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So, currently, I am using multiprocessing to run these 3 functions together.
As only tokens changes, is it recommended to switch to multi-threading? (if yes, will it really help in a performance like speed-up and I think memory will be for sure used less)
This is my code:
from database_function import *
from kiteconnect import KiteTicker
import pandas as pd
from datetime import datetime, timedelta
import schedule
import time
from multiprocessing import Process
def tick_A():
#credentials code here
tokens = [x[0] for x in db_fetchquery("SELECT zerodha FROM script ORDER BY id ASC LIMIT 50")] #FETCHING FIRST 50 SCRIPTS TOKEN
#print(tokens)
##### TO MAKE SURE THE TASK STARTS AFTER 8:59 ONLY ###########
t = datetime.today()
future = datetime(t.year,t.month,t.day,8,59)
if ((future-t).total_seconds()) < 0:
future = datetime(t.year,t.month,t.day,t.hour,t.minute,(t.second+2))
time.sleep((future-t).total_seconds())
##### TO MAKE SURE THE TASK STARTS AFTER 8:59 ONLY ###########
def on_ticks(ws, ticks):
global ltp
ltp = ticks[0]["last_price"]
for tick in ticks:
print(f"{tick['instrument_token']}A")
db_runquery(f'UPDATE SCRIPT SET ltp = {tick["last_price"]} WHERE zerodha = {tick["instrument_token"]}') #UPDATING LTP IN DATABASE
#print(f"{tick['last_price']}")
def on_connect(ws, response):
#print(f"response from connect :: {response}")
# Subscribe to a list of instrument_tokens (TOKENS FETCHED ABOVE WILL BE SUBSCRIBED HERE).
# logging.debug("on connect: {}".format(response))
ws.subscribe(tokens)
ws.set_mode(ws.MODE_LTP,tokens) # SETTING TOKEN TO TICK MODE (LTP / FULL / QUOTE)
kws.on_ticks = on_ticks
kws.on_connect = on_connect
kws.connect(threaded=True)
#####TO STOP THE TASK AFTER 15:32 #######
end_time = datetime(t.year,t.month,t.day,15,32)
while True:
schedule.run_pending()
#time.sleep(1)
if datetime.now() > end_time:
break
#####TO STOP THE TASK AFTER 15:32 #######
def tick_B():
everything remains the same only tokens value changes
tokens = [x[0] for x in db_fetchquery("SELECT zerodha FROM script ORDER BY id ASC OFFSET (50) ROWS FETCH NEXT (50) ROWS ONLY")]
def tick_C():
everything remains the same only tokens value changes
tokens = [x[0] for x in db_fetchquery("SELECT zerodha FROM script ORDER BY id ASC OFFSET (100) ROWS FETCH NEXT (50) ROWS ONLY")]
if __name__ == '__main__':
def runInParallel(*fns):
proc = []
for fn in fns:
p = Process(target=fn)
p.start()
proc.append(p)
for p in proc:
p.join()
runInParallel(tick_A , tick_B , tick_C)
So, currently, I am using multiprocessing to run these 3 functions together.
As only tokens changes, is it recommended to switch to multi-threading? (if yes, will it really help in a performance like speed-up and I think memory will be for sure used less)
most Python implementations do not have true multi-threading, because they use global lock (GIL). So only one thread runs at a time.
For I/O heavy applications it should not make difference. But if you need CPU heavy operations done in parallel (and I see that you use Panda - so the answer must be yes) - you will be better off staying with multi-process app.
I am running a python script on a raspberry-pi.
Essentially, I would like a camera to take a picture every 5 seconds, but only if I have set a boolean to true, which gets toggled on a physical button.
initially I set it to true, and then in my while(true) loop, I want to check to see if the variable is set to true, and if so, start taking pictures every 5 seconds. The issue is if I use something like time time.sleep(5), it essentially freezes everything, including the check. Combine that with the fact that I am using debouncing for the button, it then becomes impossible for me to actually toggle the script since I would have to press it exactly after the 5s wait time, right for the value check... I've been searching around and I think the likely solution would have to include threading, but I can't wrap my head around it. One kind of workaround I thought of would be to look at the system time and if the seconds is a multiple of 5, then take picture (all within the main loop). This seems a bit sketchy.
