Re: Telemetry


James Ewen
 

You do realize that APRS is just a hack of an existing technology, right?

Pretty tough to try dismissing a new capability as a hack when the whole APRS protocol is a hack. 

Good thing you weren’t around when Bob was dreaming up APRS. 😀

All it takes is one person to “define” a new feature and to implement it. Once enough people use it, it becomes part of the protocol. 



On Tue, Oct 13, 2020 at 8:20 PM Lynn Deffenbaugh <kj4erj@...> wrote:
This is actually just a hack to the findu.com telemetry display and, no,
I don't plan to do it in APRSIS32 as it only applies to displaying
recorded values, not real-time reception of telemetry.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

On 10/13/2020 7:54 PM, Fred Hillhouse wrote:
> I found it!
>
> Fred N7FMH
>
>
> -----Original Message-----
> From: aprssig [mailto:aprssig-bounces@...] On Behalf Of Robert Bruninga
> Sent: Thursday, May 07, 2020 12:53 PM
> To: aprssig@...
> Subject: [aprssig] Dual-use on APRS A/D channels
>
> Steve Dimse has now made it possible for you to make your 5 channels of APRS
> telemetry dual use (up to 10 channels (or more)) and FINDU will properly
> graph the two (or more) different uses of each channel.
>
> I did this on PSAT3 because the current sensor always outputs a positive
> count between 000-999 but changes a digital bit to show if it is positive or
> negative (Charging or discharging).  So I put in a transistor switch on that
> bit and used it to shift the analog output to be 000-500 for load current
> and 500 to 999 for charge current.  And now I can get separate plots for
> each on FINDU.com.
>
> Thus, by using a toggle on all 5 channels, you could extend your APRS
> Telemetry from 5 sensors to ten and still have at least 0.2% accuracy.
>
> Here is the example of the raw data where values below 500 are to be
> interpreted with one equation (load current) and values above 500 are to be
> for charge current and use a different equation...:
>
> http://www1.findu.com/cgi-bin/tele1.cgi?call=psat3,psat3-1&last=36&param=2&b=1&c=0&label=Current&units=Milliamps&autorange=1
>
> When I add "&below=500" to the URLand  use the right equation,  you get the
> bottom LOAD data for values below 500:
> http://www1.findu.com/cgi-bin/tele1.cgi?call=psat3,psat3-1&last=36&param=2&b=1.67&c=-22.5&label=Load%20(only%20bottom%20points)&units=Milliamps&autorange=1&below=500
>
> When I add "&below=-500" (with a minus) to the URL and the right equation
> for this situation, then I get the data points for above 500.
> http://www1.findu.com/cgi-bin/tele1.cgi?call=psat3,psat3-1&last=36&param=2&b=1.635&c=-776&label=Charge%20(only%20top%20points)&units=Milliamps&autorange=1&below=-500
>
> The use of a minus sign to switch "below" to "above" was apparently easier
> to implement than adding a whole new CGI just for "above".
>
> The above plots are on the http://aprs.org/psat3.html  telemetry.
>
> A good example of such use might be the monitoring a battery voltage (that
> rarely changes much) so say it uses values from 000 to 999 to represent
> voltage from 000 to 9.99 volts but never goes below say 6 volts when the
> battry is fully discharged, then that same telemetry channel can also be
> used for another sensor that never goes above 600 by using the "&below=600"
> CGI parameter.
>
> You can see that you could also add a third sensor for example that never
> goes above 300 (or any other lesser value) by adding another plot using
> "&below=300" (as long as the below 600 sensor never goes below 300), etc
>
> Bob, Wb4APR
>
> _______________________________________________
> aprssig mailing list
> aprssig@...
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>
> -----Original Message-----
> From: APRSISCE@groups.io [mailto:APRSISCE@groups.io] On Behalf Of Lynn Deffenbaugh
> Sent: Tuesday, October 13, 2020 6:10 PM
> To: APRSISCE@groups.io
> Subject: Re: [APRSISCE] Telemetry
>
> Nope.  I don't remember that, but Hessu has proposed extending beyond
> the 0-255 values and there's also a Mic-E version of telemetry that goes
> directly in the position packet comment.
>
> Do you have a reference for Bob's proposal?
>
> Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
>
> On 10/13/2020 5:12 PM, Fred Hillhouse wrote:
>> Hi Lynn,
>>
>> It seems not that long ago that Bob, WB4APR, mentioned a possibility to have
>> more telemetry by flipping a bit in the packet. Did you see the post and
>> have you done anything to possibly support it?
>>
>> Thanks!
>>
>> Best regards,
>> Fred N7FMH
>>
>>
>>
>
>
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--
James
VE6SRV

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