[DisasterRadio] decoupling protocol, software, working hardware, outside-ok hardware

Sat Sep 25 04:15:14 PDT 2021

Mitra, et al,

A few reflections on yours (below) ...

1) These systems (D.R, Meshtastic, ProjectOwl) are meshing, so each 
device passes msgs for the others (in the same encryption group), thus 
extending the range (up to a hop limit)

2) I'd have thought that all (home) devices should be roof mounted, 
o.n.o. Range is pretty awful otherwise. Then there are those on your 
backpack, your car, your nearest tall building or mountain...

3) The 18650 that the T-Beams come with hasn't been enough for my 
experiments. They need to survive days of heavy overcast, partial shade 
up a tree, or bushfire smoke. I've unsoldered the battery holder and 
connected (via a small fuse;), to a 2P or 3P Li-Ion pack, and 5-10w 
solar panel.

4) All of the LilyGo boards work out of the box with minimal geekery, 
there are others like the RAK Wisblock that do way better on power 
consumption, and some great-looking builds of the 1 watt units, etc.

5) All of the systems I've played with allow WiFi connex, but it really 
is intended that each user has a LORA device, and then the BT personal 
area network makes sense. It's the LORA device that has the identity on 
the mesh, not the connected user(s).

I agree about the importance of text messaging, have you considered 
something like https://sourceforge.net/projects/fldigi/files/AndFlmsg/ 
using the AUS UHF CB channels 22 & 23 'Telemetry and Telecommand Only';

I had this working (on the bench) a few months ago - 
https://github.com/paulmandal/atak-forwarder - Haven't toughened it up 
for real-world use yet. There are quite a range of other plugins now for 
Meshtastic.

Re: GregT

1) The LORA Mesh data rates are verry low, and yes, most systems do have 
a way to gateway into a 'Net messaging service.

2) A 911 gateway is above my pay grade, but convincing ppl that they 
don't need a huge PV and home battery just to keep a FTTH terminal alive 
hasn't been easy. Much overkill. When installed in AUS by the telco, 
they still(!) put in a gel-cell, which is compost by the time it's 
needed... Keeping the telco exchange and tower gear running in an outage 
is the hard part of the problem, but that's another story.

3) Regarding device geo-anonymity - I like to see my (T-Beam) repeaters 
on the map, but understand that for some deployments, that's not 
desirable. I've got one of the new-ish RAK Wireless WisBlock devices 
doing repeater service without a GPS. I guess OK once you're network 
topology is worked out.

-

Best advice I can give is 'buy a few boards, and get experimenting...'

