[Commotion-dev] commotion on tp-mr3020 and other low resource devices via extroot

[Ben West]

I've been running TL-MR3020's and TL-WR703N's with moderate success as very
lightweight WasabiNet nodes, albeit not yet with any additional firmware
loaded via USB port.  Just been squeezing everything into 4MBytes.

I believe opkg errors you're seeing are from the commotiond packages, etc,
not being from the same compile run as the stock AA images you're initially
flashing onto the device.  It should work if you flash the device with a
pared-down AA image from the same compile run as commotiond.

I'm attaching the .config I've used for compiling WasabiNet firmware (based
on AA r39154) for TL-MR3020.  This produces an image just about 300kbytes
smaller than the 4MB flash (done partly via the "-funit-at-a-time" compile
optimization), although it excludes luci and any USB support.  This config
also depends on modded versions of libcyassl and libcurl, to permit curl to
operate with the smaller libcyassl library instead of libopenssl.

Since Commotion-OpenWRT doesn't use it, you should be fine to disable
libcurl/curl and then re-enable USB support at whatnot, along with whatever
other pruning is needed to get the image to fit in 4Mbytes.

A couple details I can share about experience with the little TP-Link
units, after having them in regular use for several months now:

1. The popular instructions linked to on the OpenWRT wiki for adding an
external antenna seem to leave the devices badly susceptible to ESD
damage.  I've seen 2 MR3020's mysteriously lose much of their TX power
after lightning storms passed over (even though the units were inside).
This tutorial from a very diligent Australian appears to get it right, by
attaching the antenna pigtail so as not to bypass filter / matching
circuits that could protect the radio chip from surges.  I'm awaiting the
next strong thunderstorm to see if this has any improvement in ESD
protection.
https://forum.openwrt.org/viewtopic.php?id=46543
https://app.box.com/s/cispknq8b9zgog8k5vxn

2. In lieu of external antenna mods possibly not being viable for MR3020 or
WR703N due to ESD vulnerability, I'm hoping to soon check out the TL-MR3220
and/or TL-MR3420.  These units have similar specs, 32MBytes RAM, 4MByte
flash, USB, but they also include stock external antennas *and* LAN ports.
Amazon sells the MR3220 for $30, and Musti claims it could be had cheaper
elsewhere.



On Mon, Jan 20, 2014 at 10:31 AM, Chris Ritzo
<critzo at opentechinstitute.org>wrote:

> Greetings commotion-devs:
>
> I've been working on proof of concept instructions for running Commotion
> Router on lower resource devices with a USB port using OpenWRT's
> extroot, in particular testing on the TP Link MR3020.
>
> If you have comment on improving this test plan, please feel free to
> weigh in. In progress documentation is here:
> https://wiki.commotionwireless.net/doku.php?id=usb_extroot_installation
>
> I've run into a snag which I'm hoping someone might have some ideas
> about resolving. I get dependency errors when attempting to install
> Commotion packages via opkg:
>
> https://wiki.commotionwireless.net/doku.php?id=usb_extroot_installation&#install_commotion_packages_on_the_router
>
> I assume from this error that the stock OpenWRT image needs to have
> kernel (= 3.3.8-1-ccd7796d0ebc3a2e79984d7dd2214393)
>
> At this point I am working on modifying our build server script to
> attempt building an OpenWRT image without Commotion packages but with
> the kernel version we're using when we build with Commotion.
>
> Any ideas appreciated!
>
> --
> Chris Ritzo
> Technologist - Open Technology Institute
> New America Foundation
> _______________________________________________
> Commotion-dev mailing list
> Commotion-dev at lists.chambana.net
> https://lists.chambana.net/mailman/listinfo/commotion-dev
>
>


-- 
Ben West
http://gowasabi.net
ben at gowasabi.net
314-246-9434
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