Flying AdHoc Network

The first time I heard about FANET was at a gathering of some paragliding friends last year. They mentioned that they can display each others position on their flight computers. While that sounds cool, I don’t often get to fly cross country any more. Thus this feature was not of particular interest to me. Then some months ago I read an article about the Skytraxx 3.0 in a paragliding magazine. It was mainly focused on the builtin database of aerial obstacles, namely dangerous cables. But it also mentioned that weather stations could broadcast wind information on FANET, which the flight computer would then display in real time. Now that was more interesting to me. The part I like the most about the FANET technology is that it is an open LoRa mesh network. I watched a video where the developer explained that it is even possible to transmit landing procedures based on wind direction to be displayed on the flight computer. Further pilots can send messages to each other, and change the mode from “flying” to “retrieve car” or “need a ride”. All of this together was too much to ignore.
While FANET was developed by Skytraxx, it is an open protocol, and other companies started including support for it in their devices. The Skytraxx devices that come with FANET, also include FLARM. FLARM started as collision avoidance system for sailplanes. But in the meantime, most light aircraft are equipped. Devices for paragliders only transmit to FLARM. They are unlikely to crash into one another due to the slow speed. But by transmitting their position, faster aircraft can be warned soon enough about their presence. Like FlightRadar for big airplanes there is GliderNet based on FLARM and SkyNet based on FANET. These sites are fed by ground stations that decode the signals broadcast by the aircraft. All you have to do in order to appear on these sites, is register with the Open Glider Network. If you register in addition with LiveTrack24 and link your OGN registration (the FLARM id), then your flights are automatically archived. What I like most about this, is that I can give the URL to my beloved ones. If I’m not home in time, they can check if I am still airborne, and where my last recorded position was. So in the improbable case of an accident, they could send search and rescue in the right direction.

Technical inspection with the Tesla

Cars have to go to the technical inspection every second year in Switzerland. New ones are exempt from this for the first five years. Now that my Model S is closing in on becoming six years old next month, I got the invitation to bring it in for inspection. Usually with my old ICE cars, I would visit the mechanic beforehand to bring everything in order and to wash the engine. The Tesla has no dirty engine to wash, and was in service last July. So I completely skipped the preparation part.
As usual, the expert performed a short test drive with hard braking. Then followed the indoor inspection. Testing brakes, suspension and lights was as usual. But that was it already. He admitted that he didn’t have much training for Teslas. His manual seemed to indicate that the parking brake was mechanical, while I am convinced it is electronically activated. So he tried to spot the cable. But we were unable to figure out which way it was, because everything is so well hidden behind covers. He said that the lower part of the car looked like from formula one, and wanted to know what material the shield of the battery was made of. He did not have a single complaint, and was done in less than 15 minutes. Wow, I never had a car before that was through the inspection so quickly.

So now is a good time to do some recap. I had the car now for three months short of three years. During this time, I did the following to it:
* Added 95’000 km to the odometer (essentially doubled it)
* Charged 19’208 kWh
* Paid CHF 2’082.5 for electricity
* Paid CHF 63.5 for parking that was only necessary for charging
* Bought three sets of new tires, that I paid all with Bitcoin

Here is some statistic about where I charge:

* 65% at home (typ2 16kWh)
* 15% superchargers
* 13% typ2 22kWh. Probably the lions share of this is the public charger near my in-law’s place, but it also includes Tesla destination chargers and most public chargers in general.
* 2% Chademo (50 kW) and CCS (150 kW)

Given that only 2% was Chademo and CCS together it seems silly that I bought both adapters that cost together close to CHF 1’000. But it was mainly about peace of mind, being sure I can charge everywhere. During holiday trips each one of them proved invaluable. Even if I have an insurance that covers the cost for towing, it would be very inconvenient to get stranded, especially far away from home.

I had a couple of repairs:
* Two xenon headlight bulbs replaced
* One 12V battery replaced
* One door handle replaced with newer version (known problem with the cable to the micro switches in the first revision)
* Tire pressure monitor system replaced with newer version.
* Front brake disks and pads replaced. Was damaged from under usage due to recuperation.
* One electric motor replaced under warranty. It worked still fine, but it was not completely silent any more.
* Replaced all lug nuts, because somebody damaged them using a wrong tool when changing tires.

In total, I paid something more than CHF 4’000 for all the repairs.

When a product is better than the description

When I was a kid I liked wrist watches from Casio. I had one with a calculator, one with an address database, one with an infrared remote control and one with an altimeter. But for the last 25 years I didn’t wear one. I don’t like to wrap anything around my wrist. And since I carry a phone, I have a way to find out what time it is.
When friends and neighbors started wearing fitness trackers, I thought I don’t need that. When I went running, I did it for my personal fitness, not to compare to somebody else. And I can care about my fitness without a device telling me to walk some more before going to bed. When my wive wanted to gift me a step counter for my birthday a couple of years ago, my response was: thanks, but no thanks. I have no use for a step counter.
Some times I brought my phone when I went running to record the GPS track just to try. Some co-workers upload all their activity to Strava, and claim “if it’s not on Strava, it didn’t happen”. Not so for me.
Since I started carrying my ultra light paraglider for run and fly, I took the phone with me more often. In the backpack it disturbs less than in the shirt. The main reason for carrying the phone was to be able to call for help in an emergency. And when I brought the phone with me anyway, I could just as well run the tracker app on it. But unfortunately it didn’t work very reliably. When the screen was off, it stopped tracking, and when the screen was on, it often registered fingers that weren’t there. So it happened often that it stopped tracking after a while, or deleted the track entirely. Sometimes I had a ton of apps open after running and I didn’t know what else happened to my phone. But still, with the few tracks that recorded at least the uphill running part, I could see my progress on that segment. That turned out to be more interesting than I anticipated.
So when my wife recently wanted ideas for my birthday, I told her “a cheap wristwatch with GPS tracker, that works without a crappy lock-in smartphone app”. My absolute nightmare is to have a closed source device that tracks my every move, where I have no control over the data it collects. Worst of all, it would become useless when the manufacturer decided to stop maintaining the app. I don’t want devices with planned obsolescence. Of course I had to do the research myself. On the product page they only mentioned their iOS and Android apps, which are of no use to me. I noticed a while ago, that there are some packages in the debian repo for Garmin Forerunner devices. Further research brought me to quite complicated methods to get the data from these watches. But then I found a page that stated that when you plug in the watch with its USB cable to a computer, it mounts a filesystem and you can just copy the activity files. If it is really that easy, then I really don’t understand all the fuss. Everything seemed to indicate that all Forerunner watches come with a USB cable for charging the device that also acts as a data cable. It is beyond me why they don’t mention that explicitly on the product page. So, for my purposes a relatively cheap Forerunner 30 or 35 should be just fine.
And so I got one for my birthday from my wive. It even has a heart rate sensor that I wouldn’t need. And indeed, just plugging it in with the USB cable, I can grab the fit files and either upload it directly to Strava, or convert it to a more common format using gpsbabel.