73

Greg Hall
0265504481
0428850144
VK2GTH
-

  BUT its also possible to roof mount the node.
>
> For us, its going to have to be WiFi from phone (iPhone or Android) to 
> a node, just because of range - BLE won't cut it without a unit on 
> every house. We would want people un-prepared to connect to the houses 
> that are either pre-prepared, OR easy to setup in an emergency (climb 
> on roof or up tree and zip-tie a node).
>
> I don't see battery power as the issue for the nodes, LoRa is low 
> power - so I'm betting a small solar panel or a larger Lithium battery 
> is going to be fine.
>
> I think for scalability - even to the 10's or small 100s of nodes it 
> would be nice to get pre-made boxes, but at a minimum its got to be 
> off the shelf hardware (like the ESP/LoRa boards) with minimal 
> soldering (add battery, screw into box, flash board). If there is 
> enough demand, maybe someone can create a side-gig supplying them.
>
> In terms of Dev, I think the most important thing is to have something 
> that sort-of works, good enough to be useful, at that point its going 
> to be easier to get people interested enough to improve any 
> incremental part of it. At the moment the curve to get involved seems 
> pretty high, without immediately usable results.
>
> You mentioned small data packets and no images - which makes sense BUT 
> I think (Greg T) you've missed one possibility. That is to hold a 
> simple app at each node. Then a captive WiFi portal can deliver that 
> to an un-prepped phone (Android or iPhone). An ESP32 should be able to 
> do that easily. If this is built as a single-page app (everything 
> locally done in Javascript, not by page loads), and if the comms 
> between the node and the phone, and between nodes are just data (no 
> more images or HTML) then it wouldn't overload even a small ESP32. I 
> haven't dug into the code to see how the existing app is built, I'd 
> probably have designed it using simple JSON queries for ease of 
> development. I read somewhere that SSB is being used, but I'm not sure 
> whether there are JS libraries that would make that easy to integrate 
> to a HTML/JS web app.
>
> I dont' know how well developed the node to node comms are, SSB would 
> seem like a good idea for that (strong handling of intermittent 
> connections especially) though the pool of people who understand it is 
> relatively small, so I'd hope its far enough along that it could just 
> be tweaked as needed - does anyone know ?
>
> Voice would be nice - but I can't see it happening over LoRa - and I 
> haven't seen any other solution that does voice well, is affordable, 
> and doesn't require Ham licenses. I think for our neighbourhood we'll 
> use walkie talkies among pre-prepped people but text is hugely valuable.
>
> Above all, we need solutions that do not require geeks for deployment, 
> many of the ideas I've heard - making home made antennas, soldering up 
> boards, putting together repeaters, etc, just aren't going to be 
> available to most people.
>
> All just opinions - welcome correction !
>
> - Mitra
>
> On 24/9/21 10:58 pm, Greg Troxel wrote:
>> As a lurker, it seems many are interested but we don't really have
>> critical mass.  I see multiple parts as being necessary to eventual
>> success at the "world domination" level, and my inclination from
>> previous software/project experience is to see if they can be separated,
>> to let progress happen somewhat separately.
>>
>> For background, I've worked on several ad hoc radio projects (not open
>> source), done a bit of Amateur Radio packet, and done protocol design
>> and prototype implementation for networking research projects.  Often
>> I've organized these projects into phases to allow incremental funding,
>> with more mature hardware and larger scale at the end.
>>
>> # big picture
>>
>> It seems obvious to me that this entire project is text and small
>> amounts of data only, and no images and no powerpoint files.  And, it's
>> not about providing IP service.
>>
>> I'm unclear on if there is any aspect of connecting to internet or not.
>> It might be good to have a description of which problem is being solved,
>> separately from the description of approach.   I mostly get it, but
>> there's a more detailed view of concept of operations about who does
>> what prep and who wants to talk to who and why.
>>
>> One issue in my area is how to provide 911 service (call to
>> police/fire/ambulance) during an extended power failure.  Very few
>> people have copper pair landlines, almost all have a cellphone, most of
>> them smartphones, and most people have either VZ FiOS (fiber to the
>> home) or Comcast (cable).  Comcast fails after a few hours due to
>> battery-powered equipment on poles, and FiOS works if you can power your
>> ONT (and router, and wifi).  So it would still depend on individuals
>> prepping but a bunch of nodes and people with cell phone battery banks
>> and solar chargers would be at least plausible.  This would lead to
>> wanting some sort of 911 relay with an authorized chat destination.
>>
>> The 911 replacement concept could also benefit from some nodes being
>> internet connected when that works and routing to a computer at the PSAP
>> (911 call taking location) when that is doable, and staying on lora when
