[Commotion-discuss] Consideration for solar-powered urban mesh offering Commotion, Tidepools, Internet access

[Ben West]

I am considering submitting a paper on this topic to the Int'l Summit for
Community Wireless
Networks<http://2013.wirelesssummit.org/content/deadline-extended%E2%80%9430-days-left-submit-proposals>conference,
being held this October in Berlin.  Feel free to respond with
comments, criticisms, and witticisms!

Short TL;DR version: low-cost solar/battery powered wifi mesh to let folks
with smartphones and laptops map out / organize / access resources in their
neighborhood, for semi-casual use during disaster recovery.

Longer version ...

Recent discussion with another St. Louisian pointed toward using the
Tidepools <http://tidepools.co/> application to enable users (accessing
Tidepools via smartphone wifi) to announce and locate resources and
exchange messaging within a neighborhood-wide wifi mesh, say something on
the order of 5 square miles for an initial deployment.

In particular, we were curious whether a *10 or 20-node rooftop mesh
powered entirely by solar/battery*, and with a local Tidepools server
running in that mesh, might make itself handy to folks recently deprived of
electrical power, phone, and other utilities.  Using the mesh could be
further incentivized by also providing limited (~1Mbit/s) Internet access,
to the extent feasible, such that disaster victims could keep up
correspondence via email, Facebook, Twitter, etc.  Furthermore, some of the
roof nodes could have additional hardware to provide *5Volt cell phone
charging ports* at ground level, powered by excess capacity in the node's
solar/battery package.  Also, we assume this mesh would operate 24/7
anyway, i.e. also during non-emergenies, to better familiarize neighborhood
residents with its presence and let them pre-populate the Tidepools map, if
desired.

What I'm curious about is the feasibility of constructing combined antenna
mast + solar panel assemblies that rest on rooftops, anchored by
cinderblocks, with sufficient rigidity/balast to withstand ~60mph wind w/o
damage or significant misalignment.  And for less than 500$US in materials
per rooftop node.  The wifi hotspots themselves create very little wind
loading, so I think a key detail is doing cheap/secure mounting of the
solar panel.  Likewise, I would expect to site rooftop nodes such that a
20-node mesh could continue to operate if even 30% to 40% of the nodes were
knocked offline (e.g. from localized tornado/microburst damage).

This proposal would leverage heavily off the development recently put into
the Commotion Wireless <https://commotionwireless.net/> firmware and
Tidepools <http://tidepools.co/> software developed by the conference
organizer Open Technology Institute <http://oti.newamerica.net/>, along
with the extreme low-cost outdoor mounting techniques I've been developing
via WasabiNet <http://gowasabi.net/content/your-rooftop>.

Your thoughts?

Finally, below is a quick breakdown I made for building a
solar/battery-powered roof node with less than 500$US of materials.
Considering that the wifi hotspot itself draws less than 20W, further
costing-down is possible.  Specifically, a smaller solar panel and smaller
12VDC/24VDC converter should be doable.

   - Ubiquiti Nanostation Loco M2 (runs on 24VDC) - $50

   http://shop.bizsyscon.com/ubiquiti-nanostation-loco-m2-outdoor-mimo-2x2-802-11g-n/

   - 60W 12V Solar Panel - $120

   http://www.amazon.com/Solar-Panel-Crystalline-Energy-Controller/dp/B005HXFWM6

   - 12VDC/6Amp solar charge controller - $50

   http://www.amazon.com/SunSaver-Charge-Controller-12V-6A/dp/B002MQL6L2/ref=sr_1_11

   - OR Cheaper 12VDC/7Amp solar change controller - $20

   http://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI/ref=pd_sim_sbs_hi_5

   - 9-12VDC to 24VDC step-up converter - $120
   http://www.dxengineering.com/parts/sxa-06760

   - 12V Golf Cart battery - $20
   http://www.ecomelectronics.com/prodinfo.phtml?id=2102397

   - DIY mounts made from cinderblocks, treated lumber, conduit, misc parts
   - $30
   http://goo.gl/62jYJ
   http://goo.gl/eU53G

   - ~50ft of shielded cat5 cable (from $150 spool of 1000ft) and ~100ft of
   ground wire - $20

Total materials: $410 per rooftop node (or $380 with cheaper charge
controller)


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