Friday, 07 July 2017 19:31

Raspberry Pi - Auto WiFi Hotspot Switch - Direct Connection

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A script to allow the Raspberry Pi to connect to a know wifi router or automatically generate a Non Internet Hotspot Access Point if no network is found. You can then use SSH or VNC on the move and switch between the hotspot and home network without a reboot.

This is suitable for the Pi Zero W which has no Network port or anybody who does not need an internet routed access point on a Raspberry Pi 3. Just for direct Wifi access to the PI when you are out and about.

When i am home I like to have my Raspberry Pi connected to the home network and the internet but when I am out I would like to connect to it via a hotspot using a tablet, phone or laptop.

I wanted a Raspberry Pi that connects to your home networks Wifi when I am at home or generates a wifi Hotspot/Access Point when I am out.

I have done this in a previous script but, this is an updated process and more robust than my original script. So this article is how to setup a Raspberry Pi so it can automatically switch between a network wifi connection and a non internet hotspot.

 

If do require an internet routed hotspot as you have a RPi3 or a RPi 1/2 with a wifi dongle then use my alternative script at Raspberry Pi - Auto WiFI Hotspot Switch Internet

Aim:

  • When your home:   On starting the Raspberry Pi it connects to your home routers wifi
  • When your out: On starting, if any known wifi connection is not found it will generate a hotspot so a direct wifi connection can be made to the Raspberry Pi by a tablet, phone or laptop.
  • While in Hotspot mode for RPi 1/2/3:  if an ethernet cable is connected the Raspberry Pi, then it will NOT have internet access

Additional Features:

Using a Cron, a timer can be setup so the wifi connection can be regulary checked. It will switch between a wifi router and a hotspot without a reboot depending on the results. This is useful for

  • Raspberry Pi in car entertainment systems
  • If the RPi looses wifi connection in your garden or near your home when using the camera or sensors.
  • You run a script or program at home connected to your router and wish to monitor it while you are out. As a hotspot is generated without a reboot the script/program is not interuppted.

It is also possible to run the script from a GPIO button so you can manually run the script to switch depending on where you are.

 

 Requirements:

  • Raspberry Pi Zero W or Raspberry Pi 3
  • Raspberry Pi 1,2 or Zero with a Wifi Dongle*,
  • Wifi already configured for your home router

*some WiFi dongles don't work in adhoc mode or don't work with with the nl80211 driver used in this guide for RPi 3 & zero W inbuilt wifi, so you may want to check this first before starting.

 This setup has only be tested on the Raspbian Jessie OS and a connection has been made to the Hotspot using an Android Tablet, Ipad2 and Windows 10. All worked fine with SSH.

Note: Existing Autohotspot users

If you are currently using one of my older autohotspot scripts and would like to change it to this setup, please read all sections as there are changes to the dnsmasq.conf file, interfaces file, the service file and the autohotspot file.

Note:

Dnsmasq bug: in versions below 2.77 there is a recent bug that may cause the hotspot not to start for some users. This can be resolved by removing the dns-root-data. It may be benificial to do this before you start the rest of the installation as it has been reported that doing it after installation for effected users does not work but you won't know if it is an issue until after the installation is complete.

check your version with : dpkg -s dnsmasq

versions 2.77 and above are ok. If not then try the command:

sudo apt-get purge dns-root-data

thanks to danny for highlighting this.

Step 1:

To start with hostapd hotspot client and dnsmasq lightweight dns server need to be installed.

Open a Terminal session.

Update Raspbian with the latest updates by entering the commands:

sudo apt-get update
sudo apt-get upgrade

 To install hostapd enter the command:

sudo apt-get install hostapd

enter Y when prompted.

To install dnsmasq enter the command:

sudo apt-get install dnsmasq

enter Y when prompted

The installers will have set up the programme so they run when the pi is started. For this setup they only need to be started if the home router is not found. So automatic startup needs to be disabled. This is done with the following commands:

sudo systemctl disable hostapd
sudo systemctl disable dnsmasq

Now the hostspot configuration file can be setup. This contains the name of the WiFi signal you will need to connect to (SSID) and the security password.

