After the mishaps of a few weeks ago, of trying to compile a full Linux install from scratch for ARM, at the suggestion of a reader here on Hackaday Projects (mschafer), OpenWRT was adopted instead. This may change later, but for now this is the OS we are going with.

With that said, as mentioned in our previous post, we're also using existing hardware, again for the time being. So, as a result, we decided to go with a TP-Link TL-WR841N, for no more reason than the fact that it was the cheapest router available in any convenient location to me, that ran OpenWRT. So, I bought one, brought it home, double-triple-checked it really did run OpenWRT before opening it (thank you student budget), and went ahead and opened it, and wired it to my dev box over ethernet.

Issues with having DHCP for my home router and DHCP from the TP-Link give me 2 default routes notwithstanding, the flash itself was a relatively painless process: download the firmware image, run a firmware upgrade with that as the patch, sit back with a coffee for a few minutes, and watch as the default route issue comes back, but on 192.168.1.0/24 this time, rather than 192.168.0.0/24. Still, easy fix.

A couple of moments later, and I'm telneting into my shiny new router, for which the warranty lasted barely half an hour, and setting a password. As per the instructions, I log out to ssh back in, only to find that ssh did not like that, due to key conflicts. That's right, I forgot, 192.168.1.1 was where I had my server a while ago. Delete the key and try again.

Back in the router, time to get wireless up and running. Following the instructions on the wiki, and again this doesn't take too long. Looks like it's time to up the ante - buy 2 more, for a fully functioning mesh net.

Doing so, flashing as before, and a lot of swearing over having to delete ssh keys every 2 minutes, and I have a basic setup, in which all routers have a password, and OpenWRT. They still need wireless enabling though, so let's do that. This time, I feel confident that I know what I'm doing without consulting the OpenWRT wiki. I vi into /etc/config/wireless, and delete the line disabling wireless, only to find that that's needed. Quick fix, use the UCI tool to re-enable it, and bob's your uncle, 3 routers with wifi enabled. Now what?

Turns out, the OpenWRT wiki is very, very comprehensive, and the UCI tool is very flexible. Setting up wifi was again a matter of following the wiki instructions, editing /etc/config/wireless, reloading the file with UCI, throwing an IP onto the interface, and ping to my hearts content. Repeat for all 3, and a very simple 3-node mesh network now exists on a set of shelves to my right. Now, to make all this happen in about 3 seconds, with no human intervention.