>> it is not.  But is very likely be way too much to bit off right now.
>>
>> I am unclear on if chat is 1:1 or group, and how addressing and naming
>> works.  It would seem there are nodes, and then there are users, with
>> perhaps different namespaces.  I'm also unclear on encryption.
>>
>> # protocol
>>
>> It looks like this is defined separately from the code.  Unusual but
>> yay!  There have been recent suggestions about allowing some authorized
>> organizer to control things, and that probably requires configuring
>> public keys.  Baking control into software (vs protocol) feels like the
>> wrong approach architecturally.
>>
>> Scaling is obviously a problem, and it's not clear to me what the story
>> is.  One idea is to keep the number of nodes manageable (100?) via some
>> network id, and another is to have some limited hop count for messages.
>> I will try to read the protocol spec rather than super-skimming.
>>
>> Maybe 15 years ago "Disruption Tolerant Networks" were popular, which is
>> store and forward at the network layer.  Of course it doesn't really
>> matter if this is network or application since that's just a bounday of
>> convenience for thinking.  It's not clear to me how things are and what
>> the long-term view is.
>>
>> Perhaps there should be time sync, perhaps not.  Perhaps only very
>> rough.
>>
>> # prototype hardware instructions
>>
>> Maybe I'm off, but if one gives up power resilience and weather sealing,
>> a protoboard with an ESP32 and a lora module should be enough.  I guess
>> that's the TTGO thing, but ESP32 and lora are easy to get many places.
>>
>> Also, for people in the ham radio world that already have backup power,
>> putting one of these things high in the house  and hooking up to 12V
>> solar-charged batteries is not an unreasonable thing to do.
>>
>> # code
>>
>> More people could hack on code with the above prototype hardware than
>> probably do now.  But maybe I'm confused.
>>
>> I'm unclear on whether the android app for BLE is only useful if one
>> decides to run BLE and not WiFi, or if it's also an alternative backend
>> on wifi.   Perhaps it's just the webapp pre-staged rather than served.
>> Or maybe the webapp comes over BLE?
>>
>> Regarding the android app: f-droid has
>>    Version 1.7 (17) suggested Added on 2020-03-08
>> and if that's old, would be good to figure out how to update.  If it's
>> not old, it might be good to release a micro every 6 months to signal
>> liveness.
>>
>> I know iphones don't allow Free Software, so I wonder if the only path
>> is wifi/web.  And if so, how viable (in the US) the concept of no wifi
>> and using BLE is.  Around me, something that only works on android is
>> just not going to fly outside of the extreme cypherpunk nerd crowd.  (I
>> realize other countries have different prevalances.)
>>
>> Network routing visualization seems maybe missing and would help a lot
>> in understanding an actual network.
>>
>> # geoprivacy
>>
>> I realize there is a map notion, which is fine, but I think it's
>> important to keep the main path of the network not needing to publish
>> coordinates.  I find not wanting to publish location to be correlated
>> with a willingness to spend time prepping.  Maybe that's ok now.
>>
>> # emulator
>>
>> It would be nice if it were possible to run the code with an emulated
>> radio that has a link that acts like lora but is tunneled over the
>> internet to somebody else.   Then the people working on disaster.radio
>> could talk to each other.   I am not sure how hard this would be and if
>> it's worth it though.
>>
>> # power, range and scaling data
>>
>> It's really unclear to me how much power gets used doing what, and if
>> nodes can somehow do fair-share of routing vs high nodes using all their
>> batteries.  But maybe high nodes should just have more power/battery and
>> then it's all good.  It would be nice to have some measurements.
>>
>> It would be nice to have some published anecdata about range.  In the US
>> we're talking 915 I think, for Part 15 compliance, but it would be nice
>> to understand how being able to close a 5W UHF FM link relates to lora
>> links.  (Yes, I know I should just buy a few and try some things; it's
>> on my todo list.)
>>
>> It would be nice to have reports of network sizes and how they work.  In
>> various research projects, it was often a big deal to get the network
>> size up, and I've done demos with 20 wireless nodes, 50 wireless nodes,
>> and 100 wired nodes.  Has anyone built a diaster.radio network more than
>> 10?  25? 50? 100?
>>
>> # deployable hardware design
>>
>> Next is nerd-replicable deployable hardware, and the more it can be buy
>> commodity parts (even if it's plastic food containers that can be hung
>> in a tree with rope), the better.  The key point is a set of recipes.
>>
>> Later comes purchasable hardware.  I suspect that an open hardware
>> design and mature software will lead someone to build and sell nodes, so
>> to me this is the last thing to worry about.
>>
>>
>>
>>
>> I hope at least some of this ranting is helpful.
>>
>> Greg
>>
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> -- 
> Mitra Ardron -mitra at mitra.biz  www.mitra.biz
> +61-491-082-515 mobile; +1-510-423-1767 whatsapp
>
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