I have two access points with the same essid. When I do "iwlist scan," my laptop can "see" both of the access points. I want to switch back and forth between access points. For example, iwconfig shows "access Point: " on interface "wlan0." I want to switch the access point to address2. I have tried "iwconfig wlan0 ap " but the access point remains address1. Is there something else I need to do to make it switch access points? I am using Wireless-Tools version 30.
Have you tried iw
sudo iw connect APSSID
Related
First time using Stack overflow so I'll do my best to explain.
TLDR - HOW DO I MAKE A PI PICO W CONNECT TO A NETWORK WITH WPS?
I'm making a thing, that basically checks whether the value of a particular stock has gone up or down and lights up green or red LED's based on whether the price is up or down. That's all well and good, but to do this it needs to connect to wifi, and being that the thing I'm making has no screen, or keyboard, all we have to accomplish this is the LED's (for the device to communicate with us) and whatever button I put on there.
My plan was to have the device look at a file called "your_wifi_details.txt" for the SSID and pass, and if it finds them, connect - if nothing is there, or if it cannot connect using those details, it is to enter "WPS mode" where the lights will flash, and the user presses the WPS button on their router then presses a button on the device.
Everything is wired up and working perfectly aside from I cannot work out how to get WPS to work on a Pi Pico W. I think I've gotten really close, but i'm getting the error "'CYW43' object has no attribute 'scan_wps'"
(The lines of code are:
# If the button is pressed, scan for WiFi networks that support WPS
if not button.value():
sta_if.scan_wps()
# Connect to the first WiFi network that supports WPS
sta_if.connect_wps()
)
Then it goes on to connect to the API's and such to get the stock price and from there everything is good.
Literally everything works, if I manually go into the "your_wifi_details.txt" and put in a correct SSID and password, we're golden, but I can't have users required to download thonny and connect to the device and edit files and yada yada... so I am really hoping this WPS thing can work.
This is the first 'proper' program i've written since starting to learn python so apologies if this is a stupid approach, it's taken a lot or time and confusion to get this far but it's so nearly working, I just need a little help over the finish line so if anyone has faced this problem or can help me toward a solution I'd be super grateful
Here's excerpts from the relevant bits of code that are connected to the problem. There's a lot of "print" debugging commands so I can see in the terminal in Thonny where the program is at and what it's doing, obviously in the final use case there won't be a screen or keyboard so all that stuff will be taken out once development is complete:
import urequests
import network
import time
import machine
#--------------(Stackoverflow comment) then further down
#stackoverflow comment: I don't know why this next line is in bold, it shouldn't be
# Set up the button (connected to pin 15)
button = machine.Pin(15, machine.Pin.IN, machine.Pin.PULL_UP)
print ('pin 15 set as button')
#--------------(Stackoverflow comment) then further down still
while True:
print ('enter while true loop')
# Connect to the WiFi network
sta_if = network.WLAN(network.STA_IF)
#print ('firstline passed, sleeping for 10 seconds')
#ignore this, unnecessary now
#for i in range (0, 20):
# time.sleep(0.55)
# print ('sleeping...')
#print ('nap over, trying to continue..')
sta_if.active(True)
print ('firing up connection')
# Read the WiFi SSID and password from the text file
with open("your_wifi_details.txt", "r") as f:
ssid = f.readline().strip()
password = f.readline().strip()
print ('read your_wifi_details.txt successfully')
# Try to connect to the WiFi network
sta_if.connect(ssid, password)
print ('attempting to connect to wifi')
# Wait until the device is connected to the WiFi network
while not sta_if.isconnected():
# Flash the LEDs to indicate that the device is unable to connect
print ('connection failed, attempting to flash LEDs')
green_led.on()
red_led.on()
time.sleep(0.5)
green_led.off()
red_led.off()
time.sleep(0.5)
# Set up the button (connected to pin 0)
print ('setting up button for WPS')
button = machine.Pin(15, machine.Pin.IN, machine.Pin.PULL_UP)
# If the button is pressed, scan for WiFi networks that support WPS
if not button.value():
sta_if.scan_wps()
# Connect to the first WiFi network that supports WPS
sta_if.connect_wps()
# Save the WiFi SSID and password to the "your_wifi_details.txt" file
with open("your_wifi_details.txt", "w") as f:
f.write(sta_if.config("essid") + "\n")
f.write(sta_if.config("password") + "\n")
print ('wifi details written to file')
# Print the WiFi connection status in the terminal so I can see if it worked
print("Connected to WiFi:", sta_if.isconnected())
A friend of mine got me a EloTouchSystems 2216 AccuTouch USB TouchMoitor, if was apart of a POS system they were replacing, and I am trying to calibrate it on Linux Mint. I have downloaded the xinput_calibrater app and ran it. Here the output from the program:
Calibrating standard Xorg driver "EloTouchSystems,Inc Elo TouchSystems 2216 AccuTouch® USB Touchmonitor Interface"
current calibration values: min_x=0, max_x=65535 and min_y=0, max_y=65535
If these values are estimated wrong, either supply it manually with the --precalib option, or run the 'get_precalib.sh' script to automatically get it (through HAL).
