[HOT] Smartphones using wifi in the field If you ain't in the field or techie ignore this post.

john whelan jwhelan0112 at gmail.com
Wed Feb 3 18:08:32 UTC 2016

It also works on an ASUS RT-N66U which is a conventional wifi router but
has greater range than a lap top hot spot or smartphone.  If it works on
that it should work on anything as a single hub.  It's only if you want to
mesh them that it gets more complicated.

Cheerio John

On 3 February 2016 at 11:54, john whelan <jwhelan0112 at gmail.com> wrote:

> Oh one last thing, there is a difference between a very small network and
> one that gets a bit bigger.
>  https://commotionwireless.net/docs/cck/networking/guidelines-for-mesh/
> talks about some of the design considerations and note that more hops mean
> slight delays which isn't so good for voice.
> Cheerio John
> On 3 February 2016 at 11:16, john whelan <jwhelan0112 at gmail.com> wrote:
>> With fifty users sharing files you probaly want to use a couple of linked
>> hubs, that's where the TP-LINK MR3020 starts to shine.  I have one here and
>> one waiting to be picked up at the computer store to test but its freezing
>> rain here in Ottawa at the moment so there is a layer of ice on the
>> sidewalk, not so good for walking on.  However you can use two laptops
>> independantly and collate the files later on.
>> If you are texting only then one hub should be enough for fifty users,
>> for voice calls depending on the traffic it should just work since not
>> everyone will be using it at the same time.  For file transfer, depending
>> on the size of the files you might want to split the load over more than
>> one hub.
>> For voice over more than one hub you need to link them so you need two or
>> more TP-Link devices with the special firmware.  Linked in this way you can
>> send a text to a device that is not available and in theory it will be
>> delivered when it comes in range next.
>> From a practical point of view Paul's mesh extender combines a hub with a
>> small radio so you can link over longer distances.  It uses the same
>> frequency as a car garage opener to build the mesh.  It also comes in a
>> plastic box to keep the weather out.  Unfortunately it's not quite in
>> product yet but bug New Zealand's Red Cross and they should have some idea
>> of time frames.
>> If you're using a TP-LINK MR3020 it does require a power source, but
>> battery powered USB boxes are around to extend the battery life of a
>> smartphone.
>> http://developer.servalproject.org/dokuwiki/doku.php
>> https://en.wikipedia.org/wiki/Serval_project
>> It appears you can use any wifi hub that supports peers.  Note this isn't
>> quite the approach that the Serval team has been using up until now and I'd
>> need to play with the specific router to get the configuration sorted out
>> so stay with the specific Tp-link device or the win 10 hot spot and test it
>> before you go out in the field.
>> The portable wifi hub the TP-link is cheaper than a laptop, around $40
>> locally.  If you want to link them up then you need to flash them with a
>> different firmware.  I haven't done this yet but it is on the to do list
>> and it should be possible with a laptop but does require running some form
>> of unix on the laptop but that can be done under windows.  Once it is set
>> up then it takes a couple of minutes to update the firmware on the hub.
>> Want me to write up the process on how to configure one for stand alone
>> use?  Where would you like this written up?  Note different coutries have
>> slightly different rules for wifi etc. and a standard TP-Link hub
>> understands these so which country it will be used in is part of the setup
>> process.  Hopefully the linking firmware takes this into account.
>> Note there are other solutions than serval for sharing files, especially
>> using a hot spot from a laptop.  Essentially you can use the laptop as a
>> web server, in theory you just need the appropiate .html file(s) on the
>> laptop.  So you can link windows laptops together using this technique you
>> don't need serval for this.
>> If you use html5 code and have the downloads as .zips then you should be
>> able to click on the link and the file will download automatically.  I have
>> some simple sample html5 code floating around if anyone wants some.  I
>> think most smartphones can handle .zip files.
>> The other thing to note is that wifi devices such as Nexus 7 tablets can
>> use voice to smartphones running Serval.  In general wifi tablets are
>> cheaper than smartphones.
>> and you thought the HOT mailing list was just about mapping.
>> Cheerio John
>> On 3 February 2016 at 09:02, Mhairi O'Hara <mhairi.ohara at hotosm.org>
>> wrote:
>>> Cheers John! We're collecting data on financial services, education and
>>> health facilities in Eastern Uganda and are looking for sharing solutions
>>> that don't involve the internet. With up to 50 students at times, sharing
>>> files via usb sticks and external hard drives is not ideal as it can be
>>> time consuming. Will look into the setup to see if it could work for us
>>> here.
>>> Mhairi
>>> On Wed, Feb 3, 2016 at 3:00 PM, Katja Ulbert <mail at katja-ulbert.de>
>>> wrote:
>>>> Thanks for this valuable information, John!
>>>> On 31/01/16 22:34, Pete Masters wrote:
>>>> Really interesting, John.... Thanks for the post. Just conducted
>>>> training in DRC on data collection and base mapping. We tried to focus as
>>>> much as possible on offline solutions. Wish I'd read this before we'd been,
>>>> not just after! ;)
>>>> Pete
>>>> On 31 Jan 2016 20:35, "john whelan" < <jwhelan0112 at gmail.com>
>>>> jwhelan0112 at gmail.com> wrote:
>>>>> I've been playing around with Serval software on Android.  Ideally it
>>>>> needs a wifi mesh set up using multiple firmware modified TP-Link MR3020
>>>>> portable routers with custom software connected to a small radio device
>>>>> which turns it into a mesh extender.
>>>>> The original concept was to turn the smartphone into a router but the
>>>>> latest Android software well anything above 2.2 denies access to do this.
>>>>> Besides which rooting the phone in this manner is not good from the
>>>>> security point of view.
>>>>> However if you are running Windows 10 and your Laptop supports it,
>>>>> most should, you can turn your laptop into a wifi hot spot that other
>>>>> devices can connect to. Note you should not need to be connected to the
>>>>> Internet for this to work.
>>>>> Translation Android smartphones running Serval within say 100 meters
>>>>> of the laptop  can now talk to each other.  I haven't tried a phone call, I
>>>>> don't have two Smartphones to hand, but messaging certainly works.
>>>>> You should also be able to transfer files certainly from one
>>>>> smartphone to another and if Serval doesn't support file transfer to the
>>>>> host laptop there are other apps around that do.  So things like the latest
>>>>> maps for Osmand etc can be brought down once to the laptop then propagated
>>>>> out to smartphones or a smartphone sent by mail, mule etc to the wifi hub
>>>>> can then connect and distribute files etc.
>>>>> I haven't looked at the implications of interconnecting laptops
>>>>> perhaps with cat 5 cables and although phone calls should be fine across
>>>>> one wifi hub theoretically each hub used in the hops adds a small delay so
>>>>> voice quality over multiple hops may not be ideal.
>>>>> Cheerio John
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>>> Email: mhairi.ohara at hotosm.org
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