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Itärastit Latokartano

This was the last itärastit event for this year. See you next year in April again!

#2: wrong direction and slow pace out of #1 is probably the cause of the bad split.

#4: completely lost it when almost inside the control circle. Through to the big road and even ran along the road in the wrong direction for a bit...

#11 down the hill too much to the north, then looked for the control in the wrong place before I found the bend in the road,

#15 tried to look for the path marked with a thick dashed line, but there are many paths and it's not clear which one to follow. Might have been faster to simplify the plan and run to the big road behind #10 first.


Installing the latest KiCAD on Ubuntu 14.04LTS

Add the ppa:js-reynaud/ppa-kicad to your list of sources:

sudo add-apt-repository ppa:js-reynaud/ppa-kicad

Then update package repository info

sudo apt-get update

Then install kicad

sudo apt-get install kicad kicad-common

Done. As of 2014-10-19 I get "Build 2014-jul-16 BZR unknown" - which should be new enough to contain most of the features I want.

There is a problem with this install because the environment variable KIGITHUB is not set. We do that by adding this line to ~/.profile

export KIGITHUB=""

For this to take effect you need to log out and then log in again. You should now see KIGITHUB defined in the under Preferences/Library Tables in Pcbnew. I still have KISYSMOD undefined, but that doesn't seem to matter(?).

So far so good. Next stop is learning how to work with the kicad github plugin so I can store my own symbols/footprints in my own github repo.

Fusion splicing optical fiber


I spent most of the afternoon splicing this thick 12-strand single-mode cable to an LC patch-panel.

The fusion splicer and cleaver we have are quite similar to the ones shown here:

Iltarastit Kivikko


The last Iltarastit event for this year.

A map with lots of details and lots of controls. 24 controls on a 7km course means 280 m/leg on average - at a pace of 10 min/km that means there's a control to punch every 2min 48s during 70 minutes of running. I was slower than that however, roughly 81 min...

Itärastit Kauhala


Had to use a hand-drawn map, since they had run out of printed maps.

Towards #1 I am correctly on course but then run down the hill to some big stones which were not the correct ones. Probably +2 minutes and the second-worst split.

#5 is jointly the best split (with #9), but I would have liked to stay along the edge of the blue swamp and not drift right and high up on the hill.

#10 is the worst split, but a short leg so not that much time lost. Maybe everyone else used the two paths and the flag was clearly visible from the second path?

Overall 10th out of 62 runners which is OK.

Espoorastit Latokaski


Maybe a bit straighter to #1 would have been better? Then a slow S-bend avoiding the wet(?) bit between #1 and #2, which was very slow. Similarly straighter out of #2 towards #3 would have been faster.

Surprisingly #4 is the best split - probably because someone else was in front of me until just before the control...

The route choice down the hill from #4 towards #5 was not fast, and I had to backtrack and look for a place to cross the stream. Rounding the swamp to the north would have been an option too. Then close to the control I climb the slope to slightly the wrong cliff loosing a little time.

#7 through to the finish are all quite straightforward. Just after #7 I almost hold the map 180-degrees the wrong way but quickly correct my mistake. Before #9 I follow someone else onto the yellow field when staying on the path would have been better.

Itärastit, Nuuksio


+3min loop when just inside the control-circle at #3. I blame other runners that distracted me.

+4min loop east of #5, also from within the control-circle, because I thought I had crossed the swamp west of the control and needed to look for it more to the east.

+2min at #7 because after the big swamp it was difficult to know where exactly through the green thick area one approached the control, and I mistook the westerly big stone for the more easterly one directly on the #6-#7 control-line.

Without the mistakes that cost +9min a top-10 placing would have been possible - well maybe next time...

Iltarastit, Solvalla


Nice going on four out of eight legs of the course.

Out of #1 I have the wrong direction and loose 2-3minutes probably.

#5 (3 on the map) is a horrible mess where I drift down the correct hill not really knowing where I am - worst split by far :(

Itärastit, Paloheinä


A great big loop around #2 that cost at least +3 minutes :(

Then I ran past #5, just didn't look in the right direction at the right moment. Maybe +1 minutes here.

Out of #8, should have avoided the green dashed slow area by rounding it clearly north or south - very slow going until I reached the road. Another minute lost there probably.

Overall an easy course with emphasis on running - as long as clear and good route choices could be made...

TEC-Drive v2

Sadly TEC-Drive v1 died an untimely death when it overheated due to being powered from +/-15 V instead of the designed +/-5 V.

TEC-Drive v2 is a simplified design using TO-220 packaged LM317/LM337 adjustable regulators and the OPA569 high-current op-amp.


Constant-current drive is achieved using the OPA569 (U2) I_monitor output. I_monitor sources/sinks a fraction I_out/475 of the actual output current. By using another op-amp (U1) in a transimpedance configuration we get a feedback-voltage proportional to the output current.

PCB layout on a 100 mm x 160 mm eurocard:



Built and assembled as a plug-in card for a 3U rack. Note big heatsinks on the +/-2.5 V regulators.


The DC-response is I_out = 105 mA/V * V_in, with an offset at zero-input of -4 mA.


With no low-pass capacitors (C1 at the input, and C11 over the transimpedance-resistor) added and a purely resistive load the frequency response extends beyond 1 MHz with some ringing.