Marco Lurati

Voce di Blenio

Multimedia installations and digital web archive

Abstract

The temporary exhibition narrates the 50 years of the Blenio valley (Switzerland, Ticino) that have been documented with 50 years of uninterrupted publication of the monthly journal titled "Voce di Blenio".

Starting from the material selected among the 600 editions of the monthly journal, the visitor will discover the most relevant moments and events of the last half a century, highlighting the changes and what stayed the same, making the exhibition a model to narrate the destiny of the alpine regions.

Datas

year

2020

scope

freelance

collaboration

Edy Radice Elia Schneider

client

Museo della Valle di Blenio


skills


process

The digital archive

The digital archive contains all the publications of the 50 years of the monthly journal titled "Voce di Blenio". That means 600 editions, resulting in 8'701 pages.

The goal was to build a web app capable to search any terms among all the pages and show only the one containing those terms in the specific selected time period, as well as scrolling through the list of all the editions organised by time.

Each page was a single PDF file, the oldest one coming from the original scanned pages with an OCR (Optical Character Recognition) program to get the text content digitally, and the newest one simply exported from the editing software used to write them. The overall space taken by the files was about 9GB. So, quite a daunting task!

The PDF web viewer choosed has been PDFjs, free and opensource. The web app running locally has been written in PHP, JS and AJAX.

As you can imagine, directly searching via web in 9GB of PDF files, even if locally, is a very demanding task and takes a lot of time, so a better method had to be found. The solution consisted in automatically scanning all the folders containing the PDF at the start of the local server, and update a single JSON file containing all the text of each individual PDF as well as it's path for later linking.

In this way, the searching task was performed on the lightweight text JSON file, and the HTML page with the results just contained the link to the corresponding PDF file that eventually would be open with PDFjs once the user clicked on it.

The web app resulted very snappy and quick, even on the old PC used during the exhibition (also a display object part of the story telling). It did required a change form the Windows XP OS on the original mechanical HDD, to a much faster SSD disk with a lightweight Debian distro to be able to run the server for the web-app.

The experience continued to a more physical one once the visitor decided to print the selected page with the dedicated button in the web app on a A3 printer connected to the PC, to keep a copy of it for him/her to bring it at home.

Vintage radio

The playback of some old interviews about the journal has been integrated in an old radio also object of interest of the exhibition. This old AM/FM radio has been upgraded in order to play digital audio files from an SD card using the headphones or the added integrated speaker and by still using all the knobs and the original interface.

Everything is based on a Teensy 3.2 board with its original audio shield. The analog and digital pins read the potentiometers and selectors of the interface as well as controlling the tuner LED and its analog dial (PWM pin). To simplify all the wire connections, I designed and build a PCB board and cut it on a small CNC milling machine.

The old mechanical variable capacitor responsible for the frequence selection of the tuner has been removed and retrofit with a potentiometer mounted on a 3D printed reduction gear system in order for the Teensy board to still read the current tuner position.

The simulated tuner works conceptually as any analog radio tuner but it's fundamentally different; the powerful Teensy board plays the audio WAV files once the selected tuner frequency corresponds at the name of a file on the SD card, for example at 98 MHz it will play the file 98.wav (if present obviously). If at the current selected frequency there is no corresponding audio file on the SD card, the Teensy board will play internally generated pink noise to simulate the radio out of tune.

When the tuner get closer to the frequency of an audio file (originally a radio station), the volume of the pink noise diminishes and the one of the audio file increases. Moving passed the audio file frequency, the reproduced sound will fade back to the pink noise.

Internally the Teensy board also changes the sound regulating the volume, bass, trable and right/left balance according to the position of the corresponding knobs on the radio.

So, all in all the radio still works as it did originally, feeling exactly genuine.

Video projection with capacitive interface

One of the rooms has been dedicated to the playback of old videos about the valley. Because of the limited space, using a dedicated table or stand with the interface to select and play the videos was not desirable.

So the control interface has been integrated and projected directly on the screen; three conductive surfaces has been mounted behind the screen at the right height to match with the projected buttons to move up and down in the list of the videos and the play button as well.
The three aluminum plates had been connected to the touch pins of a Teensy board used to communicate (as HID interface) with the Processing sketch responsible of the playback and projection of the videos.

Once a video is selected, the interface disappear leaving the full screen for the video playback. It will appear again once the video end and the main list of videos appears again.

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