def motorleft():
GPIO.output(MotorLeft,GPIO.HIGH)
GPIO.output(MotorRight, GPIO.LOW)
logger.debug('Turn Left')
time.sleep(1)
GPIO.output(MotorLeft, GPIO.LOW)
def motorright():
GPIO.output(MotorLeft, GPIO.LOW)
GPIO.output(MotorRight, GPIO.HIGH)
logger.debug('Turn Right')
time.sleep(1)
GPIO.output(MotorRight, GPIO.LOW)
return ()
def mbackwards():
# stop forward motion
global PWM_value
PWM_value = 0
pwm.start(PWM_value)
# wait a short time
time.sleep(0.3)
# now go backwards
# GPIO.output(MotorBack, GPIO.HIGH)
back_pwm.start(30) #30% duty cycle
return ()
def on_message(client, userdata, message):
logger.debug('Wait for button')
if message.payload == b'forward':
up_15()
elif message.payload == b'slow':
down_15()
elif message.payload == b'stop':
on()
elif message.payload == b'motorleft':
motorleft()
elif message.payload == b'motorright':
motorright()
elif message.payload == b'backwards':
mbackwards()
else:
print(message.payload)
def distance():
logger.debug('Start distance sampling')
# set Trigger to HIGH
GPIO.output(GPIO_TRIGGER, True)
# set Trigger after 0.01ms to LOW
time.sleep(0.00001)
GPIO.output(GPIO_TRIGGER, False)
StartTime = time.time()
StopTime = time.time()
# save StartTime
while GPIO.input(GPIO_ECHO) == 0:
StartTime = time.time()
# save time of arrival
while GPIO.input(GPIO_ECHO) == 1:
StopTime = time.time()
# time difference between start and arrival
TimeElapsed = StopTime - StartTime
# multiply with the sonic speed (34300 cm/s)
# and divide by 2, because there and back
distance = (TimeElapsed * 34300) / 2
return distance
def us_act();
# stop, go backwards, turn left twice, stop, and then go forwards again.
global PWM_value
logger.debug('React to distance result')
on()
time.sleep(0.2)
mbackwards()
motorleft
motorleft
on()
time.sleep(0.2)
up_15()
# **** Run Program ***
def main():
client.subscribe("rc-car-pwm")
client.on_message = on_message
client.loop_forever()
main()
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