To edit the configuration files I will be using the nano text editor but if you prefer an editor with an point and click interface then replace nano with leafpad in the following instructions.

Hostapd Configuration

Using a text editor edit the hostapd configuration file. This file won't exist at this stage so will be blank.

sudo nano /etc/hostapd/hostapd.conf

download file here:

interface=wlan0
driver=nl80211
ssid=RPiHotSpot
hw_mode=g
channel=6
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=1234567890
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
  • The interface will be wlan0
  • The driver nl80211 works with the Raspberry Pi 3 & Zero W onboard WiFi but you will need to check that your wifi dongle is compatable and can use Access Point mode.

For more information on wifi dongles see elinux.org/RPi_USB_Wi-Fi_Adapters

  • The SSID is the name of the WiFi signal broadcast from the RPi, which you will connect to with your Tablet or phones WiFi settings.
  • Channel can be set between 1 and 13. If you are having trouble connection because of to many wifi signals in your area are using channel 6 then try another channel.
  • Wpa_passphrase is the password you will need to enter when you first connect a device to your Raspberry Pi's hotspot. This should be at least 8 characters and a bit more difficult to guess than my example.

To save the config file press ctrl & o and to exit nano press Ctrl & x

Now the defaults file needs to be updated to point to where the config file is stored.
In terminal enter the command
sudo nano /etc/default/hostapd

Change:
#DAEMON_CONF=""
to
DAEMON_CONF="/etc/hostapd/hostapd.conf"

And save.

DNSmasq configuration

Next dnsmasq needs to be configured to allow the Rpi to act as a router and issue ip addresses. Open the dnsmasq.conf file with

sudo nano /etc/dnsmasq.conf

Go to the bottom of the file and add the following lines (download here)


#AutoHotspot Config
#stop DNSmasq from using resolv.conf
no-resolv
#Interface to use
interface=wlan0
bind-interfaces
dhcp-range=10.0.0.2,10.0.0.20,12h

and the save (ctl & o) and exit (ctrl & x)

Step 2:

Now that hostapd and dnsmasq are configured we now need to make some changes to the interfaces file, add a service file and then add the autohotspot script.

Next we need to edit the interfaces file. There will be several entries relating to wlan0 already setup. One line needs to be changed then entries for wlan0 should be as the example below.

Enter

sudo nano /etc/network/interfaces

Add wlan0 to the end of the line auto lo

auto lo wlan0

My interfaces file looks like this


# interfaces(5) file used by ifup(8) and ifdown(8)
# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto lo wlan0
iface lo inet loopback
iface eth0 inet manual
allow-hotplug wlan0
iface wlan0 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
allow-hotplug wlan1
iface wlan1 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

now save (ctrl & o) and exit (ctrl & x)

 autohotspot service file

Next we have to create a service which will run the autohotspot script when the Raspberry Pi starts up.

create a new file with the command

sudo nano /etc/systemd/system/autohotspot.service

Then enter the following text or download here


[Unit]
Description=Automatically generates an internet Hotspot when a valid ssid is not in range
After=multi-user.target
[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/autohotspot
[Install]
WantedBy=multi-user.target

and save (ctrl & o) and exit (ctrl & x)

 

For the service to work it has to be enabled. To do this enter the command

sudo systemctl enable autohotspot.service

Software check:

If your version of Raspbian has been repeatedly upgraded from an old OS image, it is possible that that you don't have the correct wifi tools install. These are installed by default on more recent versions of Raspbian.

to check you have iw installed enter the command

dpkg -s iw

If it is installed the first two lines that shown should be

Package: iw
Status: install ok installed

if not enter the command

sudo apt-get install iw

AutoHotspot Script

This is the main script that will manage your wifi connections between a wifi router and an Hotspot.

It will search for any wifi connection that is setup on you Raspberry Pi by using the details found in /etc/wpa_supplicant/wpa_supplicant.conf

If no wifi signal is found for a known SSID then the script will shutdown the wifi network setup and create a Hotspot. Allowing you to connect to the Raspberry Pi from a wifi device using SSH or VNC.

