Since a long time I’ve been somewhat frustrated with how difficult it is to use MIDI with Arduino-based devices when connecting them to a computer by USB. If the ‘duino implements the MIDI protocol, basically I want to be able to set it up as a MIDI device to communicate more or less directly with other MIDI based software on my laptop. But because the FTDI USB drivers present the Arduino as a serial device, and there seem to be no utilities available to convert serial to and from MIDI, this has been quite impossible.
Well, no longer so. I’ve written a small command-line utility which connects a MIDI device to a serial port. Furthermore it lets you connect using non-standard serial speeds such as the MIDI standard of 31250 baud.
-p FILE set serial device
-s NUM set serial speed
-v print messages sent/received over serial
-l list MIDI input/output devices
-i NUM set MIDI input device
-o NUM set MIDI output device
-c NAME create MIDI input/output device
-h or --help print this usage information
This is actually extremely useful for MIDI DIY-ing. If you wire up a DIN plug to the Arduino you’ve got an instant MIDI out port (see for example Todbot’s Spooky project), but since MIDI runs on 31250 baud you are out of luck with USB – most applications, including the Arduino IDE and Processing, only accept standard serial speeds, and MIDI applications still don’t do serial.
The utility is written using POSIX termios for serial comms, and the cross-platform JUCE library for MIDI, and should compile on Linux and Windows as well as Mac OS X. I’ll try to make a Linux build available soon. It should work fine with any serial connection, not just Arduinos.
Ah, so while writing this I’ve made the inevitable discovery that someone’s beaten me to it – in fact there seem to be several utilities doing pretty much the same thing listed at arduino.cc. Well there doesn’t seem to be a Mac version around so maybe there’s room for another.
Another discovery I’ve just made is that cvs.pingdynasty.com is, um, not showing up the project, or anything else for that matter. I’d better get on that, then. In the meantime, get the source code from here, and a Mac OS X 10.6 i386 binary here.
Okay so it’s February already, but things are finally moving again with the project and a few new PCB’s are on order.
The previous design that we tried used a MIC5891 serial-input latched source driver. This seemed perfect on paper, but turned out not to work at all with 5v USB power because the IC drops too much voltage to drive the LEDs. Dang! And having at least the option to power by USB only is something we don’t want to sacrifice.
The new design by contrast uses discrete transistors to drive the LEDs, which are multiplexed by the microcontroller. This design can take a separate, higher input voltage, but also works fine with 5v. At least it does on the breadboard, we’ll have to wait and see how the PCB behaves!
Delivery is due in early March, news to follow shortly thereafter.
Due to certain intermittent, but persistent problems with the last batch of PCB’s we’ve decided to make some design changes.
This means that BlipBoxes will not be available for sale for yet a bit more time, so apologies, again, to those of you waiting.
We don’t want to offer up a device that is not completely reliable, but rather take the time to fix the problem properly.
The good news is that we are already testing a new circuit which includes the MIC5891 source driver. This can drive the LED’s with up to 500mA, which is more than enough for our purposes. In fact, it should be more than enough even for a superbright blue LED version in the future.
Prototype PCB’s are currently on order, we expect to have them fully tested within the week. More news to follow.
Sometimes an idea just gets hold of you, with no regard to how crazy it really is. It keeps churning away in the back of your mind until eventually you say alright, let’s just whip out the soldering iron and do it.
Our good friend and talented designer Jim Otton has done a brand new BlipBox logo, which now adorns both our blog and website. He’s also done some other designs for us, more of which you will be seeing soon. We hope you enjoy.
The new aluminium enclosures have arrived, custom milled and ready to be stuffed with electronic goodies.
This means we can now sell a number of ready made BlipBoxes, as soon as we’ve made them that is. Those on the mailing list will be informed of all the details.