1
It measures
The barometer logs in the background. You don't have to do anything.
Prototype — not yet in the App Store
Your iPhone has
Your iPhone has
a barometer.
It's more sensitive than the weather station behind your forecast — and it sits in your pocket around the clock. Aneroid logs air pressure and keeps asking how you feel. After a few weeks it knows your threshold and your delay. Not a generic one.
How it works
2
It waits
If there's a shift over three hours, it asks 45 minutes later — because you don't feel it at the same time.
3
It asks blind
Three times a day it also asks without any trigger. That's the control group.
4
It answers
Is there a connection for you? Which way does it go, and how fast?
There's no diary, no trigger list, no medication log, no food correlation. There are tens of thousands of log-your-symptoms apps, and they're tedious, because they ask for too much. The check-in is one tap. It has to work in the middle of an attack.
Most apps have already decided what you feel
Falling pressure, for everyone
Alerts built on what the literature says about the average: symptoms follow falling pressure. That's right for many — and wrong for those it doesn't apply to. An alert app never arrives at the conclusion that there's no connection for you specifically.
Your direction, your threshold
Aneroid assumes nothing. It measures, asks, and compares with the control group. If your symptoms get worse when pressure rises, it finds that. And because it asks without any trigger, it can reach the answer no other app gives: there's no connection for you.
“It doesn't warn when pressure is heading UP. That's where my symptoms start.” Reviewer of a competing barometer app
Privacy
There's no server to send your data to
- Everything stays with you. No account with me, no server I can read. The measurements and your answers live on the phone and in your own private iCloud — so they survive the phone getting lost.
- No tracking, no adverts, no third-party SDKs. There are no analytics tools in the app at all.
- Location is required — and stays on the phone. One hPa is roughly 8.3 metres. Without knowing how high up the phone is, it measures your floor as much as the weather. The conversion happens on the device.
- Weather is optional, and off by default. It's the only place anything leaves the phone: turn it on, and your approximate location is sent to Apple's weather service to fetch temperature and humidity.
- You can take your data with you. Everything can be exported as CSV, and you decide who the file is shared with. Want it gone, delete it in your iCloud.
It's not finished
Aneroid is a prototype under development and can't be downloaded yet. The question it's built to answer first isn't whether the hypothesis holds — it's whether an iPhone can even collect enough measurements in the background to investigate it at all. That takes a week of real data to know.
Why does it require my location?
Because a pressure reading without altitude means nothing. One hPa is roughly 8.3 metres, so the same phone shows differently on the ground floor and on the fourth floor — and two phones in the same city can differ by several hPa on terrain alone. Altitude is calculated on the phone from pressure, GPS and terrain maps. It's never sent anywhere.
Can it warn about migraine?
Not yet, and maybe never for you. Aneroid starts by finding out whether there's a connection for you at all, and which way it goes. A warning without that basis is a guess with nice typography.
Does it work on iPad or in the simulator?
No. It needs a real barometer, and that's in the iPhone.
What about the three times a day it asks for no reason?
That's the whole point. Without them you can't tell “I feel bad after a pressure change” from “I just feel bad”. They can be turned off, but then the app can't answer its own question.
What do we actually know?
Forty-five articles about air pressure, the body and how it's measured. What the research has found, how big it is — and where it stops knowing anything.
The feeling
The 18 patients who were wrong
Seventeen of eighteen were certain the weather controlled their arthritis. Fifteen months of measurements said otherwise. The study is from 1996 and is still uncomfortable.
The bodyYou have a barometer in your head
The inner ear doesn't just measure which way is up. New experiments suggest it also registers what air pressure is doing.
Pressure and headaches336,951 hours of headache
4,375 Japanese people logged their headaches hour by hour for a whole year. What the machine found in the data wasn't what people believed.
Do you react to the weather?
Get in touch if you'd like to try it once there's something to try — or if you think the premise is wrong.
hej@jegerlars.dk