 The script works with SSID's that contain spaces and by entering your routers MAC address it can be used with hidden SSID's.

Hidden SSIDs

If your routers SSID is not broadcast/hidden then find this section in the script

#Enter the Routers Mac Addresses for hidden SSIDs, seperated by spaces ie
#( '11:22:33:44:55:66' 'aa:bb:cc:dd:ee:ff' )
mac=()

and enter your routers MAC address in the brackets of mac=() as shown in the example. Make sure mutiple MAC addresses are seperated by a space.

 

 Creating the autohotspot script:

Create a new file with the command

sudo nano /usr/bin/autohotspot

and add the autohotspot script. This can be downloaded from here


#!/bin/bash
#version 0.90-N/HS
#You may share this script under the Creative Commons Licience of share alike. www.creativecommons.org
#a reference to RaspberryConnect.com must be included in copies or derivatives of this script. 
#Wifi & Hotspot without Internet
#A script to switch between a wifi network and a Hotspot without Internet
#Works at startup or with a seperate timer or manually without a reboot
#Other setup required find out more at
#http://www.raspberryconnect.com
IFSdef=$IFS
#These four lines capture the wifi networks the RPi is setup to use
wpassid=$(awk '/ssid="/{ print $0 }' /etc/wpa_supplicant/wpa_supplicant.conf | awk -F'ssid=' '{ print $2 }' ORS=',' | sed 's/\"/''/g' | sed 's/,$//')
IFS=","
ssids=($wpassid)
IFS=$IFSdef #reset back to defaults
#Note:If you only want to check for certain SSIDs
#Remove the # in in front of ssids=('mySSID1'.... below and put a # infront of all four lines above
# separated by a space, eg ('mySSID1' 'mySSID2')
#ssids=('mySSID1' 'mySSID2' 'mySSID3')
#Enter the Routers Mac Addresses for hidden SSIDs, seperated by spaces ie 
#( '11:22:33:44:55:66' 'aa:bb:cc:dd:ee:ff' ) 
mac=()
ssidsmac=("${ssids[@]}" "${mac[@]}") #combines ssid and MAC for checking
createAdHocNetwork()
{
    ip link set dev wlan0 down
    ip a add 10.0.0.5/24 brd + dev wlan0
    ip link set dev wlan0 up
    systemctl start dnsmasq
    systemctl start hostapd
}
KillHotspot()
{
    echo "Shutting Down Hotspot"
    ip link set dev wlan0 down
    systemctl stop hostapd
    systemctl stop dnsmasq
    ip addr flush dev wlan0
    ip link set dev wlan0 up
}
ChkWifiUp()
{
        sleep 10 #give time for ip to be assigned by router
	if ! wpa_cli status | grep 'ip_address' >/dev/null 2>&1
        then #Failed to connect to wifi (check your wifi settings, password etc)
	       echo 'Wifi failed to connect, falling back to Hotspot'
               wpa_cli terminate >/dev/null 2>&1
	       createAdHocNetwork
	fi
}
#Check to see what SSID's and MAC addresses are in range
ssidChk=('NoSSid')
for ssid in "${ssidsmac[@]}"
do
     if { iw dev wlan0 scan ap-force | grep "$ssid"; } >/dev/null 2>&1
     then
              ssidChk=$ssid
              break
       else
              ssidChk='NoSSid'
     fi
done
#Create Hotspot or connect to valid wifi networks
if [ "$ssidChk" != "NoSSid" ] 
then
       echo 'Using SSID:' $ssidChk
       if systemctl status hostapd | grep "(running)" >/dev/null 2>&1
       then #hotspot running and ssid in range
              KillHotspot
              echo "Hotspot Deactivated, Bringing Wifi Up"
              wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf >/dev/null 2>&1
              ChkWifiUp
       elif { wpa_cli status | grep 'ip_address'; } >/dev/null 2>&1
       then #Already connected
              echo "Wifi already connected to network"
       else #ssid exists and no hotspot running connect to wifi network
              echo "Connecting to WiFi Network"
              wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf >/dev/null 2>&1
              ChkWifiUp
       fi
else #ssid or MAC address not in range
       if systemctl status hostapd | grep "(running)" >/dev/null 2>&1
       then
              echo "Hostspot already active"
       elif { wpa_cli status | grep 'wlan0'; } >/dev/null 2>&1
       then
              echo "Cleaning wifi files and Activating Hotspot"
              wpa_cli terminate >/dev/null 2>&1
              ip addr flush wlan0
              ip link set dev wlan0 down
              rm -r /var/run/wpa_supplicant >/dev/null 2>&1
              createAdHocNetwork
       else #"No SSID, activating Hotspot"
              createAdHocNetwork
       fi
fi

