ADAFruit BMP085 libraries

Projects Programming
1

HI, i'm trying to get the ada fruit bmp085 sensor libraries to work and i keep getting and error even if i follow the instructions exactly.

i've installed the sensor and bmp085 library as instructed but i get this error on compile

In file included from sketch_jul03a.cpp:2:
C:\arduino-1.0.1\libraries\Sensor/Adafruit_Sensor.h:13: error: stray '\302' in program
C:\arduino-1.0.1\libraries\Sensor/Adafruit_Sensor.h:13: error: stray '\267' in program

so obviously the issue is with the sensor library? i can see i'm not the only one having problems with this.

2

Those lines appear to be in the comments block

What platform are you running on? e.g. linux or Mac etc?

I suspect this is some sort of file format issue in the translation of newlines and returns to whatever platform you are using

3

Google stray '\302'

4

i'm on windows 7 arduino 1.0.5 ide

5

ok i figured it out - never right click and download files off github. always use the download zip option.

so now it's running, however the altitude is wrong, i'm 30 metres from sea level not -12. if anyone has played around with this it'd appreciate some pointers.

6

so now it's running, however the altitude is wrong, i'm 30 metres from sea level not -12. if anyone has played around with this it'd appreciate some pointers.

I'd seggest reading some Douglass Adams books. Adding 42 to the reading you get would solve your problem. After all, its the answer to life, universe, and everything.

Or perhaps you need to post a schematic and some code.

7

A barometric pressure sensor doesn't measure altitude, it measures atmospheric pressure.

You can calculate your altitude if you know the barometric pressure at your location.

Look at the raw data from the device, i.e the atmospheric pressure and compare it with the value given by your local weather forecast provider. This will determine whether the device is working correctly.

From what I've read, these devices are supposed to be calibrated in the factory and are accurate to a typical absolute error or +/- 1, however max absolute pressure error can be a lot higher (according to the spec), I think it can be +/- 2 or 3

So you may need to include some calibration in your software to correct for the absolute error in the measurements from the device

8

What he said,

Barometric pressure sensors, used to estimate altitude, are good for determining the relative altitude difference over short periods of time ( as long as the weather doesn't change ).

For absolute altitude determination, they are not very useful, unless calibrated against a precise measurement of current local atmospheric pressure and known reference altitude. You can usually find the pressure in real time from your nearest airport or weather service office, because it is important for calibrating altitude meters in commercial aircraft. You also need to understand their complicated and tricky methodology for pretending the airport is at sea level.