Develop Bugs

Compas

Now i love my desire... Its fantastic but it isnt without some issues...
One ive noticed that could be a problem esp when your working with reality overlay apps...
The compass doesn’t seem to work that well...
Its slow to respond to movement and even when it does move its horridly inaccurate. north seems to have a room for error of 60-90 degrees.
Has anyone else noticed this? Is it the same for most digital compasses? or do i have a faulty module?

Hi Nutsy,
I've also noticed these issues with the compass in the Desire. I've worked with magnetic compass chips before and I think it's all to blame on the way these compasses work:
To sense the earth's magnetic field they use a two- or three axis magnetometer. Although it's a very accurate way to sense the earth's weak magnetic field, it's also very sensitive to any other magnetic field. That means that the presence of ferromagnetic materials (like iron) or electrical currents in the vicinity might really screw up your compass reading.
So electrical wires, iron piping, laundry machines (almost anything that you would find indoors that runs on electricity or contains iron), will interfere with your compass.
a good alternative would be to use a gyroscopic compass like they do on submarines, but I don't think these fairly expensive devices aren't used in mobile equipment yet. So the only thing to do is to stay away from anything that might interfere.
The slow response to movement might be caused by internal filtering. These analog sensors produce quite an amount of measurement noise. In order to cancel this, they probably use some sort of filtering algorithm like this one:
step 1 -> Take a new sensor reading.
step 2 -> Add it to a buffer that contains the last 25 readings.
step 3 -> Calculate the mean value of all measurements in this buffer. This will be the compass heading that is sent to Android OS or your application.
step 4 -> Repeat this cycle every 25 milliseconds.
Hope this answers your questions. Of course if you compass readings never make any sense under any circumstances, the thing might just be broken...
Friendly regards,
Joost
Ps.
There's an App in the market called "Metal detector" that actually uses the interference "problem" with the compass to detect ferromagnetic metals.

Wow Thanks for the really detailed reply...
Im glad its not just me then... Didnt really want to RMA it over a dodgy compass unit.
And thanks for letting me know about that app... sounds usful... I guess it could be used to detect wireing in plaster as well?

You're welcome.
In theory you could use it to detect metal or wires in a plaster wall. I've just tried it, and it works quite well. On the other hand, I really don't want to risk electrocution by trusting a telephone to find electrical wires...

My compass is shocking. Actually points closer to South whenever I open Compass or a programme which uses the compass like G-sky. I have to calibrate it every single time.
Thing that annoys me, is if I calibrate, then exit the programme and immediately re-open the programme, it doesn't remember the calibration, it reverts to pointing in a ridiculous direction.
I want to hit it with my fist.
Addtitionally, think it's broken?

jimmymagix said:
My compass is shocking. Actually points closer to South whenever I open Compass or a programme which uses the compass like G-sky. I have to calibrate it every single time.
Thing that annoys me, is if I calibrate, then exit the programme and immediately re-open the programme, it doesn't remember the calibration, it reverts to pointing in a ridiculous direction.
I want to hit it with my fist.
Addtitionally, think it's broken?
Click to expand...
Click to collapse
Yesterday I found out the same thing... Sometimes I cant even get it working after calibration. I was beginning to think that this happened because I dropped it once pretty hard. What should we do next? Can this be solved by replacement with warranty or something?

Smauglys said:
Yesterday I found out the same thing... Sometimes I cant even get it working after calibration. I was beginning to think that this happened because I dropped it once pretty hard. What should we do next? Can this be solved by replacement with warranty or something?
Click to expand...
Click to collapse
Make sure your phone isn't in a case which uses magnets to keep it closed, as they affect the compass. If you're affected, take your phone out of the case and try again. Also, try out in the open, away from structures which may contain a lot of ferrous metal.

