(joking)

Great post, Chad. Thanks for taking the time to share.

The trip to Russia appears to be forming in the spring, if you are down for Moscow that is good news as I have been timid about that trip because I will have nobody to go with me.

Last January, I totally predicted this would happen! All the walking/biking, non-genetically-modified food, and cold weather exposure during the Winter creates a virtuous cycle of improving health.

See you soon.
Mom

In other news, I took a new position at work that will take me over to either London or Budapest once a quarter and to Russia once a year. I definitely would like to take a small flight to link up in Berlin after one of these trips. I will be pinging you soon…

Fuck that shit–I’m gonna figure this out for myself, plus this device is supposed to do more than just give me swinging basslines. There’s the iPad-OSC-control thing, plus the hardware knobs that talk SysEx to the Machinedrum. Plus the quantizer, plus, plus…

I hear what you’re saying about the oscilloscope, but I was hoping to go as “circuitless” as I can here. That’s what’s been so cool about the Arduino–I’ve hardly had to do any serious electronic work. Everything just works together. I had to build the MIDI interface, but that was easy and done from a schematic. The Sync is connected directly to pins. And if I interconnect boards, I’ll probably use a digital pin to trigger an interrupt while using the I2C bus to communicate the messages that are less time-critical. Dunno. I still want to try to figure this out on a single chip–no cheating with a second Arduino.

For now, though, I’m getting pissed off at Xcode. It looks like Michael Ashton was right about that one. I may have to got back to the Arduino IDE which sucks. The bit of coding that I did in Xcode was so much easier and readable! The auto-complete was sooooo nice. But for whatever reason, I can’t get make to include my include files. I’ve got them declared and I’ve put them in a directory where they should be found. I’ve tried editing parameters in the make file, but the compiler still gives me errors about undefined shit when it’s CLEARLY defined (double-clicking on a name will take me right to its definition in the appropriate file, for Chrissakes!). The Arduino IDE had no problem with includes. But no auto-complete or any of that double-click-to-definitions-sort of tricks. But I can just stall forever on this.

Do you know anything about compiling from the command line with gcc? Know how to add includes?

http://www.frequencyresponse.ch/?p=shufflebox

You can buy it as a kit, but they also have the schematic. Although the main “brain” of it is another microprocessor like the Arduino uses, and I’m not sure if you can get their code w/o buying it. Then again, as cheap as it is, it might be easier to buy the kit and then splice it into your larger project.

With some of the DIY hi-fi audio stuff I’ve been getting into, I’ve found it easier to copy or adapt an existing circuit instead of starting from scratch. Also, unless you have an oscilloscope, dealing with signals and troubleshooting circuits becomes a big pain. But, there are some reasonable (~$200) entry-level digital oscilloscopes on E-Bay that would work, and there are a few software based scopes that have a USB device to read your signals (~$100). Something that can handle two concurrent signals would be great to actually “see” your delay that you’re putting in. I know it is a fair amount to spend on a tool, but if you’re getting into this and will be working with a lot of signals it can be indispensable.

So, yes, I could make a very simple program on the Uno that constantly polls the serial buffer for any new bytes. If it sees the MIDI Clock byte, it toggles the state of a pin. On the Mega2560, I can use an interrupt that gets triggered if the input merely changes state—from high-to-low or from low-to-high—and use that interrupt to log the arrival time of the MIDI Clock. I’d still like to see if I can come up with a more elegant solution on one processor, but I guess I shouldn’t spend too much time on it if I already have what I need for an alternate solution.

I would need to still monitor Start/Stop/Continue so that I can calculate the current position in terms of beats. My goal is not to merely repeat the MIDI Clock pulses out to the DIN Sync port—I actually want to alter the tempo of clock pulses being sent out the Sync port every 16th note. The goal is to induce a swing feeling in the TB-303 and TR-808 since those machines had no capacity for swinging on their own. Well, the 808 could be made to sort-of-swing by using triplet timing, but swing is usually somewhere between straight and triplet time (or past triplet timing in some cases).

Michael Ashton and I figured out the simple formula for creating two tempos using a sliding ratio. If we determine the incoming MIDI tempo, we can slow down the Sync tempo for a 16th note (causing the even-numbered 16th to be delayed) then speed it up for the second 16th note—this causes the third 16th note to “catch back up” to the MIDI Clock. We then just feed a ratio into the equation to change the swing feel. A value of 0.5 is straight timing while 0.67 is basically a triplet-swing. Values of .58 or .6 start to sound like a more relaxed swing similar to what I’d get from the TR-909 which can swing on its own.

Therefore, I need to get the MIDI Clocks the moment they come in to calculate an accurate tempo. Then I’ll need a PLL to keep the Mega2560 in sync with the MIDI Clock. I’ll then need a timer-based interrupt to trigger the Sync pulses based on the current ratio. Oh, and manage to update the LCD, get new values from the hardware controls, and process additional MIDI messages during the in-between times. Maybe I should just get separate Unos for each of these functions! Lord knows they’re not expensive at all.
And because of their low cost, I see myself doing all sorts of Arduino-based stuff. Electronic gadgets that seemed too complex to make years ago are now much simpler. I plan on making an EL-Wire sequencer for Fusion Festival coming up at the end of June. Fusion will be the closest thing to Burning Man I can find here, so I want to go all-out. I’ve seen 8-channel EL-Wire controller boards for Arduino so it should be a no-brainer project. In fact, the hard part will probably be managing the EL-Wire itself—figuring out how to affix it to clothing, my tent, bike, or whatever else I feel like. I’d like to get some sort of microphone input for the thing, too, so I could make the EL-Wire respond to audio…that would probably be the most complex part since I’ve never even researched audio-on-Arduino before. I’m hoping that someone makes a little board that can just give me an analog level based on sound pressure levels. I don’t need to do any hardcore DSP. It would just be nice to get the EL-Wire to pulse with the beat.

Dude, with how cheap these Arduinos are, you should totally pick one up to play with. The Uno is something like 25 Euro so I imagine a Uno would cost less than $30. The IDE is free, and just last night I figured out how to use Xcode to compile and upload the firmware to the Arduino. That’s going to make this project much easier, I believe, since things are likely to get hairy as I start interfacing with the timers and interrupts on this microcontroller. If you want, I can show you how to set it up, too—I’ve got template projects I could send to you that are ready-to-go. You just need to get the Arduino IDE (so you can get the core libraries) and the AVR Cross-tools for compiling to the Arduino from Xcode. It also comes with AVRDUDE for doing the device update. It’s slick!