Script below:
### Imports
from goprocam import GoProCamera, constants
import board
import digitalio
from adafruit_debouncer import Debouncer
import os
import shutil
import time
### GoPro settings
goproCamera = GoProCamera.GoPro()
### Button settings
pin = digitalio.DigitalInOut(board.D12)
pin.direction = digitalio.Direction.INPUT
pin.pull = digitalio.Pull.UP
switch = Debouncer(pin, interval=0.1)
save = False #this is the variable
while(True):
switch.update()
if switch.fell:
print("Pressed, toggling value")
save = not save
if save:
goproCamera.take_photo()
goproCamera.downloadLastMedia()
time.sleep(5)
Here's something to try:
while(True):
switch.update()
if switch.fell:
print("Pressed, toggling value")
save = not save
if save:
current_time = time.time()
if current_time - last_pic_time >= 5:
goproCamera.take_photo()
goproCamera.downloadLastMedia()
last_pic_time = current_time
Depending on exactly what sort of behavior you want, you may have to fiddle with when and how often time.time() is called.
Cheers!
Maybe something like this?
import threading
def set_interval(func, sec):
def func_wrapper():
set_interval(func, sec)
func()
t = threading.Timer(sec, func_wrapper)
t.start()
return t
We call the function above inside the main loop.
Wrap your while loop content on a function:
def take_photo:
goproCamera.take_photo()
goproCamera.downloadLastMedia()
Now we create a flag initially set to False to avoid creating multiple threads.
Notice that I did this before the while loop. We just need a starting value here.
active = False
while(True):
switch.update()
if switch.fell:
print("Pressed, toggling value")
save = not save
if save: # we need to start taking photos.
if not active: # it is not active... so it is the first time it is being called or it has been toggled to save as True again.
photo_thread = set_interval(take_photo, 5) # grabbing a handle to the thread - photo_thread - so we can cancel it later when save is set to False.
active = True # marking as active to be skipped from the loop until save is False
else:
try: # photo_thread may not exist yet so I wrapped it inside a try statement here.
photo_thread.cancel() # if we have a thread we kill it
active = False #setting to False so the next time the button is pressed we can create a new one.
Let me know if it works. =)
What I ended up doing:
### Imports
from goprocam import GoProCamera, constants
import board
import digitalio
from adafruit_debouncer import Debouncer
import os
import time
import threading
### GoPro settings
gopro = GoProCamera.GoPro()
### Button settings
pin = digitalio.DigitalInOut(board.D12)
pin.direction = digitalio.Direction.INPUT
pin.pull = digitalio.Pull.UP
switch = Debouncer(pin, interval=0.1)
### Picture save location
dir_path = os.path.dirname(os.path.realpath(__file__))
new_path = dir_path+"/pictures/"
save = False
### Functions
def takePhoto(e):
while e.isSet():
gopro.take_photo()
gopro.downloadLastMedia()
fname = '100GOPRO-' + gopro.getMedia().split("/")[-1]
current_file = dir_path+'/'+fname
if os.path.isfile(current_file):
os.replace(current_file, new_path+fname) #move file, would be cleaner to download the file directly to the right folder, but the API doesn't work the way I thought it did
e.wait(5)
### Initial settings
e = threading.Event()
t1 = threading.Thread(target=takePhoto, args=([e]))
print("Starting script")
while(True):
switch.update()
if switch.fell:
#toggle value
save = not save
if save:
e.set() #should be taking pictures
else:
e.clear() #not taking pictures
if not t1.is_alive(): #start the thread if it hasn't been yet
if e.is_set():
t1.start()
I have written a sample Subscriber. I want to feed the data that I have obtained from the rospy.Subscriber into another variable, so that I can use it later in the program for processing. At the moment I could see that the Subscriber is functioning as I can see the subscribed values being printed when I use rospy.loginfo() function. Although I donot know how to store this data into another varible. I have tried assigning it directly to a variable by using assignment operator '=', but I get error.
I have tried writing a callback function with rospy.loginfo to print the position data from the subscribed object. I have subscribed JointState and it containes, header, position, velocity and effort arrays. using rospy.loginfo I can verify that the subscriber is subscribing. But when i tried to assign it directly to a variable, I get an error.
