💬 Atmospheric Pressure Sensor

[ghislain]

Where did you buy your bmp180 ? you said the 3 you have make the same behavior ? something is wrong with the BMP sensor.

[James Flosse]

I bought it in banggood, but it work's before...

[ghislain]

It worked for a while and now it doesn't ? no problem of power supply ? 3v3 ?

[James Flosse]

I supply itwith the 3.3 V output off arduino

[ghislain]

I supply it with 5v, are you sure it's a 3v3 version ?

[James Flosse]

i tested with 3.3V and 5volt but same result
http://www.banggood.com/fr/GY-68-BMP180-Digital-Barometric-Pressure-Sensor-Board-Module-p-1059025.html?rmmds=myorder

[ghislain]

OK, i've no further idea to help you. But i think your sensor is dead. DId you try older or newer library to compile your project ?

[James Flosse]

Have you link for older library? Are you french?

[ghislain]

I am and you ? I can give you the sketch which is working for me with library i used.

[James Flosse]

Yes ^^ . can you give me at snyp_thx at hotmail dot fr?

[bgunnarb]

Hi!
I had exactly the same problem until I realised I had compiled for the 8 MHz version of the Arduino Pro Mini instead of the 16 MHz version.
Also, recently building an humidity sensor I realised there are no pull-up resistors on the SDA SDL lines, but that should be built-in if you use a break-out module.

[Heinz]

Which altitude did you enter, or at which sealevel do you live (in meters)?

const float ALTITUDE = 688; // <-- adapt this value to your own location's altitude.

The pressure of 728 hPa is a bit strange as it should be around 1000 hPa. In my eyes you threw out the code to correct the pressure depending on the sealevel of your home. See the code from my sketch:

float pressure = bmp.seaLevelForAltitude(SEALEVEL, absolutePressure);

Here you can download the sketch I am using:
https://github.com/windkh/mysensors/blob/master/WeatherStationSensor/WeatherStationSensor.ino

The forecast will be unknown for at least 30minutes, because the sensor needs that time to detect a weather trend.

[James Flosse]

@bgunnarb you are find the problem, i think i have arduino pro mini 3.3V but it's 5V. Thx very much it's work better now :)

[Jeff Willecke]

Where do the pin assignments live?

[gohan]

@Jeff-Willecke
in the article page
SCL A5 (analog input) Marked blue
SDA A4 (analog input) Marked green

[Jeff Willecke]

@gohan it appears as though I need SLC and SDA for the sensor it will prevent me from using a second SLC/SDA device. I was assuming that they were utilizing the analog input. My comment may be deleted as it is clearly not applicable

[gohan]

that is I2C bus, you can collect multiple devices as long as they have different addresses

[Jeff Willecke]

OH cool. I guess I have tons more to learn thank you for your help

[skywatch]

The initial description on this page refers to BMP085.
The 'Example' states it is for BMP085 with Adafruit library (linked for dowbload).
The sketch uses a BME280 with library from Embedded Adventures.
The Datasheet is linked for a BMP085.
The shopping guide links to a BMP180.

????

[mfalkvidd]

Sorry for not noticing your post earlier @skywatch

The example was originally designed for BMP085. When the BMP180 became widely available, the buy link was updated to the newer version with the note "replaces the old BMP085". Both use the same library.

At a later stage, a MySensors user suggested changes to the example sketch to use the BME sensor instead. I don't know why this change was made, but my guess is that the user liked the BME sensor better. I don't know why the change was accepted without updating the build page, but my guess is that since the commit doesn't mention the change of sensor and the amount of code changed is quite large (369 additions and 252 deletions) nobody noticed that a new sensor was used.

I'm trying to address the sensor change in https://forum.mysensors.org/topic/9801/bmp-e-atmospheric-pressure