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A weatherman in your pocket this is not--but that's not to say it isn't very cool

Google Galaxy Nexus Google

Buried in the avalanche of features in the newest version of Android, Ice Cream Sandwich, was the addition of a new sensor to accompany the standard GPS, proximity, and accelerometer: a barometer. It's one we'd never have thought to add to a smartphone, and we sat for a little while, scratching our heads at the possible use for a sensor that tests atmospheric pressure. So we talked to the experts over at Weather Underground, and got a better sense of what this is--and, more importantly, what it is not.

WHAT'S A BAROMETER?

A barometer is an instrument used primarily to test atmospheric pressure--essentially the weight of air. Invented way back in the 17th century, barometers now come in a few different forms. There's the water-based kind, very similar to the original invention: a sealed glass container with a narrow spout, half full of liquid. Then there's the aneroid barometer, which uses a small cell made of a beryllium/copper alloy that expands or contracts based on atmospheric pressure. But the most modern, smallest barometers, the kind almost certainly used in the new Galaxy Nexus phone, are digital.

Digital barometers are tiny--they're often found in dedicated GPS units and even in those rugged outdoorsy watches--and replace all mechanical parts with a simple pressure-sensing transducer, which measure pressure in Pascals. Of course, these digital barometers have to be calibrated to deliver an accurate reading; you somehow have to be able to give the barometer a constant that is correct. Often that's done by entering your precise elevation, though over time the barometer will suss out the correct readings.

WHY IS IT IN MY PHONE?

I spoke to Jeff Masters, the director of meteorology at Weather Underground, to find out why Google might have chosen to include this surprising sensor in their new flagship phone. His immediate answer? Altitude. "I would expect," he said, "someone will write an app to determine your change in altitude based on your barometer reading." This could be of a lot of use to hikers who want to see how many feet they've climbed, or people curious to find out the pressure inside a train or plane. The phone's always-on internet connection would allow some sharing and crowdsourcing of data, as well. "It would also be cool if you could share your pressure readings with a bunch of other smartphone users to get a super-dense picture of the pressure changes due to an approaching thunderstorm, cold front, or hurricane," says Masters.

But the main use for a barometer is a lot simpler, and a lot more subtle. Says John Celenza, the lead meteorological developer at Weather Underground, "the barometer is probably used on the phone to aid in correcting altitude measurements by the GPS." In other words, the barometer is more likely than not intended to be a source of supplemental data for the GPS sensor, adding altitude measurements for increased accuracy. The atmospheric pressure is directly related to elevation, so a barometer can very easily be used as an altimeter, measuring your altitude.

WHAT CAN'T IT DO?

Our immediate thought upon hearing that Google was implanting a barometer in smartphones was a revolution in weather forecasting. It'd be like a meteorologist, right in your phone! That weather app of yours would get a shot in the arm of pure, hard data, based on exactly where you are, not the closest weather station. You'd be able to crowdsource weather readings to find out what the weather is all around you!

Those are a bit optimistic, it turns out. According to Celenza, "barometric pressure does not change greatly over a small geographic area. For instance, when people calibrate their weather station barometer, they use the nearest airport's barometric pressure reading." The barometric pressure is unlikely to change very much even over several miles, in terms of assisting with weather prediction. "We do not immediately see," said Celenza, "how having a fine-grid of barometric pressure readings is going to substantially help forecasting." So you can forget about having a tiny meteorologist in your pocket.

WHAT ABOUT THE FUTURE?

This isn't to say that the barometer could never be used for all those cool weather forecasting dreams we had. In concert with a few more sets of data, a phone equipped with a barometer really could deliver accurate forecasts for your specific time and place. "If phones could somehow accurately sense temperature, wind speed, and direction, that would be a game-changer," says Celenza. Many smartphones already pack an internal thermometer to sense and regulate the phone's guts--it's not very far-fetched at all to imagine an external thermometer that could measure the outside air.

Wind speed and direction, well, that's a bit harder. The bulky anemometer, invented way back in 1450, is still in wide use, and as a large mechanical device would be pretty hard to translate to a digital form. But there are already wind sensors for our smartphones--apps that use a phone's microphone to hear wind speed. Direction could be sussed out from the phone's position (use the GPS and gyroscope for that), and the microphone can measure speed.

