Some silence has been added to the desktop machine:
I had a GeForce 9800gt graphics card previously with good performance but bad power-consumption and noise. The new Nvidia GT640 card should be similar-ish in performance but much less power-hungry and completely silent.
Canon 500D with Sigma 105/2.8DG
Here's the distribution of total time for teams in the Jämsä-Jukola relay:
Here are the distributions of individual times for the seven legs of the relay.
The histogram from the first leg shows bunching of runners into groups - this is different from all the remaining legs.
The 2nd and 3rd leg look quite similar. Note how the histograms lean to the left - there are many amateurs of varying ability which contribute to the long tail to the right.
The 4th and 5th legs are shorter and faster.
The 6th leg is again longer with the final 7th leg being the longest of them all.
Scraping scripts (requires minor modifications to downloaded results html file): jukola_scrape
I ran the second stage (13 km) of the Jukola relay in Jämsä on Sunday.
Clear skies and a more northerly location meant there was much more light during the whole night. Not nearly as pitch-black as I remember in Vantaa last year.
Since there are about 1600 teams competing there will be tracks from 2000 or more runners in the forest when starting the 2nd-stage from about mid-way or worse down the field. This means it's really more trail-running than independent orienteering 🙂 There are tracks to and from each control - you just have to pick the right track among many.
Here is version two of a precision pt100 frontend for temperature measurements between +22C and +42C. The circuit uses a 4-wire connection with a +/-500uA sensing-current. It outputs a +/-10V voltage centered around +32C by way of a 112 Ohm reference resistor. The voltage over the reference-resistor can be used to correct for drift in the sensing-current.
Compared to v1 I changed the current source to the "Improved Howland" design, and assembled the instrumentation amplifiers from zero-drift op-amps with very small input offset voltage and input bias current.
Note: The op-amp shown, AD8551/8552/8554, is a single-supply +5V op-amp and this circuit will not work as such (NI Multisim will happily simulate it though!). Use e.g. OP2177 or OPA2188 for bipolar operation at +/-12 V.
An interesting course with controls #1-#9 in a very detailed area, then a few longer legs to #12 where the course criss-crossed over the swamp a few times before heading back south to the finish.
No major mistakes just minor ones: after #3 did not clearly identify the path, and took a wrong direction down the hill to find #4. Then on the #10-#11 leg I did not want to cross the deep "trenches" on these cliffs, so I back-tracked to avoid the trench (dark brown line on the map).
Here's a sketch for a pt100/RTD frontend circuit.
There are a couple of ideas here which should improve precision:
NI Multisim file for this: pt100_sensor_circuit_v3
Big mistake on #10. Should have run straight south, and navigated after the path based on this assumption. Then didn't do a very good job of promptly correcting the mistake and getting back "on the map" again.
The night of Jämsä-Jukola awaits next Saturday/Sunday.
A loop to Espoo and back. 47 km in about 2 hours.
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