I am displaying loginfo from a call back function as follows
def callback(data):
rospy.loginfo(data.position)
global listen
listen = rospy.Subscriber("joint_states", JointState,
callback)
rospy.spin()
and this works fine. But when i slightly modify the code to assign the subscribed values, I get following error i.e.
listen1 = rospy.Subscriber("joint_states", JointState,
callback=None)
listen = listen1.position
#rospy.loginfo(listen)
print(listen)
rospy.spin()```
The error is as follows,
```listen = listen1.position
AttributeError: 'Subscriber' object has no attribute 'position'
EDIT:
Here is my node I have defined in my program,
#rospy.loginfo(msg.data)
global tactile_states
tactile_states = data.data
def joint_callback(data):
#rospy.loginfo(data.position)
global g_joint_states
global g_position
global g_pos1
g_joint_states = data
#for i in len(data.position):
#g_position[i] = data.position[i]
g_position = data.position
if len(data.position) > 0:
print("jointstate more than 0")
g_pos1 = data.position[0]
#print(g_position)
def joint_modifier(*args):
#choice describes what the node is supposed to do whether act as publisher or subscribe to joint states or tactile sensors
rospy.init_node('joint_listener_publisher', anonymous=True)
pub1 = rospy.Publisher('joint_states', JointState, queue_size = 10)
if(len(args)>1):
choice = args[0]
joint_name = args[1]
position = args[2]
else:
choice = args[0]
if (choice == 1):
rate = rospy.Rate(1)
robot_configuration = JointState()
robot_configuration.header = Header()
robot_configuration.name = [joint_name]
robot_configuration.position = [position]
robot_configuration.velocity = [10]
robot_configuration.effort = [100]
while not rospy.is_shutdown():
robot_configuration.header.stamp = rospy.Time.now()
rospy.loginfo(robot_configuration)
break
pub1.publish(robot_configuration)
rospy.sleep(2)
if (choice == 2):
#rospy.Timer(rospy.Duration(2), joint_modifier)
listen = rospy.Subscriber("joint_states", JointState, joint_callback)
rospy.spin()
if (choice == 3):
#rospy.Timer(rospy.Duration(2), joint_modifier)
tactile_sub = rospy.Subscriber("/sr_tactile/touch/ff", Float64, tactile_callback)
rospy.spin()
This is how I am calling the node inside the main body of the program,
joint_modifier(2)
print("printing g_position")
print(g_position)#to check the format of g_position
print("printed g _position")
leg_1 = Leg_attribute(g_position[0], g_position[1], g_position[2], velocity1 = 10, velocity2 = 10, velocity3 = 10, effort1 = 100, effort2 = 100, effort3 = 100, acceleration=1)
When calling this way, the program is stuck at joint_modifier(2) as that function has rospy.spin().
The style which you're using is not very standard. I assume you've seen the example on ROS wiki, I've modified it to demonstrate standard usage below.
Chiefly, addressing the code you posted, you needed to make listen have global scope outside of the callback. This is to store the data you want, not the Subscriber object. The rospy.spin() never goes in a callback, only the main node function/section. The subscriber object, listen1, which is used infrequently, doesn't return anything, and doesn't store the data it acquires. That is, you need Subscriber() to have a non-None callback.
It's more of a bind, giving the data to the callback instead of returning it from Subscriber. That's why listen1 (Subscriber) has no attribute position (JointState).
import rospy
from sensor_msgs.msg import JointState
# Subscribers
# joint_sub (sensor_msgs/JointState): "joint_states"
# This is where you store all your data you recieve
g_joint_states = None
g_positions = None
g_pos1 = None
def timer_callback(event): # Type rospy.TimerEvent
print('timer_cb (' + str(event.current_real) + '): g_positions is')
print(str(None) if g_positions is None else str(g_positions))
def joint_callback(data): # data of type JointState
# Each subscriber gets 1 callback, and the callback either
# stores information and/or computes something and/or publishes
# It _does not!_ return anything
global g_joint_states, g_positions, g_pos1
rospy.loginfo(data.position)
g_joint_states = data
g_positions = data.position
if len(data.position) > 0:
g_pos1 = data.position[0]
print(g_positions)
# In your main function, only! here do you subscribe to topics
def joint_logger_node():
# Init ROS
rospy.init_node('joint_logger_node', anonymous=True)
# Subscribers
# Each subscriber has the topic, topic type, AND the callback!
rospy.Subscriber('joint_states', JointState, joint_callback)
# Rarely need to hold onto the object with a variable:
# joint_sub = rospy.Subscriber(...)
rospy.Timer(rospy.Duration(2), timer_callback)
# spin() simply keeps python from exiting until this node is stopped
# This is an infinite loop, the only code that gets ran are callbacks
rospy.spin()
