data_opera prototyping a dust_data based analogue soundmachine #3
posted by lupo on 15 December 2013

Day No 11/12 30.11/01/12 2013 First reflections: In Helsinki I will set up the sensors with Arduino only to log some data with the same filters which are still in the sensor housings to get data for comparison with the data recorded at Kilpisjärvi. Back in Linz there I have to dig the field of more accurate lowpass filters to get rid of the ripples on the  PWM DC Voltages from the boards and look for circuits for some compression of the signals as low concentration and ratio of particles lead to low voltages while high concentration and ration tend to go over the maximum and are therefor limited with maximum voltage. Driving the darlington transistors with 9V should help as the CV inputs of filters and LFO's can be fed with 9V too. But still I have as well to look for a way to get rid of the linear relation between data and Voltage output, what would perfectly work with logarithmic function to process the data before sending it as depending Voltage. Setup in installation be changed, I will build single stations containing sensor, microcontroler, darlington and other needed analog electronic circuits needed. The locations of single units setup will be choose as it seems to offer changes that emerge from visitors moving causing dust moving which changes the sound. The stations will be conected with one collecting analogue synthesizer rack, where the data related voltages will control pitch, PW of the squarewave oszillators, frequency and resonance or Q of the filters and further CV controlable LFO's. Further I want to do some analogue math with the signals using comparators, analogue logic modules offereing AND / OR / XOR outputs to trigger for example Envelope Generators to fade the Volume of voices or other parameters. Main idea is now to create an sound envrionment that relates to the dust moves in the envirnment where the installation is located. Environment is not seen as the rooms where the sensors are located only, but as well the entrance, a backyard, maybe the nearest street. The entrance situation is most likely intersting, it makes the rooms and the outside environment communicate via airflow and turbulences which triggers changes in the acoustic environment. I think further it needs to make a dislpay or whatever appropriate way of information about which sensors detect dust of which size of particles, of the relation between chosen particle sizes to observe in comparison to particles sizes and related maximum permissible values, and of course on relations of sound changes, sound design and musical interpretation of detected concentrations and maximum values allowed in air. Day No 13 02/12/2013 Some more data logging, some tuning with the code before the dissasembling and the packing started, which then finally lasted for some hours till everything was apcked secure and transportable and sorted to make it easy to reach for the parts needed for data logging to be donne during the crypto-postcard workshop @ Made in Kallion in Helsinki. Day N0 14 03/12/2013 the journey to Helsinki starts. Day No 16 05/12/2013 Did hours of data logging at "Made in Kallio" during the workshop of Markus Decker and Peter Wagenhuber on Cryptology and encryption of postcard messages with personally shared key's. Attending the workshop was very interesting and fun at the same time, and it was quite intersting how much attention the sensor box and the data logging setup gained which led to following talks about my project. Both the results of the logging which clearly showed, that the almost predominant zero concentraions measurings from Kilpisjärvi still derive from the sensors sensitivity, which could be higher, but nevertheless the predomination of non zero measurings in Helsinky to be seen after time even dominated by rain and light snowing, both cleaning the air, shows, that the sensors defintely will be sensitive enough for any area with some density of population to carry out possibilites for the sonification of  environmentally interrelatingly caused change of dust concentrations. During the data logging I did some basic statistics with the data calculating (offline) Average, Median and Mode of both, concentration and ratio of measured values. To use "second order" data could be interesting to drive second order modulators by voltages generated along the (second order) statistical data. But this would involve more math capacities for the microcontroler, so terrain that needs further search for solutions.