All in all, it's not hard to imagine an all-in-one solution that puts a miniaturized weather station right in your smartphone. And a huge grid of to-the-second weather information could be a pretty amazing resource.

32 Comments

Okay I am probably the only one like this. But for forever I have wanted a barometer built into my pocket watch. Now you could say the have that!

The guys at google sure must be hungry, naming all their operating systems things like gingerbread, froyo, and ice cream sandwich. I remember when stupid software codenames used to be taken off a product when it was commercialized. Now it seems that people think that the more moronic and slapdash the name sounds the better the software must be.

I thought it was used for map software to determine what level of a tall building you are currently on

I also wanted to comment FWIW that anybody who has used a real GPS system for hiking or waypoints will probably notice that the altitude measurements are off by hundreds of feet. GPS has always been notoriously bad for altitudes, so I am glad to see that there is finally an effort to correct this.

They will probably use it for small sport aircraft without radar... I actually came up with the idea a while ago. They would use the GPS and the barometer data to track themselves while flying displaying it on google earth maps on the phone. It could also be used like Find my friends... Create an app that pilots could join and share where they are while flying... Eventually leading to the production of my coined phrase "Flight Path Projection Navigation System". It would allow small aircraft to have basically a early warning collision system that would show you where other pilots are flying in the local area and project out your path and theirs in 3D on the phone screen in real time. Ding Ding I think we have a winner that may save lives :) apparently the airforce has something similar called T CAS but not quite a sophisticated because its just dots on a screen..... So I couldn't really move ahead with my idea... Hopefully someone reads this and makes it happen.

Paraglider, hanglider, and sailplane pilots use digital variometers which are just very sensitive barometers that indicate whether they are climbing or sinking. GPS altimeter data isn't fine enough resolution to do this. It's a very valuable instrument when you depend on thermals to keep you aloft. I'd like to see how sensitive the barometer is in the Nexus Prime. It could also be a useful backup in a sport plane if your instrument panel vario fails.

A barometer which keeps track of the changes in atmospheric pressure ( rising or falling) is a good indication of weather change, without the need for temperature or wind speed indicators.

@aarontco

The reason google names it the way they do is to indirectly make fun of Apple and the names they give their OS.

I've worked with barometers in wearable sensing devices, and they're sensitive enough to tell when you move up or down a floor in a building. So for indoor localization (where am I on a map) applications, they're very useful. Note, however, that the big problem is calibration. The atmospheric pressure changes all the time, so detecting the exact altitude requires careful calibration. Detecting changes in pressure, from walking up a flight of stairs for example, is much easier.

Mood. Barometric pressure affects our mood. This could lead to a lot of neat apps. You phone says "The barometric pressure is 800mm! You should be feeling happy!"

I could also be used for medical stuff as well. I have some sort of undiagnosed condition in my low body that causes a few different pain and sensativity issues. On top of which, during fall, spring and winter my legs have a throbbing dull ache. I'm suspecting that when a weather system comes through (which causes the atmospheric pressure to change slightly) my legs have that dull ache. During summer we don't get much rain so it doesn't happen often and I can deal with it. During those other seasons it happens frequently enough that I have to add on more pain meds on top of what I already take.

There are many others that seem to have the same pain onset reactions. A phone barometer could help remind people to take their meds and possibly help doctors track the reactions. It may even make it possible to experiment and figure out why people have reactions to the atmospheric changes.

Sounds pretty simple to me. You need one extra satellite to provide an altitude reading. If your geocoords are triangulated by satellite, you won't need to call in an extra sat to get your altitude. Hey, anything that saves battery, connections, reliance on external resources sounds good to me!

I adore the competition of these smart phones. They keep getting better and better by all the companies. Though as we put more data in them and rely on them more just remember what happens as it drops in that puddle of water or if it gets hack\virus compromised.

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Android can monitor & control the room temperature level by communicating with Climate-Control systems installed in your home or workplace (via NFC/Bluetooth/Wireless).

Android can ring to your nearest fire-station, in-case it detects fire (as room temperature will be in danger levels)!

Above points are just thoughts/ideas.

