

PressureNet collects 120,000 atmosphere data points per day from Android phones - cryptoz
http://pressurenet.cumulonimbus.ca/

======
cryptoz
This is my open source app that has grown massively recently. We're using the
barometers in some new Android phones to build a global weather network of
hopefully unprecedented scale. We just launched version 3.0 this week which is
livestreaming our data to an atmospheric science researcher at University of
Washington. Our primary goal is to grow the network and use the data to
improve short-term weather forecasting methods.

Edit: We are featured in MIT Technology Review right now:
[http://www.technologyreview.com/news/510626/app-feeds-
scient...](http://www.technologyreview.com/news/510626/app-feeds-scientists-
atmospheric-data-from-thousands-of-smartphones/)

And here's our 3.0 launch blog post with more information:
[http://www.cumulonimbus.ca/pressurenet-3-0-sharing-
visualiza...](http://www.cumulonimbus.ca/pressurenet-3-0-sharing-
visualization-research/)

~~~
breckinloggins
This is absolutely awesome!

I really love the idea of crowdsourced meteorological data. I can envision a
world where _every_ smartphone has a lower power barometer and ambient
temperature and humidity sensors. Combine this with lower power GPS and you
could have the majority of the world's citizens constantly transmitting basic
atmospheric data 24/7. As sensors become more advanced and cheaper, one can
even envision a time when smartphones also include things like air quality
sensors and so forth.

I can't imagine how accurate our weather forecasting would become if we had
constant access to this incredible amount of real-time data.

~~~
seles
I don't think ambient temperature and humidity sensors would work very well
because people usually aren't outside and when they are, phone is usually in
pocket.

I love this idea too though. I'm guessing pressure is one of the least
effected by being inside or in a pocket, while still being highly useful for
weather prediction.

~~~
fleitz
Individually you're right, in aggregate I'd expect the data to be very
accurate.

~~~
btown
The problem is that the effect of being in a pocket is not zero-biased when it
comes to temperature (and possibly also humidity). You'd see temperatures
being pulled towards normal body temperature on average.

~~~
fleitz
Yes, but in my rudimentary understanding of weather the importance is the
pressure differential rather than the absolute pressure.

I believe the data in aggregate will provide a pretty good map of the pressure
gradient which could then be fixed to the more accurate dedicated weather
stations. Think of it like the 10,000 year clock which uses a clock known to
drift in conjunction with a solar time fix to calibrate.

~~~
nieve
You may be right about pressure, but btown is talking about temperature and
that's going to have much worse systematic bias exactly as he says. Your
comment and his are nearly completely unrelated.

------
ChuckMcM
This is one of those things that really highlights the disruptive power of
ubiquitous computing + sensors. I expect to see more of it in the future.

I wonder if we could get Randall Munroe to do a "What if" treatment of a
million people taking a picture at the same time with their camera phones
pointed toward Sirius. Given EXIF data of time and GPS location, could you use
that data set to create high resolution images of astronomical entitites? If
they were all 5Mp cameras and you had a million participants, that is a
5terapixel image with an image surface across thousands of miles.

~~~
kintamanimatt
This is a really interesting idea. I believe, however, in this form it
wouldn't quite work as expected. What you'd end up with is five terapixels of
data, but not a 5TP image. The way you'd get that 5TP picture is to arrange
all those sensors in a grid and focus the image of your desired object onto
that grid. In this form you'd end up with a very, very high resolution image
because only a tiny fraction of the image would be falling on each sensor.
Each fraction of the total image could then be combined into one mega image,
and voila, your 5TP image!

If you have a million people all focusing their 5MP cameras at the same
object, you'd end up with a million photos of the same object, but without
anything more than 5MP because the entire image would fall on each sensor.

Perhaps people should donate their old phones to science and equivalent
sensors could be arranged into a giant grid with a powerful lens attached. The
only difficulty then would be atmospheric distortion, so perhaps a cheap trip
out of our atmosphere would be in order! I propose we call it the Hacker
Telescope.

~~~
ChuckMcM
Well outside the atmosphere we've already got a plan, its called the James
Webb Telescope [1] :-)

One of the weird things about light is that the photons that hit the camera
sensor in California are not the same photons that hit the camera sensor in
New York. So you could, if you chose to, add the two pictures together which
would increase its brightness (more photons) and not change the content of the
picture. The trick of course is figuring out which pixels in the camera sensor
were getting the same (or nearly the same) photons.

