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Topic: Looking for sketch for the BMP085 arduino (Read 1 time) previous topic - next topic


Just got my BMP085 board. I am looking for a sketch that prints temperature in farenheit and pressure in milibars.
If any out there would appreciate a link.


[ I won't respond to messages, use the forum please ]


Here you have also more information about to wire and to program the arduino to read this sensor:




Thanks for all the replies. I will have to write some code to convert pressure pa to inches mercury and convert C to farenheit, just have to decide where to put it at in the program, because it has to read the temp before it can produce pressure reading.


I'd put those conversions just before outputting to whatever wants such non-SI units.  (OK so degC isn't SI but its closer than degF)

Note in particular that inches of mercury is not accurate unless you compensate for local gravity and the temperature, but perhaps you are assuming standard values for these.
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Jan 18, 2012, 02:41 pm Last Edit: Jan 18, 2012, 02:43 pm by serbcccc3 Reason: 1
So im a fairly new to everything and lastnight I also was looking for a basic sketch to read my BMP085.  I used the below code (see link) which is the same code mentioned in this post and it compiled without error so I uploaded it to my Arduino Pro 5v and the serial monitor did not return any information at all...it just stayed blank.  Not even the Serial.print in the code was displayed.

So my question is i guess is there something I am missing here?  I have detailed exactly what I did below.  If anyone can help i would GREATLY appreciate it as i almost pulled my hair out last night trying to figure this out!

Arduino Pro 5v
bmp085 breakout board from Sparkfun
Logic level Converter from sparkfun
- i literally copied the code from that link into a new sketch and compiled and uploaded... the data leds on my FTDI were flashing and I know it uploaded the code (i also tested uploading some other code just to ensure i didnt have an upload issue). http://bildr.org/2011/06/bmp085-arduino/

The circuit was connected up as follows (see attached image).
Am i doing something wrong here with the actual connection to the board?  (please note that the 3.3v on the arduino pro where the wire is connected is 5v on my arduino, i just copied the picture from sparkfun).

Thanks for any advice.


Hi !

I think there is something wrong on your picture serbcccc3 ! Wiring is correct on the Arduino side (if the pin 3V3 on the picture is in fact the 5 V on your board) but you have to put a 3V3 voltage on the pin "LV" (and GND also on the "LV" side) of the logic level converter (connected to the VCC of the sensor)

In your picture the sensor is in fact not powered ! Maybe it is the reason why you don't read any i2c data with the code you used !

I hope that my post will be usefull to you !
Bon sang ! mais c'est bien sur !


Ok, so if i understand you correctly, on the LLC i have to connect both a low voltage 3v3 and a the high voltage 5v (from arduino)?  I thought the LLC drops the voltage down for me?


Correct ! 8)

As it is explained on the sparkfun site : http://www.sparkfun.com/products/8745 and on the related schematics :
"The level converter is very easy to use. The board needs to be powered from the two voltages sources (high voltage and low voltage) that your system is using. High voltage (5V for example) to the 'HV' pin, low voltage (2.8V for example) to 'LV', and ground from the system to the 'GND' pin."

Hope that the code will work now ;)
Bon sang ! mais c'est bien sur !


Ok that makes COMPLETE sense now.... for some reason I thought the LLC would drop down the VOLTAGE too..... anyway, can i ask then if i have an arduino pro mini 5v, there is ONLY a 5v source from the board and i would have to dropdown the voltage somehow to power the LV on the LLC right?

Sorry im pretty new to everything and anything... but thanks for the help!


Yes you have to dropdown the 5V voltage to 3.3V ! you can use for example this kind of breadboard with a AA battery:

I didn't find any DC/DC converter boards adapted to your application (only high current converters) on Sparkfun site.

You can also use a voltage regulator (with adequate components around it) or power supply breakout boards proposed by Sparkfun.

Good luck, tell me if you find a solution.
Bon sang ! mais c'est bien sur !

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