Wifi problems with Elementary OS Freya on the ideapad 100

This week I had a problem where wifi suddenly stopped working on my Lenovo ideapad 100 15iby running Elementary OS Freya. I don't know what happened, but suddenly the machine refused to work with any access points. It would say I was connected, and I would have an IP address from DHCP... but there was no actual connection working. Chrome would just complain there was no internet, for example.

I ended up having to rebuild the Realtek rtl8723be wifi driver from the source repository here: https://github.com/lwfinger/rtlwifi_new/ but actually that was not too bad, because the instructions are quite simple. I just had to follow this post which seemed to work fine for me. But I did need to disable the sleep feature of the driver, which is mentioned as an extra step in the instructions. Otherwise the connection would keep dropping and then prompting me for my wifi password all the time.

So that was a slightly annoying problem! But I am pleased to have it sorted out. As I'm writing this I'm downloading a 750Mb file to make sure it's all OK. I'm currently at 500Mb and all is fine, so hopefully that's a job well done.

I have also noticed that Elementary OS Loki is now released, but there is no upgrade route from Freya, so I need to find some free time to do a backup and clean install. Hopefully that will be a smooth process... maybe I'll try running it 'live' first, without installing, to make sure that things work beforehand. That's a job for another day.

PDP-11 wireless internet

To get my PDP-11 on the internet without buying more stuff, I decided to connect my WiFly board to it.  This will allow me to send commands out of the second serial line, which will be dealt with by the WiFly and then sent over the internet.  It means that my PDP will have wireless internet access.  I have knocked up a simple breadboard experiment:

WiFly breadboard for the PDP-11

I realised that I can test this without writing any code, through the magic of the PDP-11's diagnostic commands.  I can use the 'wrap' command, which will send anything I type on the keyboard to the WiFly and then echo any responses from the WiFly back to the console.  It means that I can test without worrying over buggy code or problems in the OS.  It works great; here is an example:

Screenshot of a PDP-11 on the web

Now that I have proved the hardware works together, I can write some C code to do the same and I should have some sort of internet access.  Umm, I wonder how many text-only websites still exist...

WiFly 802.11 b/g Super Module

WiFly Module

I've bought one of these WiFly modules from coolcomponents.co.uk.  It's great!  I'm in the middle of documenting my set up and test procedure, so that life will be easier the next time I set one up.  I have had it acting as a web server (serving up simple pages that were sent to it via RS232).  I have also got it to read other websites and send back the html source over RS232.  Not bad, my next step will be to connect it to an ATmega168 and have some code running on the web without the need for a computer.

So ... I'll post more about that later.