In my case the problem is due to powered-on wi-fi module. Turning off wifi, compass works fine. Could Anyone elserepeat my experience?

poldie said:
Make sure your phone isn't in a case which uses magnets to keep it closed, as they affect the compass. If you're affected, take your phone out of the case and try again. Also, try out in the open, away from structures which may contain a lot of ferrous metal.
Click to expand...
Click to collapse
Yes I know that. Tried out doors, and wheres no metal... When I had the G1, the compass worked normally.
In my case the problem is due to powered-on wi-fi module. Turning off wifi, compass works fine. Could Anyone elserepeat my experience?
Click to expand...
Click to collapse
Just tried what you said. It did not help for me. I turned it of completely.

Smauglys said:
Yes I know that. Tried out doors, and wheres no metal... When I had the G1, the compass worked normally.
Just tried what you said. It did not help for me. I turned it of completely.
Click to expand...
Click to collapse
Just went outside to test it again. And I think I found how to get it working. If i launch the compass application, and try to turn the phone in the flat position (on its back), then the arrow moves in random directions. But if i lift the phone that it is facing straight to my face, and then turn left and right a few times, like a steering wheel, the compass "calibrates" as I can see. And then when I lay it down again flat, it starts to work normally. Can anyone try this, if you understood my instructions?

A more accurate way of calibrating the compass is by rotating the phone twice around each axis, ideally you should do this away from anything metallic or any interfering magnetic fields preferably outside.

Er......
Where is the compass?
I dont seem to have a compass! In my list of apps there just isnt one called compass...

The Analogue Compass app is very buggy for me so I use the Compass app -> http://www.androlib.com/android.application.com-apksoftware-compass-qAC.aspx
When taking readings, I;
Always have to recalibrate on startup as far too many objects cause large interferences within the sensor making it go astray, even the charging cable causes it to go berzerk. The known working routine is to calibrate by fast twisting and turning the phone [I do it after running the built-in figure 8 calibration routine]
Keep it mid-upper body height with no metals nearby (jewellery/belt/metallic objects minimum >5ft away), holding still and level across the x-axis
Point the upper-end of the phone in the direction I want the bearing of (this depends on the type you use though, I use the digital type)
I spin the phone around and then retake 2 more readings for a total of 3 readings - averaging them out for a final mean reading
I only have 2 directions calibrated through professional consultation when this room extension was built a few years back and know the rough directions all sides this property faces, but in particular, I'm 100% sure of the exact degree reading one wall faces. This app using the built-in compass sensor reads that bearing spot on everytime after calibration (fluctuation is 1-2 degree max).

Some friends in a Lithuanian Android forum, suggested to do this, like it is shown in the video. Works perfectly every time. And I thought that something was wrong, because I never had to do anything like this on my G1.
Youtube video ID, because I cant add link because of spam protection http://www.youtube.com/watch?v=sP3d00Hr14o

[Q] Location settings, use sensors?

Looking in location settings and there are three options. Use wireless network, use gps, and use sensors. Ive never seen the "use sensors" option before? Im assuming for best gps performance is to have all three checked?

I'm interested to know this as well...
Sent from my SPH-D710 using XDA App

Well the description that pops up when you check it elaborates pretty well. From what I gathered, it's mainly meant to be used as a battery saver when you're using the GPS walking around, especially indoors. What I think it's doing is using things such as the accelerometer and compass to aid the GPS in determining the direction and speed that you're moving in, thus meaning the GPS doesn't need to actively search for your signal as hard, which would drain your battery when that signal is weak (I.e, indoors).
What really excites me about this feature is not the battery savings,but the potential that the gps might now finally be able to keep a lock in an urban downtown. I live in , so the mountains combined with the buildings means that once I set foot downtown my gps is next to useless. This new feature seems to have the capability to eliminate that.
Plus, it might result in overall accuracy improvement in any generic gps scenario.
Sent from my SPH-D700 using xda premium

Im sure sensors mean accelerometer/gyroscope for navigation while driving? Like when you hit the brakes, accelerate, turn, etc. seems cool
Edit: and what squshy said lol

