Koodihommia

 I built a simple MIDI looper with the Teensy 3.2 development board  It's a simple device. It has two MIDI inputs, one serving as a THRU port, mostly for forwarding sync messages to the connected device. The other input port is for connecting the instrument. The output port binds the loop for sending and receiving notes. The first version soldered to a stripboard. The left and center MIDI connectors are the inputs connected to the Teensy (header pins visible) through  an optocoupler circuit Teensy is the perfect fit for this kind of project, mostly due to its tiny dimensions. It works with the same development setup as Arduino, and virtually all libraries that work with Arduino work with Teensy. It even includes a MIDI library, which came in handy. The code is trivial; the gist is that we read the input tempo, start and stop messages from the THRU port and merge the tempo message with incoming note data. The note data quantizes to the nearest 8th sync message. Up to date...

I describe how I build the Zynthian Raspberry Pi OS synthesizer from a kit in a previous blog post . It sits mostly idle connected to my sound card, so I decided to make it a bit more useful while it is idling. The first goal was to make it play Radio Helsinki, one of my most played online radio stations. That's simple enough; I just created a systemd service which connects to the stream using mplayer. Note that I'm using jackaudio as an audio "sink." The synthesizer is thus perfectly playable, even if I am listening to something else meanwhile. I get soon bored listening to only one channel. The next step is then to add Spotify. There is a pre-made debian package called raspotify , but alas, the bundled librespot Spotify client does not work with the jackaudio backend. I decided that the most comfortable choice is to compile librespot in the Raspberry Pi and then create a systemd service (after all, that is pretty much all raspotify does). The Spotify client service...

 I have to confess, I'm a lousy solderer, my hands tremble, and I'm often too anxious to get the job done and leave bad joints. To make the job easier, I used on my latest project some external flux (sigh... I know, should have used it always).  A 1 to 4 MIDI splitter. Soldering pen on the left I decided to try out a flux pen. It seemed to be less messy than rosin. I was unsure would it be as effective, though. Well, it was pretty good. It is easy to apply, and I could smear it on the PCB rather accurately. After administering the stuff, I learned that one must be relatively quick to do the actual soldering; it seems to vaporize quickly and lose some effectiveness.

I got inspired by a Youtube video on making a cool MIDI controller by Switch & Lever  https://www.youtube.com/watch?v=JZ5yPdoPooU He uses scrapped/recycled parts for the controls screwed into a beautifully crafted casing. Sadly, I'm not as talented as a craftsman as the Youtuber and could not conjure up the energy to start looting up phone dials and joysticks, yet I took on the project by building up my version. I decided to make a Bluetooth MIDInator.   The Arduino board I use is a Bluno board with integrated Bluetooth  https://www.dfrobot.com/product-1175.html The controller layout is a much simpler version than the original MIDInator with 16 potentiometers and four encoders. First, I forked the repo and took a look at the code. It was understandable and readable, thus a good starting point for the project. I use a breadboard and a potentiometer to try out the MIDI communication through the serial port to a DAW with Hairless MIDI and loopMIDI, ...

After some facade renovations, some of the air vents in some residents in the condominium I live in have complained about bad air quality. I have not noticed any changes but thought that it would be good to check if the air quality in my apartment is acceptable. The commercial CO2 monitors are rather expensive, so I decided to build my own with the Arduino I already own and with an inexpensive analog gas sensor MQ-135. With a few lines of code, the monitoring was set-up by getting an average reading of the air quality sensor in one-minute intervals. The Arduino sends the measurements via serial port to my computer, which then creates a CSV file of the result with a python script. https://github.com/jjylik/arduino-airquality

I stumbled upon the Zynthian  open source synthesizer platform project some months ago and found myself visiting the site even more often than hacker news. Eventually, I ended up buying a Zynthian build kit and did not suffer buyer's remorse since I was looking for a new hobby project anyways which would not be at least entirely coding. Zynthian is in a nutshell, an open source synthesizer platform. It comes bundled with a set of open source Linux synths, effects, and other audio software. The kit I ordered contains a Raspberry Pi, an RPI sound-card, touchscreen, some audio ports, and encoders. All this is connected via a purpose-built printed circuit board. I was a bit rusty on my soldering skills so while waiting for the parts to arrive, I practiced a bit on some old hardware salvaged from my parent's farm. I just merely desoldered and soldered components as a way to practice The actual building was relatively easy, mostly because of the fantastic instructions provided ...

I have the bad habit of watching or listening something from my computer before I go to sleep while already lying in bed. Often when I am on the verge of falling asleep, it is frustrating to get up and turn off the computer. Usually, I put on a timed shutdown so that when I fall asleep, the computer won't wake me up in the middle of the night. However, I wanted to have some other way which does not involve getting up from bed nor having to light up any screen (like my phone) which would interfere with the process I thought about the problem from time to time and it was earlier this year when I bumped into an Instructables  post in which  somebody had made a remote controller for his PC with Arduino as a "keyboard". I thought I would do something similar to solve the shutting down problem because as it happened, I had a spare Arduino lying around After playing around with it for a while, I found out that in my Arduino Uno was lacking HID support so it was not going to ...