Q

Find a bridge of which everyone (anyone) will pass and charge them a penny or even a percentage of a penny and you too can become a billionaire, (GOOGLE).

suddenmischief,
Many GPS units can access far more than three satellites and their altitude measurements are still off by several hundred feet. Triangulation is not enough. A barometer would still be more accurate, though it too is electronic, so I'm not sure it would save the battery. But it will make positioning more accurate.

I have several GPS devices and traveled a lot of places and I can safely say that adding a barometer that can detect elevation will surely help with navigation system, this is especially when you are traveling/navigating down the road, for instance you were stuck on traffic and you want to find an alternate route to you place, the problem you have on your map is you have two parallel road.

1. The upper road (a bridge for instance) this has only one option straight away
2. The lower road (the road underneath the bridge) this road has two turns up ahead one on left and one on right.

Now let say your home is just around that left turn. If your GPS device can detect that you are on the lower road it will just give you direction to turn left, if your GPS device detects that you are on the upper road it will give you a different route to travel. So having only GPS to triangulate your location on a parallel road your GPS device will see you on the same point on map not knowing if you are on the upper or lower side of the road.

"only GPS to triangulate (not included the barometer)"

For pilots who has a GPS flight map navigation this is very useful, this can warn pilot if you are for some reason on an altitude lower than the incoming mountain on your flight path

Great write-up, I am regular visitor of one’s web site, maintain up the nice operate, and It’s going to be a regular visitor for a long time.

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I'm not getting something in this discussion. Doesn't the barometric pressure change as much as several inches due to the weather? How about the tidal variation in the barometric pressure? If GPS altitudes are off by hundreds of feet, then how far off is this phone going to be if I calibrate it in the morning but a low front moves in while I am hiking?

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I guess barometer is the latest!

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Knowing your position by the GPS , maybe it should be posible to automatic update local pressure from the nearest wx station or airport and feed it into the phone ( QNH pressure setting would give you your exact altitude , I think). Apps creators start working !

The more Google Phones are like "Star Trek Tricorders," the more likely I will buy one. Knowing Google Phones, they will also have all kinds of telemetry with servers and other sensor arrays, so all the Google Phones connected in the world would serve as a giant sensor grid monitoring everything on this planet. Wait. Is that a good thing?

Add a temperature sensor. Then build an app to measure and report creature comfort while traveling, especially on flights sitting on the tarmac without cooling.

There are various kind of altimeter, an airplane instrument called “altimeter” uses some kind/type of barometer to calculate its altitude. I am also a pilot and I tell you to accurately tell your altitude you will set your altimeter’s “aneroid barometer” (old plane instrument use this) you do this so that you will know if you will reach ZERO altitude. Let’s say you are on a beach swimming obviously you are on a zero altitude, but if you are on a mountain then you are no longer on a zero altitude, what if you are driving on a mountain and your instrument tells you that you are on an altitude of 10,000 (altitude of the mountain). To solve this you would need to set your barometer inside the altimeter to 10,000 feet so that your instrument will tell you that you are on a zero altitude even though you are 10,000 feet.

I think that is what that barometer is for.

Modified* (various kind of Altimeter -> Barometer)

There are various kind of barometer, an airplane instrument called “altimeter” uses some kind/type of barometer to calculate its altitude. I am also a pilot and I tell you to accurately tell your altitude you will set your altimeter’s “aneroid barometer” (old plane instrument use this) you do this so that you will know if you will reach ZERO altitude. Let’s say you are on a beach swimming obviously you are on a zero altitude, but if you are on a mountain then you are no longer on a zero altitude, what if you are driving on a mountain and your instrument tells you that you are on an altitude of 10,000 (altitude of the mountain). To solve this you would need to set your barometer inside the altimeter to 10,000 feet so that your instrument will tell you that you are on a zero altitude even though you are 10,000 feet.

I think that is what that barometer is for.

Altitude can be determined based on the measurement of atmospheric pressure. The greater the altitude the lower the pressure. When a barometer is supplied with a nonlinear calibration so as to indicate altitude, the instrument is called a pressure altimeter or barometric altimeter

XCSoar a free flying app (truelky free if you download from their homepage and NOT from app store) , already runs on Andriod & is crying out for a phone like this, we just need the Galaxy Note to get ICS OS then we may just reach heaven !!!!

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