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

Sat Sep 25 03:58:21 PDT 2021

Hi Mitra

> 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.

LoRa is low power, however, WiFi is not. So if you're using WiFi  
adjust your power budget accordingly.

The 20w panel is probably over specced for AU, on the other hand,  
solar is so cheap now, why not overspec. Smoke could reduce the  
available sun by 95% and that extra size might help.

Heat would be your enemy in enclosures. AFAIK LifePo4 is more tolerant  
than other lithium chemistries and probably won't catch fire and  
_cause_ a bush fire. But try and keep them <40c with shading  
https://www.researchgate.net/publication/278708441_LiFePO4_optimal_operation_temperature_range_analysis_for_EVHEV

You might need some ventilation in those enclosures, or look at  
aluminum enclosures with an external heatsink and the chip bonded to  
the aluminum.

> In terms of Dev, I think the most important thing is to have  
> something that sort-of works, good enough to be useful,

I think DR is at that point IMHO, as a backup system. It's not  
something I'd trust my life to.

> At the moment the curve to get involved seems pretty high, without  
> immediately usable results.

What part do you think is most challenging? The devices can be  
purchased pre-flashed, you just need to put them together in the box  
with the instructions and parts list?

> 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).

Yes it should be possible to host the DR-Android.apk on the device for  
download. I did have a go at doing this but ran into some minor  
problem I now can't recall. A file upload web interface like piratebox  
would be a nice to have.

> I read somewhere that SSB is being used,

No that's incorrect AFAIK I don't think any SSB integration has happened.

> I dont' know how well developed the node to node comms are,

Have you explored the protocol documentation?  
https://github.com/sudomesh/disaster-radio/wiki/Protocol

SSB would
> seem like a good idea for that (strong handling of intermittent  
> connections especially)

I think the packet size restriction would make SSB complicated at least.

Excuse brevity, busy day.

Thanks

Sam

> 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
>>
>> _______________________________________________
>> DisasterRadio mailing list
>> DisasterRadio at lists.sudoroom.org
>> https://sudoroom.org/lists/listinfo/disasterradio
>
> -- 
> Mitra Ardron -mitra at mitra.biz  www.mitra.biz
> +61-491-082-515 mobile; +1-510-423-1767 whatsapp

-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-keys
Size: 1348 bytes
Desc: PGP Public Key
URL: <http://sudoroom.org/pipermail/disasterradio/attachments/20210925/b74a3c61/attachment-0001.key>