Topic: VP2 - reporting indoor temp via APRS

[glormrax]

Hi All,

Not sure this is the best subforum for posting this question but figured I'd start here. What I'm looking to do is be able to report the indoor temp via APRS. The VP2 is installed at our cabin at 5500' with the console inside of course. With APRS and a 2m transceiver I'm able to post all the usual outside parameters. I've not been able to figure out how extract from the console the indoor temp and add that to the APRS WX data stream.

Anyone done something like this with a VP2? I'm open for suggestions on other forums or other places to ask the question.

TIA

[Old Tele man]

Unfortunately, I don't believe that's possible. The VP2 does not include the INSIDE temperature or humidity values in it's output data stream. Additionally, CWOP would mistakenly (because it wouldn't know the temp was INSIDE instead of OUTSIDE) use the temperature as outside value...totally messing up MADIS quality analyses of nearby stations.   

[CW2274]

Unfortunately, I don't believe that's possible. The VP2 doe not include the INSIDE temperature or humidity values in it's data stream output.

Concur.

[bchwdlks]

The VP2 doesn't know inside temp, but put a Meteohub on the console and you could have access to it.

[glormrax]

When running WeatherLink, the inside temp is reported, and if I had a reliable internet connection I could post inside temp. No internet at the cabin, hence the need for APRS.

I was thinking of using APRS to post the temp in a comment block (that's not the right terminology but can't recall details of spec right now), but the problem is how to extract the inside temp? Sounds like I might be out of luck since I'm using the console in strict APRS mode.

[W3DRM]

To re-emphasize Old Tele Man's comment...

Any attempts to modify the data stream of APRS will impact many other users. I would not condone such work regardless of how important it is to an individual and I suspect the folks handling the APRS data would feel exactly the same way.

Better find another way of solving your needs.

[glormrax]

You are assuming that I was planning to modify the APRS protocol. That's a bad assumption on your part. The APRS is designed to be very flexible and can be used to convey information in a multitude of ways.

From the APRS docs at http://www.aprs.net/vm/DOS/WX.HTM:

APRS is idealy suited for SKYWARN with the following features:
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OPERATOR MESSAGES - The Point-to-point message capability can be used for operator to operator messages and alerts. With FILE-PRINT enabled, these messages and WX reports can be scrolled to the printer.
COMMENTS - Transmitted along with each position report, there is a short comment field which can be used to report weather conditions, station status, intentions or other broadcast type information.

In addition to weather data included in position reports, the station STATUS packet is also available for broadcasting additional info. These STATUS packets can be reviewed on the LATEST display. The APRS BULLETIN feature is very powerful as an alerting mechanism to all stations on the net. Even non-packet voice stations making a weather report can be placed on the map (like an object) by another APRS packet operator. His station will appear similar to any other APRS weather station, except that his report will include a marker indicating that he was manually placed on the map by another operator.
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What I originally asked was how to get the indoor temp from the VP2.

TIA

[miraculon]

Since you mention a 2 meter transceiver, I assume that you are a Ham.

I am using a Wx3in1 from Microsat

It is available here in the US from Ham Radio Outlet

I really like this unit. I have a Davis Weather Envoy with USB serial logger feeding the Wx3in1. I just have it uploading to APRS-IS. See it here: http://www.findu.com/cgi-bin/wxpage.cgi?call=KE8DAF-13

At aprs.fi, I have the temperature in the comment field. This is the indoor temperature, with the sensor right behind the Wx3in1. http://aprs.fi/info/a/KE8DAF-13

Here is a raw packet containing the temperature, it is in degrees C however. I don't know if it can be changed to °F, I haven't tried.

***********************************
UPDATE: I looked up how to change to °F and it is very simple. In the line for the beacons, you just change <temp>C to <tempf>F

Code: [Select]

@<date>z<lat>/<long>-PHG4120/WX3in1Plus2.0 U=<volt>V,T=<tempf>FNow it shows:

Code: [Select]

2016-05-06 11:09:52 EDT: KE8DAF-13>APMI06,TCPIP*,qAS,KE8DAF:@061509z4525.03N/08348.63W-PHG4120/WX3in1Plus2.0 U=12.5V,T=65.3F***********************************

Code: [Select]

2016-04-30 07:41:40 EDT: KE8DAF-13>APMI06,TCPIP*,qAS,KE8DAF:@301141z4525.03N/08348.63W-PHG4120/WX3in1Plus2.0 U=12.5V,T=17.5C
I have this defined as a beacon in the Wx3in1.

Code: [Select]

@<date>z<lat>/<long>-PHG4120/WX3in1Plus2.0 U=<volt>V,T=<temp>C
I had a left over One-Wire thermometer IC Maxim DS18S20, that I used to sense the temperature. I had to add a pull-up resistor to get this to work though. Conveniently, there was a 5V spring-loaded socket right next to the 1-Wire data line to add it.

Note that the indoor temperature is not coming from the Envoy, but from this external DS18S20. The Envoy may not suffer as much indoor temperature error as the consoles, but the remote sensor interfaced to the Wx3in1 can be located wherever you want.

I don't know what TNC or APRS software you use, but this Wx3in1 was a simple enough solution for this APRS-neophyte to get going.

Mateusz SQ3PLX, is really helpful and gives excellent support. If you order directly from him, it takes a couple of weeks to clear customs from Poland. No problem from HRO, but they didn't carry the cables that I needed so I ordered those from Microsat directly.

73 de KE8DAF
Greg H.

[Dave47]

I second the suggested use of the Envoy, I've used it with the standard Davis probe 6477 for a few years now to upload the grass temperature continuously to my PC. I also use it occasionally to check the ISS temperature accuracy.

Incidentally, using it like this, I have the bonus of being able to see roughly how much sunshine we've had, which sometimes helps with my daily weather summary if I'm not at home, asleep or just not paying attention.

[SLOweather]

Unfortunately, I don't believe that's possible. The VP2 does not include the INSIDE temperature or humidity values in it's data stream output. Additionally, CWOP would mistakenly (because it wouldn't know the temp was INSIDE instead of OUTSIDE) use the temperature as outside value...totally messing up MADIS quality analyses of nearby stations.

On page 22 of the Davis Serial Communications Protocol PDF, http://www.davisnet.com/support/weather/download/VantageSerialProtocolDocs_v261.pdf regarding the LOOP command:

The Inside Temperature is at offset 9, 2 bytes. The value is sent as 10th of a degree in F.  For example, 795 is returned for 79.5°F.

The Inside Humidity is at offset 11.

Getting that into an APRS packet is a different animal.

[miraculon]

I forgot to mention that the Wx3in1 works with the standard non-APRS logger dongle. I have a standard serial logger feeding the Wx3in1 from the Envoy. I had "USB" in in my earlier post, sorry.

Greg H.

[glormrax]

Excellent info - thanks guys!

[miraculon]

See the UPDATE to see how to change to °F if interested...

Greg H.