--> Making the calibration permanent <--
copy the snippet below into '/etc/X11/xorg.conf.d/99-calibration.conf' (/usr/share/X11/xorg.conf.d/ in some distro's)
Section "InputClass"
Identifier "calibration"
MatchProduct "EloTouchSystems,Inc Elo TouchSystems 2216 AccuTouch® USB Touchmonitor Interface"
Option "MinX" "5504"
Option "MaxX" "59519"
Option "MinY" "57834"
Option "MaxY" "6123"
Option "SwapXY" "0" # unless it was already set to 1
Option "InvertX" "0" # unless it was already set
Option "InvertY" "0" # unless it was already set
EndSection
I copied the the snippet as directed to the 99-calibration.conf file, and restarted my computer and nothing happened.
I have tried changing the "InvertX" and "InvertY" values to 1 (changing only one at a time) and rebooting after each time with not success. I am at a lose as to what to do. Can someone offer any suggestions, Please.
P.S. The monitor was manufactured by Fujitsu, and I am using the most current version of Linux Mint.
Additional Information: After posting the question, I realized I did not mention what the touch screen was doing. When I touch the screen and move my finger up and down on the screen, the cursor moves in the opposite direction.
I'm new to answer set programming and could use some help. I've been reading this, but still could use some help. How would I use answer set programming to tell if a graph is strongly connected?
My brainstorming:
Graph represented by nodes and edges (ie; node(1..2), edge(1,2), and edge(2,1)).
Now I need rule "strong() :- ......" that is true if the graph is strongly connected.
A graph is strongly connected if you can start at any node and reach any other node by following the edges in the direction(s) they point.
So my program needs to take each node X and go along the directed edges to try and reach every other node. True if it reaches every other node, False otherwise.
Strong() :- ?
First, unless your graph is directed, you have to get the symmetric edges:
edge(X,Y):- edge(Y,X).
Then, you need to tell that two nodes are connected if there is a path between them:
connected(X,Y):- edge(X,Y).
connected(X,Z):- edge(X,Y) ; connected(Y,Z).
Now, strong holds if for all pairs of nodes, they are connected:
strong:- connected(X,Y): edge(X,_), edge(_,Y).
An alternative version could be:
not_strong:- not connected(X,Y) ; edge(X,_) ; edge(_,Y).
strong:- not not_strong.
(Tested with clingo 4.5.4)
I have a Verilog code simulated and synthesized on ISE design toolkit. I've got an FPGA spartan 6 device which is to be used for the implementation. But there is a problem with the device (probably a power issue) which makes the device unavailable in any of the COM ports when I connected it to my PC. So I want to check whether my Matlab code which I made for serial communication through the device does the desired job. So I need a method to test serial communication via any of the COM ports without connecting a serial com device to the PC. Is there any such method that I can Tx Rx serial data from Matlab to COM ports? Any software or any other method would be highly appreciated :)
I found a way to test Matlab serial communication using virtual serial ports.
Download "Freeware Virtual COM Ports Emulator" from: http://freevirtualserialports.com/
I installed it in Windows 10, and it's working (as trial).
Add a pair of two serial ports:
Execute the following Matlab code sample to verify it's working:
s3 = serial('COM3','BaudRate',115200);
s4 = serial('COM4','BaudRate',115200);
fopen(s3);
fopen(s4);
fwrite(s3, uint8([1, 2, 3, 4, 5]));
%fprintf(s3, '12345');
pause(0.1);
RxBuf = fread(s4, 5)
fclose(s3);
delete(s3);
clear s3
fclose(s4);
delete(s4);
clear s4
The output is:
RxBuf =
1
2
3
4
5
Bypassing the problem "it only stays for a single test session".
There is a problem when creating a pair of virtual ports using the software, it only stays for a single test session.
I guess it's a problem with the COM port emulation software.
The following solution, is not a good practice (and not a true solution).
Declare the serial object as global, keeping the object persistent.
Create the serial object only if it's not created.
