Introduction to the openx vario/altimeter

[Flaps 30]

Thanks Rainer. That has raised many more questions, as would be expected. I will hold back from bringing them up at this stage.

I do have one question that I would like ask - If you are buying the Pro Mini board. Does it matter if it is fitted with the Atmega168 instead of the Atmega328?

[rainer]

If you are buying the Pro Mini board. Does it matter if it is fitted with the Atmega168 instead of the Atmega328?

go for the arduino pro mini with atmega328 5V 16Mhz.
it´s probably working as well with the 168 version, but the price difference is almost nothing and i am only using the 328 version, so its tested.

[rainer]

here´s how it looks like in open9x:

ALT => the relative altitude
VSpd => the vertical speed
Dist => 279.22 the absolute height as calculated form air pressure+temp
Cels => the input voltage of the arduino
RPM => 1056 mbar = the current air pressure (not the best resolution in this field...)
T1 => 25C the temperature measured by the ms5611

the dist and RPM fields are being "misused" a bit here

you can configure this to your liking by just uncommenting some lines in the code.
e.g. you can choose what you want in the dist or RPM field: nothing, Altitude,Air pressure..

[Rob Thomson]

And I thought you where just going a vario?

Sent from my GT-I9300 using Tapatalk 2

[jhsa]

Any chance of changing the names for this device? for example:
Alt to RAlt , Relative Alt
Dist to AAlt, Absolute Alt
RPM to Prs or Bar, Pressure

[rainer]

yes, changing names would be nice, and having a better way of writing to the fields in order to have full control over the displayed value would be even better. ( 0.0 to 6533.5 to dist, and rpm, or 2 other fields).
don´t expect too much from the absolute alitude field though. As this is just a pure calculated value it will vary quite a lot.. in the last days i had altitudes between 145 and 350m being displayed just because of weather changes...

[jhsa]

One day we will do it as in the 1:1 aircraft.. insert the pressure and the altimeter will display the correct altitude..
I think the important altitude is the relative one.. that is what we will use, I would say. will the 9x display also negative altitudes?

João

[rainer]

One day we will do it as in the 1:1 aircraft.. insert the pressure and the altimeter will display the correct altitude..
I think the important altitude is the relative one.. that is what we will use, I would say. will the 9x display also negative altitudes?

João

yes, negative altitudes work fine for the alt field

[jhsa]

I just can't wait to having the sensor in my hands.. I even had to set up a glider for it
Some club friend gave me his old glider.. good timing

[Flaps 30]

the easiest way would be to use an arduino nano instead of the pro mini. it has a mini usb connector builtin and is only slightly bigger.

There might be a problem with that, as the nano supply voltage limits are 6 to 20 Volts. So supplying it from the RX supply isn't going to be such a good idea. --> http://arduino.cc/en/Main/ArduinoBoardNano

[rainer]

the easiest way would be to use an arduino nano instead of the pro mini. it has a mini usb connector builtin and is only slightly bigger.

There might be a problem with that, as the nano supply voltage limits are 6 to 20 Volts. So supplying it from the RX supply isn't going to be such a good idea. --> http://arduino.cc/en/Main/ArduinoBoardNano

if you use a BEC, you can provide 5v to pin 27 and it will work. if you use higher voltages in your plane without a BEC, use pin 30 for 6-20v, if you are below 5v it might still work on pin 27, (4.5v is fine)

[rainer]

OK, i started to add some better build instructions. as i don´t want to maintain it on two pages, i removed the build instructions from the first post and added a link to the wiki:
https://code.google.com/p/openxvario/wiki/Main
the next steps are planned if i receive my sensors..
rainer.

[Flaps 30]

Nice work.. Thank you!

One thing I couldn't find was the .INO sketch file. On the Wiki you had - 'here is the arduino sketch you have to put on the arduino.' and no link was given.

[rainer]

Nice work.. Thank you!

One thing I couldn't find was the .INO sketch file. On the Wiki you had - 'here is the arduino sketch you have to put on the arduino.' and no link was given.

i added the link. you have to load this file with the arduino ide and upload it to the board ( this will automatically compile it as well)

[RightRudder]

[quote="Rob Thomson"]Oh... Of course.

Everyone has their own preferences

Ok my preference would be to have silence at and around my normal smooth air sink rate (and to be able to define this of course). A constant low raspy alarm tone when sink rate exceeds a set limit (sink alarm). A climb rate proportional pitch beeping when in lift. This really gives you all the needed info audibly so no need to glance at the display.

