Table of Contents
Variod
The Variod is a Linux program with the following functions:
- Communication to XCSoar
- User Interface for Volume Control and Tone Settings
- Audio-Vario and Speed to Fly
The Variod obtains data from XCSoar and from the sensord. Have a look at the General operation principle to understand the details.
Internal Data Flow
Sensors –> [i2c bus] –> sensord –> [NMEA over TCP port 4353] –> variod –> [NMEA over TCP port 4352] ←→ XCSoar
Command Line Options
Usually the Variod runs in the background as a daemon, but for special purposes it is possible to start variod with options. Here is a short overview about the possibilities:
variod -v print version information variod -f don't daemonize, stay in foreground variod -c [filename] use config file [filename] variod -d[n] set debug level. n can be [1..2]. default=1
The sound characteristics of the Audio-Vario is defined in the default config-file:
/opt/conf/variod.conf
The following parameters can be set according to your personal preferences:
Audio Vario Configuration
| Name | Description | Unit | Example |
|---|---|---|---|
| Deadband Low | The lower limit for the deadband of the audio vario. | m/s | -0.2 |
| Deadband High | The upper limit for the deadband of the audio vario. | m/s | +0.5 |
| Pulse Length | The length of the pulse generated by the vario synthesizer | samples | 12500 |
| Pulse Length Gain | The gain the pulse length will be boosted if vario value increases | 1.1 | |
| Base Frequency Positive | Frequency of the vario tone if vario value is positive | Hz | 402 |
| Base Frequency Negative | Frequency of the vario tone if vario value is negative | Hz | 350 |
Speed to Fly Configuration
In preparation
Global Volume Control
Global settings of audio-parameters can be made using the alsamixer from the shell, a graphical program which is part of the OV-Linux-Kernel. We recommend to set the master gain to 100%. The settings can be saved with the command alsactl store.
NMEA Syntax
The Variod receives Commands from XCSoar using the following NMEA-strings:
| NMEA-String | Description | Unit | Example |
|---|---|---|---|
| POV | Initial String for OpenVario | ||
| C | Command Mode (XCSoar sends Pilot's Commands to Variod) | ||
| MC | Mac Cready Value from XCSoar | m/s | 1.2 |
| WL | Wing Load | Factor | 1.0 is with no ballast |
| BU | Bugs (on the aerofoil) | % | 10 |
| POL | Polar Coefficients a,b,c | in preparation | |
| VU | Volume Up | in 10 steps | |
| VD | Volume Down | in 10 steps | |
| VM | Volume Mute | Toggle ON/OFF | |
| VAR | Set Vario Mode | VAR | |
| STF | Set Speed To Fly Mode | STF |
The NMEA-strings above are for the Variod only, the complete information about all NMEA-strings used by Openvario can be found here:
Volume Control during Flight
The corresponding User Interface in XCSoar can be found in Quick Menu → Vario
XCSoar Vario User Interface
The Audio Vario has to be activated in XCSoar.
Warning: The sound configuration from XCSoar can be found at Config → Gauges → AudioVario, but it has no effect at all! At the moment the sound configuration has to be done by editing the file variod.conf manually, as described above.
Source Code Details
If you want to know what's inside the variod, you can use a git client to obtain the source code on your local computer.
git clone http://git-ro.openvario.org/varioapp.git
Navigate to sensord
Go back to Overview
Go to Audio Vario / Speed to Fly
Go to Setup Guide