Since you are taking a picture of the stars, which are far enough away that
parallax effects won't change their relative position, I should be possible to
map the position of the stars in each image, combine it with the pointing
vector from the accelerometer, to then create a projection matrix that would
allow you to back project the camera pixels into an idealized focal geometric
plane.

Now you have a map of all of the various image pixels with respect to their
projection onto this plane, and you can then add together like pixels. Or
generate a pseudo 5mP image where each pixel is comprised of a million sub-
samples. (sometimes I wish I could draw in this editor)

[1] <http://en.wikipedia.org/wiki/James_webb_telescope>

~~~
kintamanimatt
One hitch might be the precision of the sensors (accelerometers, etc) in the
phones might not be sufficient to make this work!

I'm all for tearing down a million old phones, removing the sensors, and
blasting many "micro" telescopes into space!

------
taylorbuley
I've really enjoyed watching this app grow over the years and its storyline
develop

I remember when it launched here after a weekend of hacking when the first
barometric sensors came out

Edit: it looks like they did "Show HN" almost a dozen times so perhaps my
first glimpse wasn't as special as I remember it being.
[http://www.hnsearch.com/search#request/submissions&q=pre...](http://www.hnsearch.com/search#request/submissions&q=pressurenet&start=10)

------
jonstjohn
I love this project and the idea of linking together the sensors on so many
devices. I wonder if something similar could be used for earthquake detection
using motion sensors in the phone, since many phone rest on flat surfaces at
least part of the day (most of the day for me). It could be activated when
phones are resting on a flat surface with no movement.

~~~
CanSpice
The Quake-Catcher Network (<http://qcn.stanford.edu/>) has been doing this for
years with laptops and USB motion detection modules. They say that laptops are
less than ideal because in larger earthquake laptops bounce around and give
less accurate results. Mobile phones would suffer even more from this.

I used to have QCN on my laptop (old MacBook) and the sensors were quite
sensitive, to the point where it could detect footsteps a couple of feet away.

------
rdl
Presumably this will matter more in places like Africa, India, etc. which lack
the same level of highly developed weather forecasting sensors as the US. It
seems likely low-end Android phones could be just as pervasive there at some
point, and would make a huge difference to farmers, public safety, travel,
etc.

I'm not sure how you go from here to there.

~~~
philjones
At the moment, only the newer, high-end Android devices have barometers in
them. A regularly available data or wifi connection is also necessary for the
data to be real-time. So, this should work just fine right now in the major
cities of India and the more developed countries of Africa, but for the most
part it's probably a bust. Their lack of one infrastructure mirrors another.

------
zachlipton
Very neat technology, and I think it could be of value in the developing world
and sparsely populated areas, but is there that much need for this data in
many parts of, say, the US or Europe? Here in San Francisco, I've got highly
accurate weather stations at SFO and OAK, plus dozens of other stations on
Weather Underground around the city. The variability of these readings over,
say, 10 miles is quite low. Are there specific ways in which a more dense grid
of barometric pressure measurements can give us further insight into weather
patterns?

This would be a great augment in areas where the density of observations
stations is much lower. Wind speed, which does vary a lot more due to terrain
and structures, would be neat to map this way, but it's hard to measure the
wind through our pockets on cell phones.

------
mynegation
I am planning to assemble a barometer (and ultimately gather temperature and
humidity data as well) on Arduino, and upload data feed to my computer. Does
PressureNet have an API to accept data from devices other than Android phones?

~~~
cryptoz
Almost. I'm working on this as almost top-priority right now. There are two
APIs/SDKs that I'm building for pressureNET this week. The first is a
customer-facing API to access the livestream data, and this is what we have in
Beta right now streaming just to Cliff Mass. We'll finish that up in a few
days, and move on to API number 2, which is what you're asking for. My first
step is allowing other app developers to include pressureNET inside their
apps, in order to increase the value of both projects. I will follow this by
accepting data from other sources as well.

All of us who work on pressureNET are doing it in our free time as we all have
day jobs, and this project currently does not generate any revenue. So you may
wait a little while for the second part of that second API to get done. But on
the other hand, we're open source, so if you're itching to get it ready you
can help us out. :) The project is split into three repos on GitHub, we're
going to merge the two servers into one sometime soon.

<https://github.com/JacobSheehy/pressureNET>

<https://github.com/JacobSheehy/pressureNETServer>

<https://github.com/JacobSheehy/pressureNETAnalysis>

------
jug6ernaut
Really awesome app/idea. I have been waiting for someone to do this. One
suggestion, create hourly(or w/e increment would work best) maps(heatmap esk)
of this data.

