
Noise Mapping with KSQL, a Raspberry Pi and a Software-Defined Radio - h3throw
https://www.confluent.io/blog/noise-mapping-ksql-raspberry-pi-software-defined-radio
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antirez
<JOKE> As the author of dump1090 I'm going to change the license to require
that it is always used together with Redis Streams and not with Kafka. </JOKE>

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Topgamer7
Us hackernewsians have no humor. I'm taking this seriously and forking
dump1090 and calling it dump1337

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bigiain
Bug Report: I'm not receiving any aircraft data on 1337MHz...

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Anechoic
I'd be curious to see how this compares with a real-time flight track/noise
monitoring system (
[https://webtrak.emsbk.com/lax4](https://webtrak.emsbk.com/lax4) at LAX for
example).

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jcims
That’s really cool! I wonder if you can see claps of thunder roll across the
sensors. Would also be interesting to use this to detect planes that aren’t
squitting ADSB.

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whalesalad
This is killer. I’ve been wanting to do something similar to figure out why I
have Bluetooth and WiFi connectivity issues at random parts throughout the
day. I’m thinking there is some kind of interference and would like to prove
that.

This post will serve as a model for that. I’ve had an SDR and a few old Pis
lying around for years... time to dust them off.

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penagwin
I've wanted to do related things with wifi/bluetooth, just a heads up though
that the typical rtl-sdr you find for 20/30$ can't see the 2.4ghz spectrum
which both wifi/bluetooth use (typically)

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simcop2387
May not need to worry about that, the interference can be in other bands if
it's strong enough to blind the other receivers (There's no such thing as a
perfect filter). That said I'd expect that it's going to be someone's
microwave, or similar device, that's just flooding the spectrum around 2Ghz
also.

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Cynddl
> The Raspberry Pi is a little underpowered for serious computation, so I need
> to offload processing to my local Kafka cluster.

Couldn't this be done on the Raspberry Pi with a O(n) search in the
OpenFlights data? Probably less sexy, but a simple grep with location and time
range should be enough.

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jhpankow
That wouldn't show you the real power of KSQL though.

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okigan
hmm, still seems like odd usage.

given that in the end the query goes for specific time window, wouldn't
"regular" sql work fine (vs event processing) ?

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towawayzone
I know I'm completely missing the point, but how does knowing which plane is
upsetting your cat help with the situation? Are you going to report them to
the FAA or something?

P.S. Coming up with examples for things in computer science that aren't absurd
is hard. I had to think of an example when I was explaining junction tables
for many-to-many relationships to someone the other day. After a minute or so
of thinking, I just fell back on that old standard of books and authors.

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minitoar
At first I thought this was about mapping noise around the San Carlos airport,
identifier "KSQL".

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tjohns
Same. I skimmed the article, and was really confused I saw the author talking
about 787s and A380s, because there's no way one of those would fit on the
runway at KSQL.

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nimish
> The Raspberry Pi is a little underpowered for serious computation, so I need
> to offload processing to my local Kafka cluster.

The RPI includes purpose built hardware for DSP in the VideoCore so, probably
not.

Poe's law in action I suppose.

I'm all for big data but this is a case of nuking a fly.

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inetknght
My understanding was that everything on the Pi _except_ for the video
processor was open source. Am I mistaken? Or, are you talking of something
different? Or, do you know of an open source library or demonstration of use
of the VideoCore for DSP?

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Rebelgecko
There's docs and source for some aspects of the VideoCore. I think someone put
together an OpenCL implementation, but I don't know how well it works

Edit: That said, I think any sort of OpenCL/GPGPU solution is overkill for
this problem. I run Flightaware's dump1090 fork on my Pi and it seems to only
use around 30% of one CPU core.

~~~
inetknght
> That said, I think any sort of OpenCL/GPGPU solution is overkill for this
> problem.

For the cost/benefit ratio? I think you're absolutely right.

But I think it'd be a neat project to learn anyway :)

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3xblah
When I hear the term "ksql" I think of Arthur Whitney's ksql and the early
days of kdb, which dates back to the 90's.

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jo-wol
Everything is great in this post except ksql license.

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halbritt
The Confluent Community License?

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legionof7
I've been seeing so many Raspberry Pi projects on HN lately. It's great! I
just got a Zero W and have a B+ lying around that I don't know what to do
with.