Coming from an Evo 4G and only used Google Navigation once in my car so far. I enabled the sensors for GPS when it prompted, and I noticed the tracking was off when the car was stopped, mainly at an intersection.
It showed me moving back and forth on the road, enough that it showed crossing the intersection, and twice it showed me turning. Again this was all while still but I was holding the phone when looking.
So maybe by sensor they mean the motion sensors and the slight movements were putting it off? I'll be using it again today and I'll try with the sensors for GPS disabled.
And just to add, overall the GPS still worked in terms of getting me where I needed to go, just haven't seen that kind of tracking jitter from the Evo.

conscio said:
Coming from an Evo 4G and only used Google Navigation once in my car so far. I enabled the sensors for GPS when it prompted, and I noticed the tracking was off when the car was stopped, mainly at an intersection.
It showed me moving back and forth on the road, enough that it showed crossing the intersection, and twice it showed me turning. Again this was all while still but I was holding the phone when looking.
So maybe by sensor they mean the motion sensors and the slight movements were putting it off? I'll be using it again today and I'll try with the sensors for GPS disabled.
And just to add, overall the GPS still worked in terms of getting me where I needed to go, just haven't seen that kind of tracking jitter from the Evo.
Click to expand...
Click to collapse
Interesting. Looking forward to your results with the setting off.
---------- Post added at 09:57 AM ---------- Previous post was at 09:56 AM ----------
squshy 7 said:
Well the description that pops up when you check it elaborates pretty well. From what I gathered, it's mainly meant to be used as a battery saver when you're using the GPS walking around, especially indoors. What I think it's doing is using things such as the accelerometer and compass to aid the GPS in determining the direction and speed that you're moving in, thus meaning the GPS doesn't need to actively search for your signal as hard, which would drain your battery when that signal is weak (I.e, indoors).
What really excites me about this feature is not the battery savings,but the potential that the gps might now finally be able to keep a lock in an urban downtown. I live in pittsburgh, so the mountains combined with the buildings means that once I set foot downtown my gps is next to useless. This new feature seems to have the capability to eliminate that.
Plus, it might result in overall accuracy improvement in any generic gps scenario.
Sent from my SPH-D700 using xda premium
Click to expand...
Click to collapse
I get the description but im curious if this is a setting we should leave on all the time or if it is better used for specific uses.

Haven't driven yet but did bit of Googling. I'm conditioning the battery, bored waiting for it to charge fully, lol.
squshy 7 has it in that it's the gyro motion sensors. A few other Samsung phones with the feature say that's it's meant for pedestrian navigation and urban areas where it's having a trouble tracking enough satellites.
Samsung's docs didn't say anything about disabling it outside those scenarios, but there are some forum posts regarding GPS stability issues and people seemed to have better results when they disabled sensor aiding for driving.
Some users mentioned that calibrating the gyro motion sensors and the compass helped. One Samsung user guide said to keep the phone flat and pointing in the direction you're moving and to avoid any magnetic fields.
So still testing it later while driving, also going to try both on and off while doing walking navigation. I'm in downtown LA so I'll be able to test the urban effect.
There's a good sized thread on the Galaxy S II forums about gps issues. Skimming around it looks like it's split between people saying GPS is fine and otherwise.

conscio said:
Haven't driven yet but did bit of Googling. I'm conditioning the battery, bored waiting for it to charge fully, lol.
squshy 7 has it in that it's the gyro motion sensors. A few other Samsung phones with the feature say that's it's meant for pedestrian navigation and urban areas where it's having a trouble tracking enough satellites.
Samsung's docs didn't say anything about disabling it outside those scenarios, but there are some forum posts regarding GPS stability issues and people seemed to have better results when they disabled sensor aiding for driving.
Some users mentioned that calibrating the gyro motion sensors and the compass helped. One Samsung user guide said to keep the phone flat and pointing in the direction you're moving and to avoid any magnetic fields.
So still testing it later while driving, also going to try both on and off while doing walking navigation. I'm in downtown LA so I'll be able to test the urban effect.
There's a good sized thread on the Galaxy S II forums about gps issues. Skimming around it looks like it's split between people saying GPS is fine and otherwise.
Click to expand...
Click to collapse
Good info. Since i live in a rural area i may just disable it for now.