and save (ctl & o) and exit (ctl & x)

one line goes off the page, for reference this is

wpassid=$(awk '/ssid="/{ print $0 }' /etc/wpa_supplicant/wpa_supplicant.conf | awk -F'ssid=' '{ print $2 }' ORS=',' | sed 's/\"/''/g' | sed 's/,$//')

but it is best to copy the script from the download link.

For the autohotspot script to work it needs to executable. This is done with the command

sudo chmod +x /usr/bin/autohotspot

Thats it, you are ready to go. Now test that everything is working ok.

Thanks to Willem Me and Tino for there contributions to the development of this script.

Testing the Hotspot

To test that the RPi is setup ok reboot the RPI. When the desktop returns you should have the wifi icon Raspbian Pixel WiFI icon by the clock.
For those setting this up on a headerless RPi then you should see the pi on your routers network. 

To test the hotspot works ok edit the ssid name of your router in the wpa_supplicant file.

enter

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

and add 'off' to the end of your routers ssid. For example:


network={
	ssid="mySSID1"
	psk="myPassword"
	key_mgmt=WPA-PSK
}

change to


network={
	ssid="mySSID1off"
	psk="myPassword"
	key_mgmt=WPA-PSK
}

save (ctrl & o) and close (ctrl & x) the file

Now reboot the Raspberry Pi.

Once the RPi is up and running the wifi icon near the clock should now be two arrows facing opposite directions Raspbian Pixel AP mode icon This means it is an access point. On a Tablet, phone or Laptop scan for wifi signals. You should see one for RPiHotSpot.

Select this as the wifi signal to connect to. The password is what you setup in the hostapd.conf file. From my example it is 1234567890

Wifi Connections-android

Local wifi signals in range on Android. Will be RPiHotSpot not RPI3Hot

For SSH and VNC the connection ip is 10.0.0.5 also if you have setup the Rpi as a webserver use the same ip to see the webpage.

For ssh use ssh pi@10.0.0.5

For vnc use 10.0.0.5::5900

 Once you are happy the setup is working ok change the wpa_supplicant.conf file back to your routers ssid. From the next reboot the autohotspot script will manage your wifi connection.

 

Setting up a Timer

If the autohotspot script is set to be run at set intervals, when you go out of range of your home router it will automatically generate a hotspot and then when you get back in range it will deactivate the hotspot and connect to the routers wifi. If you run a program in the background or use programs like tmux then any software you are running will keep working.

If you have an active ssh or vnc session running when the switch happens it will be lost.

Using a Cron job, tasks can be set off automatically at certain times, dates or intervals. For my use running the script every 5 minutes is fine but this can be changed to your needs. To setup a cron task enter the command

crontab -e

At the bottom of the file enter the command

*/5 * * * * sudo /usr/bin/autohotspot >/dev/null 2>&1

There is a space after each entry and * except the first *.

The first * position is for minutes. If you want it to check every minute just use * instead of */5

If you want to use hours, say every 2 hours enter it as

* */2 * * * sudo /usr/bin/autohotspot >/dev/null 2>&1

 Save the cron tab with ctrl & o and close it with ctrl & x

The cron job will automatically start straight away.

Disable Cron Timer

If you no longer need the timer running edit the cron with

crontab -e

and put a # infront so it is now

#*/5 * * * * sudo /usr/bin/autohotspot

The script will now only work at boot up or if you manually run the autohotspot script with the command

sudo /usr/bin/autohotspot

Note on Permissions:

by default the pi user does not need to enter a password to use the sudo command. If you are not using the default pi user and while doing this guide you have had to enter a password every time sudo is needed then you will find the the cron job will not work as it wont have permission to run the autohotspot script.

