Raspberry Pi Auto-Hotspot

Initial software from http://blog.sip2serve.com/post/48420162196/howto-setup-rtl8188cus-on-rpi-as-an-access-point

The concept of headless Pi at Jams and in classrooms has always been a subject close to my heart and recently I’ve been trying to go down the route of a Pi that see if it gets an IP address from a DHCP server, if not – it turns itself into a hotspot so that other computers can connect and communicate to it over WiFi.

So sequence should be

1.  Check if IP been handed out on WiFi from a DHCP server – if OK End

2.  If not, create hotspot for other Pi/clients to use.

The basic software needed is something called hostapd to make the Pi appear as a WiFi access point and dnsmasq so that it can hand out ip addresses to anything connecting to it.

Current situation

Note:  Hopefully this current state will be taken over by @heeedt  https://github.com/heeed/hotpi

Working Hotspot (but no automatic changeover) using 8188CUS based adaptors

To get this working you need to connect your Pi to the internet using a LAN cable.

Then copy and paste this into an LX Terminal session

wget http://git.io/wZV8tg -O ipispot.sh

and then type

sudo bash ipispot.sh

You will be asked a series of questions but unless you an advanced geek or the network you are running on is using 10.0.0.xx addresses – just accept the default for each question

The only exceptions to this would be for your country and WiFi channel number

At the end, it will ask to reboot – once done, you should now see a open ClassPi available WiFi connection that you can connect to.

The hotspot does not supply a bridged connection to your LAN and the internet – (it would be an access point if it did that) it is purely designed to let you connect to it from a WiFi laptop or any WiFI enabled device such as as tablet

Please try and give me feedback

 

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11 Responses

  1. weehorsey says:

    Hi cymplecy

    Works great, been wanting to do this for a while.
    However how do I easily revert back to non hotspot mode?

    Cheers

    Rich

    • cymplecy says:

      The idea is to make it auto-matic so that if it finds a known wifi (e.g at home) then it conencts to that and only goes into hotspot mode when it can’t find normal situation (e.g at a Jam or a mates house)

      So stage 2 is to do that bit 🙂

      Simon

  2. Mark Pearson says:

    Simon – thanks for this – it is looking very good so far.

    One thing I noticed, the script gathers security info, but the generated hostapd.conf file has the security parameters commented out – so the access point comes up with no security in place. Might be worth letting people know about this – and which file to mod if they want to enable security.

    I’m almost up and running – works fine with no security, but when I uncomment the lines in hostapd.conf I can see the AP network, and connect but it gets stuck in an Authentication loop (possibly getting IP ) – but then I had a similar problem when I was setting up an Access point manually (Adafruit tutorial) – must be something I’m doing wrong – or maybe my network dongle – I’ll keep going and see what I can discover.

    • cymplecy says:

      I’m a no security person 🙂 (there’s always a way to crack WiFi so I never botherin the first place)

      The idea is that this will be a fallback mode when it can’t find its normal AP and for primary classrooom use so no password is a requirement but I’ll try and see which lines need uncommenting to enable the password 🙂

      Simon

      • Mark Pearson says:

        Well I’m certainly not a security expert either 🙂 But having just wrestled with this topic and reading multiple online tutorials last week, the topic is fairly fresh for me.

        I believe that after running your script, if you uncomment the lines in the file /etc/hostapd/hostapd.conf and reboot it should come up in “secure” mode and need a WPA/2 password etc.

        Using your script and a different wifi dongle (Edimax) I have a nice “secure” access point working fine – so I suspect that my cheapo £2 wifi dongle is the main problem I was experiencing – it works in AP (access point) mode as long as I don’t require WPA/2 security.

        Thanks for the really useful script – the whole topic continues to be a learning experience for me 🙂

  3. Worth noting that wifi dongles are limited to the number of connections they can make in AP mode,
    and some have really low limits:
    e.g. TP-LINK TL-WN722N can only handle SEVEN clients
    http://www.raspberrypi.org/forums/viewtopic.php?f=36&t=76604
    Simon is using the RTL8188CUS which can go up to 32

  4. Hi Simon

    you say in your Readme that you have this working on a Ralink RT5370 adapter but the current file checks for an RTL8188CUS and throws up an error message if not present. What changes do I need to make to get it to work with the 5370 please.

    Cheers, Daz.

  5. steve gale says:

    Hi,

    I have tried to do this following other instructions and failed, so having seen your post and the successful comments above thought I would give it a try.
    I have copied the line wget …. into a terminal as suggested, press enter and get the following error,
    ….
    HTTP request sent, awaiting response… 302 Found
    Location: https://raw.githubusercontent.com/cymplecy/pispot/master/install_hotspot8188CUS.sh [following]
    –2014-09-30 13:34:46– https://raw.githubusercontent.com/cymplecy/pispot/master/install_hotspot8188CUS.sh
    Resolving raw.githubusercontent.com (raw.githubusercontent.com)… 62.252.172.241
    Connecting to raw.githubusercontent.com (raw.githubusercontent.com)|62.252.172.241|:443… connected.
    GnuTLS: A TLS packet with unexpected length was received.
    Unable to establish SSL connection.
    any ideas what the problem could be?

    I am using a Dexter Industries image but with the text with the above error do not believe this is the problem. Later on this week I will try it with my wheezey image

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