I understand this is (probably) meant as a scientific tool for data retrieval
but adding something like this would give a lot to the users of how the data
is being used and what it actually means in comparison to everyone else.

Great work tho!

~~~
philjones
An isobar display instead of individual info points has been a goal in
pressureNET for a long time. Giving the user enticing visual feedback is part
of making the app more broadly appealing.

~~~
jug6ernaut
Glad to hear it. I did some work in this but plotting PM & Ozone data on an
android device, I had never done anything remotely similar before and had a
hard time finding any good options besides going out and writing my own
charting system. I ended up using a heatmap style plotting system. Looked good
but it was very hard to get the colors to match up to any particular scale. I
hope you end u with better results then i did :).

[https://www.dropbox.com/s/7jvx3iboil7noaw/2012-04-04%2014.41...](https://www.dropbox.com/s/7jvx3iboil7noaw/2012-04-04%2014.41.02.png)

~~~
philjones
Ooh pretty.

We don't necessarily need to match up to colours if we're going strictly with
isobars. Though a heatmap style, again, would be great looking.

------
caf
What's the intended purpose behind including barometers in newer phones?

~~~
cryptoz
Some Google employees have mentioned that it's there to improve GPS times. The
devices already have a latitude+longitude estimate from cell towers and WiFi,
and the barometer adds an altitude estimate.

~~~
caf
You would have thought that "ground level" (based on the latitude and
longitude estimate) would be a pretty good starting estimate for altitude in
most cases.

~~~
cskau
In a modern urban environment I think this is becoming less and less so.

Living in a metropolitan area for me at least mean I spend quite a lot of my
time in an Nth floor apartment, Mth floor office, and commute by subterranean
subways and elevated train tracks, walkways and highways.

~~~
caf
The difference in altitude between the subway and the top floor of an
apartment building isn't really very far though, when observed from a GPS
satellite that's 20,000 km above you.

------
cskau
Trying the app I saw there's an option choosing who you want to share your
data with. I'm inclined to choose 'public' but in the end lack of insight into
whether and/or how you do data anonymization made me chose otherwise.

Care to elaborate a bit on how and what you do with the data?

~~~
cryptoz
Excellent question. I do realize that our sharing options are a bit vague, and
I'm going to write up official descriptions and examples to eliminate all the
confusion. We have not taken any action on the 'Public' option yet, so for now
that option is equivalent to 'Us, Researchers and Forecasters'. There is
currently no anonymization done as our only customer so far (Cliff Mass)
requires the full dataset for calibration. For the Public data set, we will
look into how to deal with this - it should probably not include unique
identifiers, and so we'll likely remove those. This does, however, remove some
of the utility of the dataset, so perhaps there is another option.

I'll make sure to be more open and clear about this as we make the decisions.
Thanks for your comment.

------
grzaks
Nice project. Can you elaborate more on your plans how to achieve the
necessary scale? How do you drive traffic and installs to the app?

~~~
cryptoz
Thanks. Yes, we have some very clear plans on how to grow. This was a big
problem for us about a year ago, when our only method of growth was by posting
to r/android and r/xoom. Currently, the project has solved the original
chicken-and-egg problem in that we already have enough users that our existing
userbase provides enough content to be interesting to new users.

We have a new method of very large growth coming up, though. There have been
at least four different app developers that have contacted us recently, asking
if they could include pressureNET inside their own apps. These are typically
very popular apps with 1,000,000+ installs. Now, most of these users don't
have barometers, but even 1% would be very large growth for this project. So
there's that. This requires me to build a simple pressureNET SDK, which is a
priority for this weekend.

Beyond this short-term, large growth, we have another plan which is to contact
local Samsung and carrier offices and hopefully work towards a goal of having
pressureNET included in next-generation phones. Contacting Google is a very
clear long-term goal, but I want to grow with my current opportunities a bit
more first.

~~~
grzaks
Congrats on reaching critical mass already!

I wonder about those 3rd party developers: what's the incentive for them to
include pressureNET in their apps?

------
nivertech
@cryptoz, can you give us a raw format for livestream data?

Thanks

~~~
cryptoz
Yes, definitely. I'm working on it right now, actually. We're building an API
that Cliff Mass is using right now, so everything is in place and working. I
have to finish some features in code, document everything, ensure there are no
privacy breaches, and then we'll go live with it. I'll keep you updated.

