Contemplations by Thor /tɔː(r)/

Initial testing of our SINTSENSE analytical systems with PID, SO2, NOX, OX, H2S, and CO sensors have indicated some drift when testing them in ambient air. Especially the electrochemical sensors have been prone to inversion, and some of the sensors show opposite polarities. There is enough examples of published data from sensors of this type without calibration and validation of drift, cross-sensitivity etc., so a proper calibration needs to be done. I have access to a very elegant gas and liquid mixing system that should make it possible to evaporate a solution of benzene, and air mixtures of SO2, CO etc. Air because these sensors require oxygen to function. In the mean time I thought it would be a good idea to test the sensors on the exhaust from my beloved BMW vehicles. So I gave it a go. From the figure it can be seen that for both vehicles the PID sensor saturates at about 35 ppm. No worries: I have on for the working range of 50 ppb to 6000 ppm to try next. The CO sensor behaved ...

I finally got a smart watch! After thinking of buying one for years, I finally managed to choose one. It was hardly any compromise, well maybe except for the price ... I can' think of how many times I almost bought an Apple Watch. The battery life usually held me back: charging the unit every other day was not acceptable. I remember waiting for LTE a while, but when it finally arrived the penalty on battery life (and my wallet) was not acceptable. I record all my physical activities on Strava. It's mostly bicycling, running and walking. Using my iPhone X as recorder has worked great, although there have been situations where I wish I had another alternative for recording the activities. The phone battery is sometimes needed for other functions, and for running with the phone in an armband is cumbersome when you need to look at the map for directions. I am not a dediated 4-by-4 interval trainer. I prefer to run in the forest where the elevation profile gives me natural int...

Our cabin is in the mountains near Tynset. Since we always heat it, it made sense to install a smart plug so that we could control the heating from home, and have it warmed up while driving the 2,5 hours to get there from home. I selected a plug I could control over wifi, and not just an app: D-LINK DSP-W215. Since I have a RPi installed, I created a python script to control it over ssh from home. It works nicely for scheduling, a feature yet to be implemented in the app. Sissel and I have designed a lamp to be installed in one corner. It's a simple wall lamp made in massive oak, a concrete covered socket on a gray textured cord. We had planned to use a led decoration bulb like the ones we already have. I was thinking how to implement on/off and dimming of the bulb, when I found that Philips had the solution: a smart bulb with all required functionality. Home made smart lamp I tested the bulb with the Philips app at home, and it communicated nicely over bluetooth with ...

Well, I could not help my self for long: dumping data to influx is simple and Grafana is pretty self-explanatory.  The Worldmap plugin is not made for temperatures, but I managed to create a map that made sense with respect to temperatures, and to get actual reading when hovering over them. As I have collected no more location information than lat/long, I got an n/a when hovering over the locations. Since I have altitude, I could replace the n/a with some useful information.

I have Netatmo weather stations both at home and at our cabin. I retrieve the data from the stations to my own server, and store the data in CSV file as well as in an influx database. I use Grafana to plot the data and to generate monthly and annual reports. The data is retried with bash and python scripts. About a year ago I noticed that Netatmo offers retrieval of data from public servers. For an area defined by latitude and longitude, the data from weather stations in that area could be retrieved.  I managed to retrieve the data, but as my python skills were limited I was struggling with retrieval of specific (e.g temperature) data. Data typically looks like this, with some variety depending on the public data offered by the individual stations: [ { "_id": "70:ee:50:36:dd:2e", "place": { "location": [ 9.877501, 62.842563 ], "timezone": ...

As a scientist, I work with the characterisation of gases. For this purpose, I use professional analysers of various types: fourier transform infrared spectrometers, mass spectrometers, gas chromatographs with a plethora of detectors and tunable diode lasers. These instruments are expensive, typically in the range between 15-150 k€ and the number of instruments available to me is limited. The instruments performance are well established: accuracy and precision, sensitivity and selectivity. Most of the instruments I work with are multicomponent analysers; the ability to deconvolute interference from gas species has been vastly improved over the years by signal resolution and multivariate calibration. While industrial process monitoring normally are discrete measurements, fugitive emissions and environmental monitoring generally improve with spatial resolution. This has been an important driving force for the development of low cost gas sensors. While the analytical performance ofte...