Calling Weather Experts: What do you Need in a Barograph?

[{151760}]

I don't find that a problem in a yacht. Do you know something I don't?

The OP mentioned 'absolute' pressure. If you take the readings from an uncalibrated barometer they're perfectly usable, but won't be very accurate. Most barometers I've seen come with instructions telling you how to calibrate it so that your readings coincide with the Met Office ones.

 

[nigelmercier]

The OP mentioned 'absolute' pressure. If you take the readings from an uncalibrated barometer they're perfectly usable, but won't be very accurate...

The crazy thing is that the pressure sensors give an absolute digital reading.

 

[{151760}]

The crazy thing is that the pressure sensors give an absolute digital reading.

I guess the NASA one mentioned doesn't have them, then. I confess they're new to me.

 

[prv]

The crazy thing is that the pressure sensors give an absolute digital reading.

Sure, but maybe they expect you to apply any necessary corrections in your software? Assuming we're talking here about a module communicating over I²C or similar?

Pete

 

[adwuk]

The BMP180 module that I have added to my NMEA 2000 gadget came calibrated, but to get accurate measurements I needed to either provide an altitude to get pressure, or pressure to get altitude. I have been using it quite simply, getting air pressure at an altitude of 0. In any case, it seems pretty much in step with the barometric pressures I see on my Davis weather station, and the ones reported by the Met Office.

 

[PotatoNavigator]

The crazy thing is that the pressure sensors give an absolute digital reading.

The big number bottom right is absolute pressure?

 

[grumpy_o_g]

I'm with VicS though the dial doesn't do it for me and I'd spend the extra £300 or so for a new one rather than go secondhand...

If it isn't on paper or soot fixed with hairspray I don't believe it.


This seems to have most of the features you are looking for though, albeit it at a price http://www.bohlken.net/bg/bg1512_en.htm


Edit: Just thought of another option - Airmar's 200WX weatherstation (actually mast head transducers for just about everything except STW and depth) is now available for less than £1000

- but also Airmar's WeatherCaster software may be of interest to you and I think that's free. That takes the input from an Airmar sensor and turns it into graph's, alarms, etc.

 

[jbweston]

I have a Nasa Meteoman barograph. I've been very pleased with it. It's pressure trend (how much, how quickly) I'm interested in, so it does all I need. It sits neatly in the panel over the chart table.

It forgets the pressure calibration between visits to the boat when its power is turned off so I recalibrate it on arrival (usually using QNH reported by the nearest airport - frequently updated on the internet) and then leave it permanently powered up while I'm there.

 

[Boo2]

You can already buy NMEA 2000 barometer with BMP180 sensor from Yacht Devices Ltd.

Nice find !

Boo2

 

[nigelmercier]

Cross reference to similar thread

http://www.ybw.com/forums/showthread.php?453434-How-to-use-barometer-readings