[TangerineSDR] Web presentation of magnetometer data to multiple clients

[David Witten]

Hyomin,

Thanks for the links.

The screen capture I posted is from earlier code, and I know the values
were being converted incorrectly at that time.

I was just trying to show folks on the list what was possible with minimal
code.  I will post more screenshots at a later date, perhaps even a live
link if I can.

Dve Witten, KD0EAG


On Tue, Dec 3, 2019 at 8:12 PM Kim, Hyomin <hmkim at njit.edu> wrote:

> Thank you, David!
> Please take a look at the attached figure showing magnetic field
> components near Washington DC based on a magnetic field model. These values
> are what we can expect at the location. Thus your magnetometer reading
> should be similar to these. The values in your figure seem too big.
>
> The northward (X) and eastward (Y) are in the horizontal field while the
> downward (Z) points toward the center of the earth. Thus the plane
> containing X and Y should be leveled. There are some different ways to
> define where X and Y should point to. Here in the figure, X is pointing to
> the geographic north and Y to the geographic east. Anyways, a quick and
> dirty way to make sure your magnetometer reading is correct is to calculate
> SQRT(X^2+Y^2+Z^2) from your reading to see if this value is close to the
> total intensity (F) in the figure. Of course, the value varies depending on
> where you are.
>
> Visit the website: http://wdc.kugi.kyoto-u.ac.jp/igrf/point/index.html and
> enter the coordinates of your location to see expected magnetic fields of
> your location.
>
> Hope this helps.
>
> Hyomin KD2MCR
>
>
>
>
> [image: NJIT logo] <https://www.njit.edu/> *Hyomin Kim*
> Assistant Professor
> Physics
> Center for Solar-Terrestrial Research
> Institute for Space Weather Sciences
> hmkim at njit.edu • (973) 596-5704
> https://web.njit.edu/~hmkim/
> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>
>
> On Tue, Dec 3, 2019 at 4:02 PM Dr. Nathaniel A. Frissell Ph.D. via
> TangerineSDR <tangerinesdr at lists.tapr.org> wrote:
>
>> Thank you, David. This looks good! Do you think you could add in a time
>> series line plot of the Bx, By, and Bz coordinates? I think this would be
>> useful to have right away, even for diagnostics.
>>
>>
>>
>> 73 de Nathaniel W2NAF
>>
>>
>>
>> *From: *TangerineSDR <tangerinesdr-bounces at lists.tapr.org> on behalf of
>> TangerineSDR Listserv <tangerinesdr at lists.tapr.org>
>> *Reply-To: *TangerineSDR Listserv <tangerinesdr at lists.tapr.org>
>> *Date: *Tuesday, December 3, 2019 at 1:49 PM
>> *To: *TangerineSDR Listserv <tangerinesdr at lists.tapr.org>
>> *Cc: *David Witten <wittend at wwrinc.com>
>> *Subject: *[TangerineSDR] Web presentation of magnetometer data to
>> multiple clients
>>
>>
>>
>> All,
>>
>>
>>
>> This is a work in progress, for my own use right now.
>>
>>
>>
>> It shows presentation of magnetometer data in a web browser.  Ignore the
>> actual data shown, it properly signed quantities.
>>
>>
>>
>> The page is served by HTTP, but the sensor data is sent via Websockets.
>> This is done using a golang server (minimal) that launches a program
>> written in C that interrogates the I2C channel. When the golang program
>> detects a browser connection, it serves the web page.  The web page opens a
>> Websockets connection and streams the magnetometer data encapsulated in
>> JSON to the browser client.
>>
>>
>>
>> No web server, as such, is used.  Only one HTTP/HTTPs request is used.
>> There are other possible ways to do this, but this one works well for my
>> purposes.
>>
>>
>>
>> The intent is to have each local host send its lat/long and ip address on
>> startup.  The locations would be indicated on the map.  Clicking on the
>> marker would open a connection to that particular SBC.
>>
>>
>>
>> Data logging locally and remotely could both be controlled.
>>
>>
>>
>> Again this is just eye candy, showing what can be done.  No frameworks,
>> user's language of choice for the service.
>>
>>
>>
>> Dave Witten
>> --
>> TangerineSDR mailing list
>> TangerineSDR at lists.tapr.org
>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>
>
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