# NO CODE GOES AFTER THIS, NONE! USE TIMER CALLBACKS!
# unless you need to clean up resource allocation, close(), etc when program dies
if __name__ == '__main__':
joint_logger_node()
Edit 1:
There seems to be some confusion on what Subscriber(), spin(), and _callback(s) do.
It's a bit obscured in the Python, but there is a master program that manages all nodes, and sending nodes between them. In each node, we register with that master program that the node exists, and what publishers and subscribers it has. By register, it means we tell the master program, "Hey, I want that topic!"; in your case, for your (undeclared) joint_sub Subscriber, "Hey, I want all the JointState msgs from the joint_states topic!" The master program will, every time it gets (from some publisher somewhere) a new joint_states JointState msg, send it to that subscriber.
The subscriber handles, deals with, and processes the msg (data) with a callback: when(!) I receive a message, run the callback.
So the master program receives a new joint_states JointState msg from some publisher. Then it, because we registered a subscriber to it, sends it to this node. rospy.spin() is an infinite loop waiting for that data. This is what it does (kinda-mostly):
def rospy.spin():
while rospy.ok():
for new_msg in get_new_messages from master():
if I have a subscriber to new_msg:
my_subscriber.callback(new_msg)
rospy.spin() is where your callback, joint_callback (and/or timer_callback, etc) actually get called, and executed. It only runs when there is data for it.
More fundamentally, I think because of this confusion, your program structure is flawed; your functions don't do what you think they do. This is how you should make your node.
Make your math-portion (all the real non-ros code), the one doing the NN, into a separate module, and make a function to run it.
If you only want to run it when you receive data, run it in the callback. If you want to publish the result, publish in the callback.
Don't call the main function! The if __name__ == '__main__': my_main_function() should be the only place it gets called, and this will call your code. I repeat: the main function, declaring subscribers/publishers/init/timers/parameters, is only run in if __name__ ..., and this function runs your code. To have it run your code, place your code in a callback. Timer callbacks are handy for this.
I hope this code sample clarifies:
import rospy
from std_msgs.msg import Header
from sensor_msgs.msg import JointState
import my_nn as nn # nn.run(data)
# Subscribers
# joint_sub (sensor_msgs/JointState): "joint_states"
# Publishers
# joint_pub (sensor_msgs/JointState): "target_joint_states"
joint_pub = None
def joint_callback(data): # data of type JointState
pub_msg = JointState() # Make a new msg to publish results
pub_msg.header = Header()
pub_msg.name = data.name
pub_msg.velocity = [10] * len(data.name)
pub_msg.effort = [100] * len(data.name)
# This next line might not be quite right for what you want to do,
# But basically, run the "real code" on the data, and get the
# result to publish back out
pub_msg.position = nn.run(data.position) # Run NN on data, store results
joint_pub.publish(pub_msg) # Send it when ready!
if __name__ == '__main__':
# Init ROS
rospy.init_node('joint_logger_node', anonymous=True)
# Subscribers
rospy.Subscriber('joint_states', JointState, joint_callback)
# Publishers
joint_pub = rospy.Publisher('target_joint_states', JointState, queue_size = 10)
# Spin
rospy.spin()
# No more code! This is not a function to call, but its
# own program! This is an executable! Run your code in
# a callback!
Notice that a python module we design to be a ros node, has no functions to be called. It has a defined structure of callbacks and global data shared between them, all initialized and registered in the main function / if __name__ == '__main__'.
I'm working on a Raspberry Pi (3 B+) making a data collection device and I'm
trying to spawn a process to record the data coming in and write it to a file. I have a function for the writing that works fine when I call it directly.
When I call it using the multiprocess approach however, nothing seems to happen. I can see in task monitors in Linux that the process does in fact get spawned but no file gets written, and when I try to pass a flag to it to shut down it doesn't work, meaning I end up terminating the process and nothing seems to have happened.
