VarioVoice

A flight instrument for paragliding and hang gliding that you listen to instead of looking at.

It speaks: height, wind, the drift out of a thermal, and it sounds a variometer. There is nothing to read in the air, which is the point. The phone stays in a pocket.

It is being built and flown. There is no release yet.

Live tracking

VarioVoice can report its position to the Open Glider Network, so that whoever is coming to collect you, or looking for you, can see where you are. It is off until the pilot turns it on, and what the map shows about them is theirs to choose.

A paraglider cannot do much to deconflict, but it helps everyone else to know where to look, and the traffic that matters is faster and is reading a display. Positions are sent from the phone over the internet. No radio is involved, so this is not a collision avoidance system and nobody flying with FLARM will see you.

VVO1A2B3C>OGNVVO:/194125h4543.28N/00924.99Eg135/000/A=001083 id1E1A2B3C +118fpm +5.0rot

Signal strength, frequency offset and error count are left out rather than filled with zeros: a phone on the internet receives nothing, and a field that claims otherwise is a field that misleads whoever reads it. The vertical speed, on the other hand, is measured rather than differenced, which is what the rest of the instrument is built around.

A position goes out when the glider has moved more than 150 metres from the last one sent, with a heartbeat every 45 seconds and never more often than one every ten seconds. Asking for a distance rather than a time is what keeps the gap between two points on the map bounded whether you are circling or on a fast glide, and the distance is set at half of the largest gap worth leaving, so that one transmission lost to a hole in the coverage still lands inside it.

The full message format is documented in the OGN protocol repository.