Freesteel Blog » 2016 » September

Saturday, September 24th, 2016 at 1:51 pm - - Flightlogger

I’ve been flying around with my data logger for two years now and I have only this week developed a theory of how to process the temperature data. I might have got to it sooner had I known enough physics or bothered to test the actual response time of my Dallas temperature sensor, which was so abysmal I had to start doing something about it. To be fair, it did take me over a year to even shelter it from the sunlight.

Part 1: The responsiveness of the temperature sensor is 0.09

The apparatus involved running a vacuum cleaner against the sensor housing to create a fast airflow while drawing the air either from the room or down a tube containing a bag of ice.

vacuumapparatus

This was the graph it made, holding the intake near the ice and away from the ice for about 40seconds at a time
temptubeiceupdown1

The curves you see are exponential decay curves, as the temperature sensor cools to the air cold temperature, then warms to the room air temperature, quickly at first, and then slowly as it converges.

(more…)

Tuesday, September 13th, 2016 at 8:25 am - - Uncategorized

Sensible Code

It’s at the Sensible Code Company whose webpage URL is actually sensiblecode.io, even though it’s not in the Indian Ocean.

Company was formerly called Scraperwiki of scraperwiki.com

Nobody ever called my coding Sensible. Things have obviously got to change.

Sunday, September 4th, 2016 at 8:52 pm - - Canyon, Hang-glide

A bit of a bonus holiday slotted in here, with not much time or care to waste on the internet.

With three of us in the car, first we went down to a campsite near Perpignan and picked a 3.6/4 grade canyon of Llech, which was an absolute hit with all of us. There were jumps and toboggans galore, including one called the pistol that shot you up in the air 5m over a deep pool. We need to go back to that area and do the others.

llech2

Then I snuck in three days of hang-gliding off Ager with the bonus help of a retrieve driver. On day2 I tried to go behind the ridge, and it didn’t go well. I don’t know how I pulled it down into the field not of my choice without busting something more than the skin of my knee, but I got away with it.

It should have scared me more than it did. Instead my worst moments of terror were on the K5 rated via ferrata Cast Urquiza Olmo to the west of Ager by the lake.

On the third day up the hill I got an amazingly detailed briefing from some visiting British hang-glider named Al about where to go and what to expect (a huge zone of downwash behind the ridge which you can confidently get through if you start with 7000feet of altitude). It worked wonderfully on my third attempt.

tremp

Then I let myself down by nearly parking my glider on a rebar fence by curving round too wide and falling short of the field I was aiming for.
tremp2
But before that happened, the feeling came over me again where my wings became part of me for those few hours up in the sky. The joy was existential. A lot of the time I was circling with vultures. There are a lot of them about.

In the evening we picked up Becka from Lleida and then went to Torla-Ordesa to see the scenery. Unfortunately the morning buses were all full, and you’re not allowed to cycle up the tarmac road which carries the diesel buses because it’s a Spanish national park, so everything is banned even if it doesn’t make any sense. So we walked in until my foot-soles wore out on the way back and I had to catch the bus.

ordessa

Then, on the way back to France, we dropped in on the 3.2/4 rated Neste de Saux canyon, which wasn’t that great, but we were pleased because we proved we were still up to it.

Now we’re in a gite in Aspet with a bunch of cavers. Everyone is going out to run around the maze known as Felix Trombe, while I have carried on working on the ground window software, where I have implemented a real hack to create flat shading within a the GLSL GPU shading framework:

The trick is to note that the passage tube structures are made from quads which you can colour with 8 colours {-1,1,-2,2,-3,3,-4,4} such that no quad shares a colour with any of its neighbours (edge or corner otherwise). Choose the brightness factor on each quad (say it’s 0which goes:

float flatfac = max(0.0, max(max(abs(vflat4.x), abs(vflat4.y)), 
                         max(abs(vflat4.z), abs(vflat4.w))) - 510.0); 
gl_FragColor = mix(gl_FragColor, vec4(0.0, 0.0, 0.0, 1.0), flatfac); 

groundview3

(I’m now fed up with fighting with this crappy internet connection. It’s probably why I’m getting so much work done.)