I've been over this every which way and can't see what I'm doing wrong; does anyone else? In case it's relevant, these are functions inside a parent class, and one of the functions is meant to spawn another as a thread.
Code I'm using:
from datetime import datetime, timedelta
import csv
from drivers.IMU_SEN0 import IMU_SEN0
import multiprocessing, os
class IMU_data_logger:
_output_filename = ''
_csv_headers = []
_accelerometer_headers = ['Accelerometer X','Accelerometer Y','Accelerometer Z']
_gyroscope_headers = ['Gyroscope X','Gyroscope Y','Gyroscope Z']
_magnetometer_headers = ['Bearing']
_log_accelerometer = False
_log_gyroscope= False
_log_magnetometer = False
IMU = None
_writer=[]
_run_underway = False
_process=[]
_stop_value = 0
def __init__(self,output_filename='/home/pi/blah.csv',log_accelerometer = True,log_gyroscope= True,log_magnetometer = True):
"""data logging device
NOTE! Multiple instances of this class should not use the same IMU devices simultaneously!"""
self._output_filename = output_filename
self._log_accelerometer = log_accelerometer
self._log_gyroscope = log_gyroscope
self._log_magnetometer = log_magnetometer
def __del__(self):
# TODO Update this
if self._run_underway: # If there's still a run underway, end it first
self.end_recording()
def _set_up(self):
self.IMU = IMU_SEN0(self._log_accelerometer,self._log_gyroscope,self._log_magnetometer)
self._set_up_headers()
def _set_up_headers(self):
"""Set up the headers of the CSV file based on the header substrings at top and the input flags on what will be measured"""
self._csv_headers = []
if self._log_accelerometer is not None:
self._csv_headers+= self._accelerometer_headers
if self._log_gyroscope is not None:
self._csv_headers+= self._gyroscope_headers
if self._log_magnetometer is not None:
self._csv_headers+= self._magnetometer_headers
def _record_data(self,frequency,stop_value):
self._set_up() #Run setup in thread
"""Record data function, which takes a recording frequency, in herz, as an input"""
previous_read_time=datetime.now()-timedelta(1,0,0)
self._run_underway = True # Note that a run is now going
Period = 1/frequency # Period, in seconds, of a recording based on the input frequency
print("Writing output data to",self._output_filename)
with open(self._output_filename,'w',newline='') as outcsv:
self._writer = csv.writer(outcsv)
self._writer.writerow(self._csv_headers) # Write headers to file
while stop_value.value==0: # While a run continues
if datetime.now()-previous_read_time>=timedelta(0,1,0): # If we've waited a period, collect the data; otherwise keep looping
print("run underway value",self._run_underway)
if datetime.now()-previous_read_time>=timedelta(0,Period,0): # If we've waited a period, collect the data; otherwise keep looping
previous_read_time = datetime.now() # Update previous readtime
next_row = []
if self._log_accelerometer:
# Get values in m/s^2
axes = self.IMU.read_accelerometer_values()
next_row += [axes['x'],axes['y'],axes['z']]
if self._log_gyroscope:
# Read gyro values
gyro = self.IMU.read_gyroscope_values()
next_row += [gyro['x'],gyro['y'],gyro['z']]
if self._log_magnetometer:
# Read magnetometer value
b= self.IMU.read_magnetometer_bearing()
next_row += b
self._writer.writerow(next_row)
# Close the csv when done
outcsv.close()
def start_recording(self,frequency_in_hz):
# Create recording process
self._stop_value = multiprocessing.Value('i',0)
self._process = multiprocessing.Process(target=self._record_data,args=(frequency_in_hz,self._stop_value))
# Start recording process
self._process.start()
print(datetime.now().strftime("%H:%M:%S.%f"),"Data logging process spawned")
print("Logging Accelerometer:",self._log_accelerometer)
print("Logging Gyroscope:",self._log_gyroscope)
print("Logging Magnetometer:",self._log_magnetometer)
print("ID of data logging process: {}".format(self._process.pid))
def end_recording(self,terminate_wait = 2):
"""Function to end the recording multithread that's been spawned.
Args: terminate_wait: This is the time, in seconds, to wait after attempting to shut down the process before terminating it."""