Don't delete and don't clear the serial object.
See the following code sample:
global s3 s4
if isempty(s3)
s3 = serial('COM3','BaudRate',115200);
end
if isempty(s4)
s4 = serial('COM4','BaudRate',115200);
end
fopen(s3);
fopen(s4);
fwrite(s3, uint8([1, 2, 3, 4, 5]));
pause(0.1);
RxBuf = fread(s4, 5)
fclose(s3);
%delete(s3);
%clear s3
fclose(s4);
%delete(s4);
%clear s4
You can also look for a better virtual COM port software.
As Rotem suggested, if you need to communicate via serial line between 2 program of your PC you need a virtual COM port emulator.
It seems you are running on Windows OS so I would recommend a completely free emulator (not a trial one). For Windows I use com0com Null-modem emulator (from SourceForge).
In the example below I will show how to communicate with "another" device so Matlab will not handle both side of the communication. The other device will be simulated by a simple terminal. For windows I use RealTerm: Serial/TCP Terminal (also from SourceForge).
Setup:
Execute the setup of both program with all default options. by default com0com will create a virtual pair COM3/COM4 but if these port already exist on your system the program may assign other numbers. Check the numbers before you run the example. (it will also create a CNCA0/CNCB0 pair but you can ignore this one for now).
For RealTerm, once installed (don't forget to activate the server registration at the end of the setup, it should be ticked by default though), it will look like below. Keep all default options, just set the port number and the baud rate if they need to be changed.
Test MATLAB -> Terminal
You are ready to send Ascii characters or binary values from MATLAB to your device. The animation below shows you an example of both option:
you can click on the picture to see it full size. It is running in loop so you may want to wait until it restart from the beginning.
Test Terminal -> MATLAB
Below animation shows you how to test the communication in the other way:
Don't forget to tick [CR] [LF] on RealTerm when you send Ascii characters and want to use the '%s' format specifier on MATLAB, as it needs these characters to detect the end of the string.
Note:
If you have another terminal program that you are more used too, it
will work the same.
If the RealTerm option does not suit you, or if you want to handle
both sides of communication from Matlab, then you can use the code
provided by Rotem in his first answer. Just install com0com but
ignore all the RealTerm part.
I've started using V-Rep to simulate some robots (Pioneers and quadrotors, initially), but I've been having problems when I try to connect it with ROS. I tried to replicate the example from RosTopicPublisherAndSubscriber.ttt and it only works the first time, after I close it and load it again, it doesn't work anymore, my code is practically identical to the example, except that I use getPose and it's a Pioneer (the one that comes with V-Rep), here's my code:
if (simGetScriptExecutionCount()==0) then
-- Check if the required plugin is there (libv_repExtRos.so or libv_repExtRos.dylib):
local moduleName=0
local moduleVersion=0
local index=0
local pluginNotFound=true
while moduleName do
moduleName,moduleVersion=simGetModuleName(index)
if (moduleName=='Ros') then
pluginNotFound=false
end
index=index+1
end
if (pluginNotFound) then
simDisplayDialog('Error','ROS plugin was not found.&&nSimulation will not run properly',sim_dlgstyle_ok,false,nil,{0.8,0,0,0,0,0},{0.5,0,0,1,1,1})
else
-- Retrive the handle of the vision sensor we wish to stream:
lHandle=simGetObjectHandle('Pioneer_p3dx')
-- Now enable topic publishing and streaming of the vision sensor's data:
topicName=simExtROS_enablePublisher('p3dx',1,simros_strmcmd_get_object_pose,lHandle,0,'')
if (topicName == nil) then
simDisplayDialog('Error','Nil',sim_dlgstyle_ok,false,nil,{0.8,0,0,0,0,0},{0.5,0,0,1,1,1})
else
simDisplayDialog('Error','Not Nil',sim_dlgstyle_ok,false,nil,{0.8,0,0,0,0,0},{0.5,0,0,1,1,1})
end
-- Retrive the handle of the passive vision sensor. We will use the passive vision sensor
end
end
Any idea is welcome! Thanks in advance!
PS: Also, if anyone with 1500 reputation points could create the v-rep tag, that would be great!
Ok, the people at V-REP helped me solve it. So basically I should used the argument as -1 instead of 0.
So basically, a should have done this
topicName=simExtROS_enablePublisher('p3dx',1,simros_strmcmd_get_object_pose,lHandle,-1,'')
instead of
topicName=simExtROS_enablePublisher('p3dx',1,simros_strmcmd_get_object_pose,lHandle,0,'')