Raspberry Pi – Page 3

07/06/2017

20170607

Maisie Williams in 2016.

[…] we should stop calling feminists ‘feminists’ and just start calling people who aren’t feminist ‘sexist’ – and then everyone else is just a human. You are either a normal person or a sexist

Notes to self: Hammeradio operates with scheduled scripts. Access schedules with crontab -e, look for scripts in /home/pi/Desktop/. The entry @reboot /home/pi/Desktop/startupfm.sh launches sudo arecord -fS16_LE -r 22050 -Dplughw:1,0 -c 1 - | sudo /home/pi/PiFmRds/src/pi_fm_rds -audio - -rt Hammeradio & on startup. PiFmRds begins broadcasting at 107.9 MHz. The contab entry 0 */4 * * * /home/pi/Desktop/akustamatashutdown.sh waits for four hours before it runs the script (sudo shutdown). With top you can see active processes. PiFmRds shows ~24.5% CPU and arecord ~4.6%. vcgencmd measure_temp shows a steady 49.4°C temperature.

22/05/2017

20170522

Making the “Hammeradio” launch FM broadcast by scheduling tasks with cron. @reboot /home/pi/Desktop/startupfm.sh works well. It launches sudo arecord -fS16_LE -r 22050 -Dplughw:1,0 -c 1 - | sudo /home/pi/PiFmRds/src/pi_fm_rds -audio - -rt Hammeradio & I’ll also schedule a daily power off cycle for the device. I’ll set it to work during gallery open hours 14:00 to 18:00 (with a Lunch break in the middle). Found an old amplifier circuit I build (while learning to solder to make the WSG) and I’ll test it with the piezo mic I have handy (It would save the iRig pre-amp I bought).

19/05/201729/03/2018

20170519

I got PiFmRds to work on my RasPi3.

Note to self:

1. Use Etcher to flash Raspbian.
2. Enable ssh in RasPi using Terminal
cd Volumes cd boot touch ssh
3. Boot RasPi3, login via ssh
4. Set new password
passwd
5. Set locale
raspi-config
6. Install sndfile library
sudo apt-get install libsndfile1-dev
7. Install PiFmRds
git clone https://github.com/ChristopheJacquet/PiFmRds.git cd PiFmRds/src make clean make
8. Broadcast from usb audio in at 107.9FM in mono 22050
sudo arecord -fS16_LE -r 22050 -Dplughw:1,0 -c 1 - | sudo ./pi_fm_rds -audio - -rt Hammeradio
9. End broadcast
sudo pkill pi_fm_rds

Fiddled with PiFmRds settings (I want it to display Hammeradio as radiotext (RT) but I’m not sure if it’s working). I also want to run a .sh script on boot to launch pi_fm_rds broadcast (aka. step 8). Currently launching the pi_fm_rds from /etc/rc.local. Tomorrow I’ll try to build a cron startup schedule so that I can spare the Hammeradio preamp from excess stress by powering the system down on gallery off hours (I have to use a preamp to connect a piezo mic to the RasPi). Other useful resources for future tightvnc manual.

Installed Sea Change: In the Scale of a Horse (2017) by Otto Karvonen feat Trans-Horse installation at Vuotalo. The installation consists of a performance documentation, a custom horse blanket with an embroidery with the text “Helsingin kaupunki – Kaupunkimittausyksikkö” and horse-gear used by Toivottu Poika during our HKI-TKU-HKI riding trip in 2014.

18/05/201714/08/2019

20170518

Apparently pifm which I tested last year only works in RasPi2 and I’m now trying to get RpiTx to stream FM trough USB audio in (I bet that for what I need it would be easier to buy a RasPi2). RpiTx is very advanced but I can only get it to broadcast audio files over fm (here is a simple tutorial). Unfortunately I can’t get it to stream live audio trough my USB audio interface. Following rpitx-app-note‘s I learned about:

But it is dependent on libcsdr, which I can’t get to compile on RasPi3 because “If you compile on ARM, please edit the Makefile and tailor PARAMS_NEON for your CPU.” and I have no idea on the RasPi3 PARAMS. I found some hints on what to do (but it seems that those are set for RasPi2). Trying to sort the things out by installing gnuradio and other tools as recommended in a different tutorial.

I’ll make yet another clean install of Raspbian and continue in the evening with PiFmRds. I’m using Etcher to write the os on the sd card, which seems to work well. I should learn how to clone the sd card.

Visited Lovi ambient event at Lava klubi and saw a good gig by Rasmus Hedlund and Paula Lehtonen. Their collaboration yelds great results. Paula designed video using material from their trip to Tasmania and Rasmus crafted a field of sounds consisting of oceanic & low jungle rumble tones. Spotted a Make Noise Photogene in use. The gig was constructed out of some 8-10 distinct soundscapes, which were supported by videos from different locations.

09/05/2016

20160509

We met with the “In the Flow” reading circle last evening. Quotes to remember: “…Russian avant-garde art was not directed against the status quo, against the dominating political and economic power structures. The Russian avant-garde of the Soviet period was not critical but affirmative…” Groys on postrevolutionary art in Russia and “Only dull and impotent artists screen their work with sincerity. In art there is a need for truth, not sincerity.” by Kazimir Malevich.

I’ve wasted another day working on the Weird Sound Generator. Replaced every capacitor, added ribbon pins to the wires and resoldered them on board. Double checked the resistor values and pulled out some resistors for testing. Eventually replaced the CD40106 chip.. This returned the voice B Osc.2 but voice A Osc.2 is still missing. I had two chips to begin with and I might have damaged both. During the resoldering session I noticed that a capacitor had been missing a connection from the beginning (because the double sided circuit board I’ve etched is missing connections between sides) and I might have short circuited both chips at some point. I’ll acquire a new chip at some point but I’ll start working on the case now. Working on the board is addictive.

Contacted the Theatre Academy of Helsinki concerning our “Horse and Performance” course which is planned for next fall. They seem excited about our course and apparently students are eager to join register.

Idea: Attach a piezo mic (with a preamp) to hammer and broadcast the audio through the Raspberry Pi radio transmitter (on FM 99.0).