GPS can not be set correctly

So now I have the Nexus 4 days and not really angers me that my compass really works 100%.
I have him with various calibrated compass apps already but something does not seem to agree there.
If I slowly turn my phone on its own axis, the compass rotates too slowly mit.Nur he moves to something.
And then when I get on a given compass direction (in my case, between West and South) moves to the cell phone is faster and then briefly right times.
I think the cell phone in the south it is really as it should, I think the North it is actually there, according to compass the west.
What can I do and how it looks at you with the compass.Can I put him somewhere completely to zero?
Ask for your help ....

Can someone help me with my problem?

Moved to Q&A
When you're using your compass make sure there are no large metallic objects or anything magnetic any where near it. The Earth's magnetic field is very weak and can be covered/jammed easily.

[Q] Barometer calibration?

Just got the GN for Sprint 2 days ago and have so far enjoyed my selection. I have run across an issue with the onboard barometer though. It seems to always read way lower that the pressure actually is. With every app I use it on it reads 1.2 mercuries low inHg and about 35 hPa low depending on which app I use. Is there any way to calibrate the sensor to compensate since not all apps have a calibration option?

Zero responses? There has to be some way to calibrate it since it uses a piezo system and not actual mercury.

Depends on where you are. It's not corrected for height, so if you are 1000ft above MSL, you'll read 1 inHg low because that's the actual pressure. Your local weather station/airport altimeter setting have corrected for altitude, so places like Denver, CO don't scare people by telling them the local pressure is lower than at the center of hurricanes.
Various apps have a built-in correction factor that you have to manually enter. Barometer HD and Barograph are two that I've found so far that have a correction setting. You have to play with it until it reads the same as the weather man says. Barograph seems cool because it periodically takes the reading, instead of telling you what it is every half a second. You only see the power of a barometer by observing the pressure changes over several hours. Another graph over time app I just found is Barometer Monitor. There's no correction factor, but it does allow you to specify how often it measures the pressure.

Barometer, and temperature

Whoa, I didn't know our phones did this. How cool!

Yeah it definitely has it, but it's not advertised because of how woefully inaccurate it actually is.

Didn't know that either, thanks!

Actually mine works fine. Temperature is withing 1 degree as long as I don't use my phone much, so it doesn't heat up skewing the results, barometer also seems fine, the couple times I checked at airports or from weather channel and adjusting for altitude, it was within couple mbars. At least with barometer, you can adjust it to correct value, if the error is big, where with temperature the main issue would be to keep the phone at ambient, so don't get surprised at error if you kept it in your pocket, or played game. There is also humidity sensor and I was shocked when it showed 100% humidity on a foggy evening, as it should, so that seems to be working fine as well.

I haven't had similar experiences with mine, although perhaps not using the phone could provide slightly more accurate readings. I live in a pretty humid area and have found even on the most humid of days it doesn't register properly.

You must have newer hardware -- I don't think either my 900T or 900V have humidity and air pressure sensors.
Frank

I found a sweet app called Thermometer Plus. The reason I like it is mainly the selection of semi-transparent widgets (displaying different sensors). I have the one with temp and humidity (set to update every 5 mins I think) on my main home screen so I use that to adjust my AC, etc. accordingly, mainly to keep humidity in a reasonable range.
Galaxy Sensors is also cool to see all of the device's sensors. It also has a widget, but it only displays the temp.

Frank Westlake said:
You must have newer hardware -- I don't think either my 900T or 900V have humidity and air pressure sensors.
Frank
Click to expand...
Click to collapse
I bought mine in November so it's not that new, I think all N3 have it, but they don't show normally.
If you check Antutu benchmark under hardware, it should show all sensors.
Androsensor program will show all sensors readings, or type *#0*# on stock dialer, then click sensor, should show all the hardware and if it's working.

Pete is correct, all variants have it.