# Get process id
id = self._process.pid
# Set stop event for process
self._stop_value.value = 1
self._process.join(terminate_wait) # Wait two seconds for the process to terminate
if self._process.is_alive(): # If it's still alive after waiting
self._process.terminate()
print(datetime.now().strftime("%H:%M:%S.%f"),"Process",id,"needed to be terminated.")
else:
print(datetime.now().strftime("%H:%M:%S.%f"),"Process",id,"successfully ended itself.")
====================================================================
ANSWER: For anyone following up here, it turns out the problem was my use of the VS Code debugger which apparently doesn't work with multiprocessing and was somehow preventing the success of the spawned process. Many thanks to Tomasz Swider below for helping me work through issues and, eventually, find my idiocy. The help was very deeply appreciated!!
I can see few thing wrong in your code:
First thing
stop_value == 0 will not work as the multiprocess.Value('i', 0) != 0, change that line to
while stop_value.value == 0
Second, you never update previous_read_time so it will write the readings as fast as it can, you will run out of disk quick
Third, try use time.sleep() the thing you are doing is called busy looping and it is bad, it is wasting CPU cycles needlessly.
Four, terminating with self._stop_value = 1 probably will not work there must be other way to set that value maybe self._stop_value.value = 1.
Well here is a pice of example code based on the code that you have provided that is working just fine:
import csv
import multiprocessing
import time
from datetime import datetime, timedelta
from random import randint
class IMU(object):
#staticmethod
def read_accelerometer_values():
return dict(x=randint(0, 100), y=randint(0, 100), z=randint(0, 10))
class Foo(object):
def __init__(self, output_filename):
self._output_filename = output_filename
self._csv_headers = ['xxxx','y','z']
self._log_accelerometer = True
self.IMU = IMU()
def _record_data(self, frequency, stop_value):
#self._set_up() # Run setup functions for the data collection device and store it in the self.IMU variable
"""Record data function, which takes a recording frequency, in herz, as an input"""
previous_read_time = datetime.now() - timedelta(1, 0, 0)
self._run_underway = True # Note that a run is now going
Period = 1 / frequency # Period, in seconds, of a recording based on the input frequency
print("Writing output data to", self._output_filename)
with open(self._output_filename, 'w', newline='') as outcsv:
self._writer = csv.writer(outcsv)
self._writer.writerow(self._csv_headers) # Write headers to file
while stop_value.value == 0: # While a run continues
if datetime.now() - previous_read_time >= timedelta(0, 1,
0): # If we've waited a period, collect the data; otherwise keep looping
print("run underway value", self._run_underway)
if datetime.now() - previous_read_time >= timedelta(0, Period,
0): # If we've waited a period, collect the data; otherwise keep looping
next_row = []
if self._log_accelerometer:
# Get values in m/s^2
axes = self.IMU.read_accelerometer_values()
next_row += [axes['x'], axes['y'], axes['z']]
previous_read_time = datetime.now()
self._writer.writerow(next_row)
# Close the csv when done
outcsv.close()
def start_recording(self, frequency_in_hz):
# Create recording process
self._stop_value = multiprocessing.Value('i', 0)
self._process = multiprocessing.Process(target=self._record_data, args=(frequency_in_hz, self._stop_value))
# Start recording process
self._process.start()
print(datetime.now().strftime("%H:%M:%S.%f"), "Data logging process spawned")
print("ID of data logging process: {}".format(self._process.pid))
def end_recording(self, terminate_wait=2):
"""Function to end the recording multithread that's been spawned.
Args: terminate_wait: This is the time, in seconds, to wait after attempting to shut down the process before terminating it."""
# Get process id
id = self._process.pid
# Set stop event for process
self._stop_value.value = 1
self._process.join(terminate_wait) # Wait two seconds for the process to terminate
if self._process.is_alive(): # If it's still alive after waiting
self._process.terminate()
print(datetime.now().strftime("%H:%M:%S.%f"), "Process", id, "needed to be terminated.")
else:
print(datetime.now().strftime("%H:%M:%S.%f"), "Process", id, "successfully ended itself.")
if __name__ == '__main__':
foo = Foo('/tmp/foometer.csv')
foo.start_recording(20)
time.sleep(5)
print('Ending recording')
foo.end_recording()
Good Day:
I am trying to write some python code to control a gnuradio block. To illustrate the issue I encountered, I have created a simple flowgraph consisting of an audio source connected to the sound card. There is a single gnuradio companion WX GUI element (a variable slider) to control the audio frequency. I tried to take the python code created by gnuradio companion and create an object within python, then create two threads. One thread starts the GNUradio object, the second thread queries the user to input a frequency, then queries the object's frequency and prints it to the terminal for confirmation.