To fix this you can give the user permission to run the script without a password.
Enter the command

sudo visudo

enter your password
at the bottom of the file add the following line, where username is the user that will be using the script:

username ALL= NOPASSWD: /usr/bin/autohotspot

Now you will be able to run the script with sudo with the cron.

Thanks to Jim for pointing this out as an issue for some users.


 

Script Removal

If you don't wish to continue using the autohotspot script then the Raspberry Pi can be revered back to a standard wifi setup with the following steps.

Disable the script with the command

sudo systemctl disable autohotspot

Then reboot.

The autohotspot script will no longer have control of you wifi. Dnsmasq and hostapd can be uninstalled if you no longer need them.

 Trouble Shooting

  • If you get no wifi connection or no hotspot and have this icon Network Downthen it is most likely the autohotspot script is not executable or the service has not been enabled

redo the follow commands

sudo chmod +x /usr/bin/autohotspot

 

sudo systemctl enable autohotspot.service

 

  • You are in range of your router but it only creates a hotspot. If there is an issue with connecting to the router, such as the password is wrong. The script will fall back to the hotspot so you still have some type of connection. Check your password in the wpa_supplicant.conf file. 
  • You can connect to the hotspot via an Android Phone but you can't get a ssh connection. Some users have found this issue where Android uses there data connection rather than the wifi. Disabeling data has allowed them to use ssh.   
  • If this setup is not working as expected you can check the script for errors by running it manually in a terminal window with the command, sudo /usr/bin/autohotspot ,you can also check the service status with, sudo systemctl status -l autohotspot ,and if the hotspot has failed try, sudo systemctl status -l hostapd
  • You need to add a new wifi network to the RPi but it is in Hotspot mode so you are unable to scan for new wifi signals. You will need to add the new network to /etc/wpa_supplicant/wpa_supplicant manually. Enter the following details replacing mySSID and myPassword with the correct details
network={
	ssid="mySSID1"
	psk="myPassword"
	key_mgmt=WPA-PSK
}
  • Unable to Authenticate the RPIHotSpot connection from another device. Make sure the password for the wifi connection is the one in the hosapd.conf file and not your Raspberry Pi's user password. The default pasword is 1234567890
Last modified on Saturday, 05 August 2017 12:29
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Website: www.raspberryconnect.com

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27 comments

  • Comment Link Graeme Saturday, 05 August 2017 12:40 posted by Graeme

    Hi JM

    Thanks for the reminder, I have put the bug note before step 1 now.
    Interesting you can change the signal strength. Good tip for battery saving features if only planning to be close to the pi in hotspot mode. Thanks

    Report
  • Comment Link JM Saturday, 05 August 2017 02:09 posted by JM

    Graeme, this is a followup on my earlier problem report which was resolved when I purged dns-root-data from the ver 2.76 dnsmasq BEFORE preceding with the actual installation instead of after the original install. I emailed you about that but wanted others to know that it then worked perfectly; many thanks for a very useful script. My application is a remote audio recorder sequenced by cron using the ZeroW. I had a problem with RFI from the WiFi Tx getting into the mic preamp and fixed that by reducing power to 1mW by adding: "iw dev wlan0 set txpower fixed 1" to the script ...... no more RFI and battery capacity let's me run for over 20 hours in the field.

    Report
  • Comment Link Graeme Wednesday, 02 August 2017 20:18 posted by Graeme

    Hi David, Thank you. Happy to share something I needed and was sure others could make use of.

    Report
  • Comment Link David Clapp Wednesday, 02 August 2017 02:33 posted by David Clapp

    Very nice! Both the concept and the instructions.

    Report
  • Comment Link Graeme Tuesday, 01 August 2017 20:53 posted by Graeme

    Hi LQ, thanks, your welcome.

    Report
  • Comment Link LQ Tuesday, 01 August 2017 14:20 posted by LQ

    It worked out perfectly for me, just what I was looking for.

