Cumulus Support

I read that iphone 6 makes for a good pressure measure. So I downloaded the app. And got an image like this below...Question is should I set the Wh-3080 relative pressure to the same value as pressure at sea level or how do I transform the values and set it right on the console?
Do I need to subtract or calculate something? (it seems only relative pressure is possible to change on the fine offset WH-3080)

Yes, you need to set the relative pressure on the console to the sea level pressure reading. You will need to restart Cumulus to get it to pick up the new setting.

Thanks. Sent you 20 GBP for your help and fine software. Decided to go with cumulus. It's just down to easiness, WD was way to complicated.

Hi,

xayide wrote:I read that iphone 6 makes for a good pressure measure.

Interesting.... does anybody know what accuracy it achieves?

I can't see why an (accurate) air pressure sensor would be included in a phone. The GPS was effectively mandated by USA regulations (for the phone to be able to automatically report its location in "911" calls) and now for "added value" features (targetted advertising, etc.).

I'm "suspicious" about that application display, because it would take a very "clever" GPS engine to report the elevation (altitude) to a resolution of 1cm (0.01 metre). Typically, the "real time" accuracy is 1000x worse than that.

Similarly, the app appears to be reporting the pressure to a resolution of about 10 cms (altitude), which is achievable with quite cheap pressure sensors now. But AFAIK that accuracy would require precise calibration, and measurements of temperature and humidy, not likely to be found in a (handheld) mobile phone.

Cheers, Alan.

I just loaded that app (or an Android one that looks similar) on my Nexus 4 which also has a pressure sensor. It asks for the nearest reference station at a similar altitude to you.

It is reading about 0.4 hPa low compared against my VP2, the height is OK to about 1m, I'm indoors near a window.

It looks like the Nexus 4 has a BMP180 and the iPhone 6 has a BMP280

Reason I asked if I could use that info in my fine offset was because of this article:

http://www.extremestorms.com/iphone_6_barometer.htm


Seems the baro in iPhone 6 is actually _very_ good.

The Galaxy S3 is generally within 1mb of VP2 and 'Sea Level' pressure can be entered on the setup screen but doesn't appear to change the displayed value. (On phone display type *#0*# then tap 'sensors')

If I were to calibrate against my local station?
It is here: http://www.wunderground.com/weather-for ... 02550?MR=1


It sits at 223m with 1003 hpa at the moment. (btw I guess WU has relative pressure displayed?)

My station is at around 106 meters so I can't just copy the value and put it in my station right?

My station is currently showing ABS 990.2 and 1003.5 hpa. How would I go along to correct?

Should I just set my station relative to 1003 and be fine with it?

Yes, if that's a trustworthy source of the sea-level pressure in your area, set your relative pressure to be the same. Is that an official station?