bmp085 + Arduino Pro mini as Variometer


i want to build an Variometer with an Arduino Pro mini and a bmp085. I will use it in mein DLG and so it needs to trasmit the Data to a second Arduino on the Ground. Does anyone did this already here? Which RX/TX Module can i use best (433mhz, 2,4 must be legal in germany!)



wrt BMP085 pressure sensor:

No experience with 433 yet ..

Hopes this helps, Rob

am i right this is for a rc plane ?

Yes Gadget, you are right!

I recently built a vario for paragliding, using the ATMEGA328P with arduino bootloader and a BMP085. Works very well, my next project is a TEK vario with two BMP180s for a manned glider. Did you have any success yet with the radio part? What filtering code do you use for the vario?

RaoulDuke, Hello, can you share me , please, how did you make the vario with BMP085? Thank you Gerardo

Isn't a Variometer a Phase Variable Transformer???

Why ask when wikipedia knows...

Well, the Variometer reference is to a 1930's device built for MW receiver antenna tuners as a variable broad band antenna tuner. I am also aware that a Variometer is a Barometer with a different calibration and scale and that rates of ascent and descent are as important as the actual altitude, also that various conditions might need to be met if any of those parameters are beyond established parameters. There is available some 'C' code that would make the technical backbone for an Arduino sketch.

I'm a paraglider pilot and teacher. The vario part is easy with bmp085 will share code for altitude while hiking. The XBee part is easy too. Just need to put them together. What range distance do you need? Why do you want that data on the ground?

I have built some arduino-based variometers for soaring model gliders. The idea is to be able to somehow sense the on-board variometer signals on the ground, in order to center the glider in thermals. With no vario feed-back it can be very difficult to judge vertical speed from a distance, especially when flying directly overhead. You can read about the construction of three tested versions and download the sketches here: .

The first version used the Pro Mini board with the VTI SCP1000 barometer/pressure sensor and a pair of PMR radios. It worked very well as such, but the radio transmission didn't, unfortunately.

For the second version I used an Ardweeny board (which is also pretty minimal in size and weight) and the Bosch BMP085. This time I tried a cheap 433MHz radio which was a dispointment in terms af radio range.

The third and present version works great, I am glad to say! It uses the Pro Mini 3.3V/8MHz and the BMP085 combined with an XBee Pro system. Also I added a SpeakJet synthetic voice chip to the receiver circuit, which spells out the altitude of the model! I have not tested the ultimate line-of-sight radio range yet, but it certainly functions well so far when soaring thermals up to a circa 300 m above ground.