When the code is run, the audio generator starts, the WX GUI slider is shown, and the terminal prompts the user to input a frequency. When the frequency is input via the terminal query, that number is echoed back as expected but the GNUradio block does not change its frequency. Changing the frequency via the WX GUI slider works as expected.
Obviously I'm not linking the variable to the GNUradio block correctly. The code is copied below, any assistance would be appreciated. Thank you.
-Ed
#!/usr/bin/env python2
# -*- coding: utf-8 -*-
##################################################
# GNU Radio Python Flow Graph
# Title: Top Block
# Generated: Wed Oct 4 06:04:54 2017
##################################################
if __name__ == '__main__':
import ctypes
import sys
if sys.platform.startswith('linux'):
try:
x11 = ctypes.cdll.LoadLibrary('libX11.so')
x11.XInitThreads()
except:
print "Warning: failed to XInitThreads()"
from gnuradio import analog
from gnuradio import audio
from gnuradio import eng_notation
from gnuradio import gr
from gnuradio.eng_option import eng_option
from gnuradio.filter import firdes
from gnuradio.wxgui import forms
from grc_gnuradio import wxgui as grc_wxgui
from optparse import OptionParser
import wx
import threading
from threading import Thread
class top_block(grc_wxgui.top_block_gui):
def __init__(self):
grc_wxgui.top_block_gui.__init__(self, title="Top Block")
_icon_path = "/usr/share/icons/hicolor/32x32/apps/gnuradio-grc.png"
self.SetIcon(wx.Icon(_icon_path, wx.BITMAP_TYPE_ANY))
##################################################
# Variables
##################################################
self.samp_rate = samp_rate = 32000
self.freq = freq = 1000
##################################################
# Blocks
##################################################
_freq_sizer = wx.BoxSizer(wx.VERTICAL)
self._freq_text_box = forms.text_box(
parent=self.GetWin(),
sizer=_freq_sizer,
value=self.freq,
callback=self.set_freq,
label="frequency",
converter=forms.float_converter(),
proportion=0,
)
self._freq_slider = forms.slider(
parent=self.GetWin(),
sizer=_freq_sizer,
value=self.freq,
callback=self.set_freq,
minimum=300,
maximum=5000,
num_steps=100,
style=wx.SL_HORIZONTAL,
cast=float,
proportion=1,
)
self.Add(_freq_sizer)
self.audio_sink_0 = audio.sink(samp_rate, "", True)
self.analog_sig_source_x_0 = analog.sig_source_f(samp_rate, analog.GR_COS_WAVE, freq, .25, 0)
##################################################
# Connections
##################################################
self.connect((self.analog_sig_source_x_0, 0), (self.audio_sink_0, 0))
def get_samp_rate(self):
return self.samp_rate
def set_samp_rate(self, samp_rate):
self.samp_rate = samp_rate
self.analog_sig_source_x_0.set_sampling_freq(self.samp_rate)
def get_freq(self):
return self.freq
def set_freq(self, freq):
self.freq = freq
self.analog_sig_source_x_0.set_frequency(self.freq)
self._freq_slider.set_value(self.freq)
self._freq_text_box.set_value(self.freq)
toneGen = top_block()
def runToneGen():
toneGen.Start(True)
toneGen.Wait()
def userInput():
while True:
freq = raw_input("Enter frequency: ")
toneGen.freq = freq
print "tone generator freq set to: ",toneGen.freq," Hz"
#initiate thread to query user for freq
uiThread = Thread(target=userInput, args=())
uiThread.start()
#initiate thread to run gnuradio block
gnuThread = Thread(target=runToneGen, args=())
gnuThread.start()
I believe I have found the answer to my own question. In the code sample above, in the 'userInput()' definition, I was trying to change the frequency of the tone generator block by directly setting the variable 'toneGen.freq'. This did not work. In order to correctly set the frequency the method 'set_freq' in the toneGen object must be used with this syntax:
toneGen.set_freq(int(freq))
this function call will correctly set the audio frequency of the generator and update the UI slider.