    Thank you so much for writing this up!

    Report
  • Comment Link Graeme Monday, 31 July 2017 21:34 posted by Graeme

    Hi Steve, It sounds like it's being put to good use :) Just wanted to check that the setup didn't cause issues I didn't account for.

    What I can do if it is of any use to you is give you a script that will force it to the hotspot without a reboot, regardless of wifi available. You can run this from any folder you choose. Then when you need wifi back run sudo /usr/bin/autohotspot and it will bring back wifi if it is in range.

    If you are using a timer or trigger to run the autohotspot script when it is in forced hotspot mode it will find the wifi network again.

    Let me know if that's of use and I will put it together for you.

    An alternative option is to not put your Uni Wifi in wpa_supplicant.conf so it doesn't use it as standard. If you put the detail in a separate file such as wpa_supplicantUNI.conf. Duplicate the autohotspot script and change the name. In the copy change the references for wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf >/ to the alternate wpa_supplicantUNI.conf

    Then when you manually run the duplicate autohotspot script it will only connect to SSIDs in the wpa_supplicantUNI.conf file.

    When you have finished the downloads run the normal autohotspot script and it will go back to a hotspot as it will use the standard wpa_supplicant.conf file.

    Report
  • Comment Link Steven Monday, 31 July 2017 15:24 posted by Steven

    Hi, Graeme. Thanks for your reply. The issue is related to the way that I am using the Pi. We (my professor and I) are using 3 Raspberry Pis for the computing portion of three different sensors that will be used for non-destructive structural testing. We will use them in the field where no WiFi exists. One of the Pis will be the master, broadcasting an access point. The other Pis will connect to the master. We will be able to SSH to all three with a laptop or a phone in order to run our data collection programs.

    I needed your tutorial, because if the master Pi dies, the other Pis need to automatically create their own network so that we can still SSH to them (no monitor in the field, making it difficult/time consuming to change the configuration manually). The reason I asked this question is because we configure the software in a computer lab at the university. While we are doing that, we need the Pi to ignore the university WiFi in order to simulate the no-WiFi conditions of the field. However, occasionally we need to connect the Pis to the internet through university WiFi in order to download packages, etc. I could probably just add/remove the university network from the list of recognized SSIDs, but I wanted to see if there was an easy way to switch back and forth. This way, I will not list the university network on the list of recognized SSIDs. The Pis will ignore the university WiFi while we are fine tuning the software. I can, however, disable the autohotspot, download a new package from the internet, and then re-enable autohotspot really easily if I need to. Thanks again!

    Report
  • Comment Link Graeme Saturday, 29 July 2017 09:42 posted by Graeme

    Hi Steven, Thanks im glad you find it useful. As you say 'sudo systemctl enable autohotspot' or 'sudo systemctl enable autohotspot.service' will reactivate the script on the next reboot. If you use the cron timer then you will need to also add or remove the # to the line added because manually running sudo /usr/bin/autohotspot will cause it to generate a hotspot if no know ssid is in range.

    Out of interest what issues does this script cause you if you have it running all the time? For my use, other than not being able to scan for new wifi networks when round a friends for example, the wifi mode is the same as when the autohospot script is disabled.

    Report
  • Comment Link Steven Friday, 28 July 2017 21:50 posted by Steven

    Excellent, this is exactly what I am looking for. Thank you for writing it. Question regarding Script Removal: After disabling autohotspot, can I re-enable it with the line 'sudo systemctl enable autohotspot'? I want to be able to switch back and forth between this wifi/hotspot capability and standard wifi setup, because I will need to do this periodically.

    Report
  • Comment Link Graeme Wednesday, 26 July 2017 19:58 posted by Graeme

    Hi Murray, All my Pi's have a hostname setup which I use to connect with in network mode so not knowing the ip is not an issue. Usually not a problem but on rare occasions I can't connect with the host name so have to look up the IP first from my pc or tablet, but in general I connect via ssh with pi@hostname and pi@10.0.0.5 in hotspot mode.
    Hostname can be setup with the raspberry pi configuration menu in preferences or editing the /etc/hostname file. It should just contain the name you want to use.

