http://ardupilot.org/copter/docs/common-baro-external.html
Hello! There was a big problem when connecting an external barometer to the ArduCopter 3.6.5 (Last stable). In the full list of settings there is no such parameter as GND_PROBE_EXT: External barometers to probe
Therefore, I can configure it external barometer. I want to know why this parameter is missing? Indeed, at the very beginning of the article it is written that since version 3.6 there is such an opportunity.
pixhawk 2.4.6
I found this parameter in the 3.7.0 firmware for KAKUTE F7 but I have not found in the firmware for the pixhawk. It looks like the developers have forgotten to implement an external barometer for pixhawk. I am also interested to connect an external barometer. I will wait until it is possible…
It is very sad that the developers made such a mistake, maybe they should say it somehow, don’t know if there are any topics or email for bug reports?
Hey.
The external barometer in the firmware version 3.6.6 will be included extensively. I heard from the developer 
greetings
Wow! I look forward to this! Thanks for answer
I enable and connected external barometer but it is not showing in mission planner plz help
Probably a connection issue - you need to provide much more detail including what baro is it and wiring and where is it connected to on the flight controller? What flight controller?
I am using pixhawk which is showing warning given below so i ordered a ms5611 barometer for using externally with pixhawk but pixhawk is not detecting the barometer.
That link is not for a baro.
Please also describe the connection details, how you wired it - or a picture.
Link for barometer
I have connected according to document provided on arducopter website about connecting external barometer to pixhawk using I2C.
Devices that can do SPI and IIC (or I2C) almost always come configured for SPI.
Was there any information on how to change it to I2C, or change the I2C address?
I will try to interface that board with arduino and update you, there is no jumper provided for selection of spi/i2c. Here is a tutorial i found on instuctables.
If you’ve got an arduino to test with, this sketch will tell you if it can find an I2C device. That will at least get you started.
I2C_Scanner.zip (513 Bytes)
According to most info I can find, your board should just work in I2C mode - you can safely swap SDA and SCL wires to check for wiring faults.
You can connect PS to VCC to ensure it goes into I2C mode, and connect CSB to either GND or VCC to change the address.
I have tried everything, it works on arduino . The arduino can scan the i2c adress it is either 0x76 or 0x77. Nothing happens and the pixhawk doesn’t show any values of ext barometer. Please help.
Please also visit this topic Prearm error GPS alt error 5850m (see BARO_ALTERR - #2 by Rajnikant
This is the real problem.
Got an update , a good news just did everything again, like uploading firmware and etc from start and it got detected.
BARO_ALTERR_MAX It will have 2000. may! according to me