Joe

[rainer]

i created issue 190 in open9x to request a change to the range of the inner audio limit: http://code.google.com/p/open9x/issues/detail?id=190

[rainer]

Ok my preference would be to have silence at and around my normal smooth air sink rate (and to be able to define this of course). A constant low raspy alarm tone when sink rate exceeds a set limit (sink alarm). A climb rate proportional pitch beeping when in lift. This really gives you all the needed info audibly so no need to glance at the display.

That should be (almost) possible with the next release.
Betrand added the 4 config values for the vario tone range on the telemetry setup screen.

<lower range limit> <sink tone start> <rise tone start> <upper tone limit>

== The lower and upper limit will be used to define the range for the tone generation ==
The range is -10..-3 for the lower and +3..+10 for the upper limit in 1m/s steps . Theses 2 values define the possible range of vertical speeds that will be mapped to different audio results. if you want to have a sensitive audible feedback, you might want to set these to outer limit e.g. to -3 and +3. this will result in all the possible audio pitch and beep speeds to be used for vertical speeds of -3 tp +3 m/s

== The inner limits ==
The range her is -2..0 and 0..+2m/s in 0.1m/s steps
The inner values will be used to define a silent area for the vario tone. you can set these for example to -1 to +0.20 . This will tell the vario to be quiet in all vertical speeds between sinking -1m/s to lift of 0.20m/s .
rainer.

[jhsa]

Rainer, My sensor it still not here but how could I tell which one I have? 5V or 3V.. The pictures all look equal apart from one that the sensor had a metal case.. I didn't get that one..

Thanks

João

[rainer]

which one did you buy?

[jhsa]

which one did you buy?

This one.

http://www.ebay.de/itm/400343424531?ssP ... 1439.l2649

João

[rainer]

which one did you buy?

This one.
http://www.ebay.de/itm/400343424531?ssP ... 1439.l2649

"Power supply :3-5v (internal low dropout regulator)."
it´s dual voltage. have a look on the item picture: there are 2 voltage inputs 3.3 and VDC IN (for 5V)

[Rob Thomson]

I ordered this type:

http://www.ebay.com/itm/1pc-New-MS5611- ... OU:GB:3160

Rob

[jhsa]

which one did you buy?

This one.
http://www.ebay.de/itm/400343424531?ssP ... 1439.l2649

"Power supply :3-5v (internal low dropout regulator)."
it´s dual voltage. have a look on the item picture: there are 2 voltage inputs 3.3 and VDC IN (for 5V)

Ok, but what about the logic levels.. the arduino pro mini I have puts out 5V I think.. can the sensor cope with that or must I use a level converter.. Sorry, I'm a beginner with these things..

João

[rainer]

in the 2 setups i am working with,both arduino´s operate on 5V and i did not have to implement any kind of I2C logic level compensation. one of the 2 MS5611 operates on 5V and the other one operates on 3.3v. So far no problems, they both work like a charm.

[jhsa]

the sensor board I bought has a 3.3V regulator, right? so that means the sensor is working at 3.3V, even if the supply is 5V.
My arduino Pro Mini is the 5V one.. that is why I'm worried and ask if it will be ok to connect them..

João

[rainer]

the sensor board I bought has a 3.3V regulator, right? so that means the sensor is working at 3.3V, even if the supply is 5V.
My arduino Pro Mini is the 5V one.. that is why I'm worried and ask if it will be ok to connect them..

João

thats at least what i´m doing as well without any problems. i am using a 5V pro mini and connect a MS5611 that has a 5V supply voltage and a lowdrop voltage regulator on it converting the 5v to 3.3v. the MS5611 chip on the module will allways be 3.3V.

[jhsa]

Ok, thanks Rainer

João

[MikeB]

The I2C interface uses open collector/drain drivers that only drive low. The signals have pullup resistors. If they pull up to 3.3V, then the MS5611 is safe, and the 3.3V is just enough to guarantee a logic 1 level into the Atmel.

Mike.

[rainer]

Good news...
i received 2 more MS5611 modules yesterday, so i had a chance to work on the build instructions again:
https://code.google.com/p/openxvario/wiki/Main

The MS5611 module i used is a new type, i did not use before. Interestingly this module is dual voltage and has dual I2C bus output, one for each voltage (3.3 and 5V).
it works as expected.
Rainer.

[rainer]

a new openxvario came to life