    Is this what you are after or are you trying to have the same ip/hostname for network and hotspot?

    Report
  • Comment Link Murray Wednesday, 26 July 2017 15:11 posted by Murray

    Hi Graeme, great tutorial, thanks! I have it working across a couple of different networks and as a hotspot. For the sake of consistency when using SSH, I'd like to use a static address. I've managed this when creating the hotspot, but my previous solution doesn't work when connecting to other networks and using "denyinterfaces wlan0" causes it to miss the other networks and create the hotspot anyway. Is there a way to get static IPs using id_str and etc/network/interfaces or is there a different solution?

    Report
  • Comment Link Graeme Sunday, 23 July 2017 12:13 posted by Graeme

    Hi Jim, ok that makes sense. I use the default Pi user account and change the password, sudo is setup by default. I will add a note. Thanks for pointing that out.

    Report
  • Comment Link Jim Buzbee Sunday, 23 July 2017 01:42 posted by Jim Buzbee

    Graeme- I'm using a current version of Raspbian (8, Jessie). But I manually added my account and manually gave that account sudo privileges. Maybe when you go through the guis to create accounts and add sudo privileges, you get sudo access without requiring a password.

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  • Comment Link Graeme Saturday, 22 July 2017 22:57 posted by Graeme

    Hi Jim, glad you have it working now. with sudo I don't get that issue using the cron. I use Ubuntu on my PC and as you say you have to enter a password with sudo but on Raspbian I don't believe I have ever had to enter a password with sudo on any of my Pi's using upgraded images or the latest images. I get the images from the foundations website. Is your version of Raspbian from the foundations website or from another source?

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  • Comment Link Jim Buzbee Saturday, 22 July 2017 16:15 posted by Jim Buzbee

    Graeme- You might also make a note that your described usage of the cron job requires that the user has configured sudo to not require a password prompt. This was not the case for me. In my case, I just added the cron job to the root account instead of my local account. Also, thanks for the work on this process. It's working fine for me now!

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  • Comment Link Graeme Saturday, 22 July 2017 12:58 posted by Graeme

    Hi Jim, your correct there is an issue with that line. A slight oversight on the version that got posted to the site. I have updated the article with the change. Thanks

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  • Comment Link Jim Buzbee Saturday, 22 July 2017 01:21 posted by Jim Buzbee

    I also had issues with an SSID containing blanks until I changed the line:

    if [ $ssidChk != "NoSSid" ]

    to

    if [ "$ssidChk" != "NoSSid" ]

    Consider an SSID of "this is a test". Without quoting the variable, the "if" statement would resolve to:

    if [ this is a test != "NoSSid" ]

    Which would bomb out with an error of "[: too many arguments"

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  • Comment Link Graeme Thursday, 20 July 2017 19:33 posted by Graeme

    Hi Dave, No it won't work with a ' in the ssid as these have to be removed in the string handling of the ssid before the signal is checked.
    If you are manually re-running the autohotspot script after the above error then you will get a RTNETLINK error as the system is in the wrong state to clear it when it needs to. A reboot would get things back under control.

    To flush the system to get it in a usable state instead of reboot requires 4 commands;
    wpa_cli terminate
    ip addr flush wlan0
    ip link set dev wlan0 down
    sudo m -r /var/run/wpa_supplicant

    Then you "should" be able to rerun the script and it will manage the wifi again. But easier to reboot.

    Is there a single quote in your ssid by default? so far I have only come across spaces.

    Let me know if you have further issues and I will see what I can do.

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  • Comment Link Dave Thursday, 20 July 2017 06:42 posted by Dave

    I almost have this working, I'm still trying to fix the v2.76 dnsmasq issue, but in the meantime, it looks like there is a problem parsing ssid's that contain a single quote/apostrophe. (The default apple "Joe Smith's Network" format, for example.) This will result in a " too many arguments" Error. (Line 75 or so?).

