[Dprglist] Roborama & wireless networking

[Mary Mathias]

Carl,
I asked one of my old-time DFW Makers who taught HAM classes for us & he
suggests starting here https://www.aredn.org
for packet radio and mesh networking over ham frequencies.
~Mary

On May 13, 2018 1:26 PM, "Carl Ott via DPRGlist" <dprglist at lists.dprg.org>
wrote:

Thanks to everybody who came to RoboRama yesterday - it seems that
everybody had a good time, we met new visitors & old friends, and we had a
well received contest!

We also had Wi-Fi issues - leading to questions...

Can anybody offer suggestions for the Wi-Fi issue some of us observed
yesterday?

The issue was that as the day went on, and more people surfaced in the
Makerspace, the Wi-Fi environment went from almost tolerable to
***difficult for some - won't work at all for others***.

This forced several of us to use personal access points - which definitely
helped - at least for those using the connection more for telemetry than
'in the loop communication'.  However, I was not able to run at all due to
apparently tight latency/jitter requirements, which became unmet as the
makerspace filled up.  This becomes apparent for my robot when one video
stream receiver (whatever Chrome uses) behaves much better and more
consistently as the environment degrades (still ultimately failing), but
another codec viewing the same stream (ffmpeg + whatever plug-in adapter
RoboRealm uses for RTSP) fails much sooner - 'at the drop of a hat /
network-packet' - completely breaking my control loop, yielding grumpy
scowls and a very still and boring robot...

My question is this - what options should I consider beyond the obvious?

*The obvious options are*

a) keep processing local, get the network out of the loop

b) flip the personal access point an unused Wi-Fi channel
---> e.g. on 5 GHz
---> ie. requiring adding a 5 GHz dongle to R-Pi Zero W (depends on finding
one with compatible driver)
---> or requiring swapping R-Pi Zero for e.g.R-Pi 3 B+ (with built-in 5
GHz, entails considerably more hardware rework to existing robot platform)

c) find an alternate radio strategy

d) give up


Currently, options a and d are off the table, and next steps focus on
option b.

*So my questions for DPRG land:*

*1. for option b:* can anybody recommend an R-Pi Zero W compatible Wi-Fi
dongle with 5 GHz?   If no better out there, I'm gonna try an older /
slightly larger version of this:
https://www.amazon.com/gp/product/B01MY7PL10/ref=ox_sc_mini_detail?ie=UTF8&psc=1&smid=ATVPDKIKX0DER,
with what appears to be a R-Pi compatible open source driver recommended by
the vendor...

*2. **for option c:*  can anybody recommend something small other than
Wi-Fi that can carry low jitter / low latency /  low video resolution (e.g.
160 x 120)  network packets, and interface cleanly to both R-Pi Zero and
Windows?

*3. **for option c:*  has anybody dabbled with network packet data over HAM
frequencies?


Thanks!

Carl

carl.ott.jr at gmail.com





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