    Once I removed the single quote from my wpa_supplicant.conf, I started seeing "RTNETLINK answers: File exists" Errors. I added an extra flush before the down and up in createAdHocNetwork, which might or might not be causing the probs I'm seeing w/ dnsmasq, but at least the script runs for me now. :-)

    I'm doing a full apt-get upgrade (skipped that earlier due to painfully slow connectivity) and will see how things look in the morning.

    Thanks for putting this together, it will definitely solve a lot of problems for me once I get what I am doing wrong figured out!

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  • Comment Link Graeme Tuesday, 18 July 2017 19:46 posted by Graeme

    HI lixi, It should work when the ssid has spaces, it worked fine testing the script.
    Could you add an extra line to the autohotspot script to see what it is searching for.

    Underneath these lines;
    #Check to see what SSID's and MAC addresses are in range
    ssidChk=('NoSSid')
    for ssid in "${ssidsmac[@]}"
    do

    enter echo "Checking SSID: " $ssid

    so it should read

    #Check to see what SSID's and MAC addresses are in range
    ssidChk=('NoSSid')
    for ssid in "${ssidsmac[@]}"
    do
    echo "Checking SSID: " $ssid
    if { iw dev wlan0 scan ap-force | grep "$ssid"; } >/dev/null 2>&1


    then run the script manually with the command
    sudo /usr/bin/autohotspot

    Does the full ssid show or is it split across two lines?

    could you also give me an example of how your ssid is written.

    Thanks

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  • Comment Link lixl Tuesday, 18 July 2017 16:20 posted by lixl

    Great script - thank you very much, but:

    doesn't work with SSIDs which contain a space.
    please be aware of that if the RasPi Starts a Hotspot although the wanted SSID is in reach.

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  • Comment Link Graeme Monday, 17 July 2017 22:17 posted by Graeme

    Hi Jules M, The error you list suggest the service can't run the script /usr/bin/autohotspot but if that was the case you shouldn’t see the wifi RPiHotSpot on windows. Can you try a few things and send me some extra info please.
    in terminal enter sudo /usr/bin/autohotspot this should run the script and give you some feedback, if it works ok try to connect in windows again.

    could you also email me your outputs from:
    sudo systemctl status -l autohotspot

    and in hotspot mode for:
    sudo systemctl status -l hostapd
    sudo systemctl status -l dnsmasq

    Other things to try is check the autohotspot script is executable, enter ls -g /usr/bin/autohotspot
    what it returns should start with -rwxr-xr-x if the x's are missing enter sudo chmod +x /usr/bin/autohotspot and reboot the Pi and see if that works.

    As a double check disable hostapd and dnsmasq again so they don't start at bootup with
    sudo systemctl disable hostapd
    sudo systemctl disable dnsmasq

    When you are in range of your router does it connect ok?

    email: admin@ this site
    and I will look into your issue further.

    Graeme

    update: issue resolved - dnsmasq bug, cleared root dns also interference on channel 6, channel changed. Now working.

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  • Comment Link Jules M Sunday, 16 July 2017 22:45 posted by Jules M

    Tried with a windows XP laptop and Vista laptop .. configured hotspot with and without encryption with the same result ..limited or no connectivity .. had the same problem on an earlier hotspot using dhcp-server but that version would connect if Pi's eth0 port was connected to my home network ???

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  • Comment Link Jules M Sunday, 16 July 2017 21:50 posted by Jules M

    Running the Zero-W with latest update/upgrade as of 0716. Double checked all edits and scripts. dnsmasq was 2.76 so ran purge dns-root-data. The Pi appears on my laptop wireless network list but connection is 'none or limited' and I get error: raspberrypi systemd[1]: autohotspot.service: main process exited, code=exited, status=203/EXEC ... failed state.... any ideas? Thanks.

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  • Comment Link Graeme Tuesday, 11 July 2017 19:54 posted by Graeme

    Hi Mikkel, The example is right, that line should have been altered. Thanks for pointing it out.

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  • Comment Link Mikkel Monday, 10 July 2017 22:17 posted by Mikkel

    In step 2 it is mentioned that any line containing wlan0 should be commented using #, but in the below example there are lines containing wlan0 without the #.
    Is the example or the description correct?

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