Red Echo

April 13, 2011

Rhythm Robot PCBs arrived

April 12, 2011

Interesting, albeit cryptic, outline of common failure patterns in software development teams, with some quick advice on how to manage your way out of each problem. I haven’t dug around much on the rest of the site but it seems like it’s a fairly practical sort of thing and not just a collection of buzzwords.

April 3, 2011

Dave Smith (of Evolver fame) and Roger Linn (of the LinnDrum) have collaborated on a new analog drum machine, the Tempest:

Dave Smith Instruments today introduced Tempest, a new analog drum machine, at the 2011 NAMM Show. Tempest is a collaboration between Smith and longtime friend and fellow instrument designer Roger Linn. […] Each of the 6 analog voices has 2 analog oscillators plus 2 digital oscillators (with a large bank of included samples), Dave’s classic analog low-pass filter with audio-rate modulation, an additional high-pass filter, analog VCA with feedback, 5 envelopes, 2 LFOs, an extraordinary variety of analog modulation routings, and stunning sonic quality, warmth and punch. […] Two pressure- and position-sensitive Note FX slide controllers permit real-time recording of note or beat-wide sound parameter changes into the drumbeat as you play. For example, record simultaneous filter frequency, tuning, envelope decay and pan changes for each note, or control similar parameters affecting the entire beat.

April 1, 2011

This paper finds an inverse correlation of commute length to overall life happiness – Stress That Doesn’t Pay: The Commuting Paradox:

People spend a lot of time commuting and often find it a burden. According to economics, the burden of commuting is chosen when compensated either on the labor or on the housing market so that individuals’ utility is equalized. However, in a direct test of this strong notion of equilibrium, we find that people with longer commuting time report systematically lower subjective well-being. Additional empirical analyses do not find institutional explanations of the empirical results that commuters systematically incur losses. We discuss several possibilities of an extended model of human behavior able to explain this ‘commuting paradox’.

March 31, 2011

Super awesome inspiring mini-presentation: How to Steal Like an Artist, and 9 Other Things Nobody Told Me:

All advice is autobiographical.

It’s one of my theories that when people give you advice, they’re really just talking to themselves in the past. This list is me talking to a previous version of myself.

Your mileage may vary.

1. Steal like an artist.

Every artist gets asked the question, “Where do you get your ideas?”

The honest artist answers, “I steal them.”

March 30, 2011

Why I Like Mercurial More Than Git:

The tools are very similar, and many of the distinguishing differences come down to a matter of taste in my opinion. […] The big difference, the deal-maker for me, is in how each tool goes about meeting the fundamental requirement for any version control system: how it handles source code merging.

March 28, 2011

Right, so, what have I been up to lately?

I spent most of March in a cabin up near Whistler, sick with a flu, or both. I didn’t do as much skiing as I had hoped to, but a quiet cabin in the woods with a fireplace is not a bad place to laze around and get over a flu. I also brought a formidable array of computing hardware and spent a lot of my relaxation time writing code. Some of this was actual day-job work – I brought along the dev boards for my current project – but a fair bit of it was Radian work. In particular, I made solid progress on the two indexed-container objects, map and array.

Most of my time back in Seattle has gone into the ALTSpace project. We have a very substantial sewing workspace, a reasonably well-equipped machine shop, and a rudimentary electronics workbench. There’s a lot of sorting and organizing left to do, and we haven’t even started on the welding room, but it’s coming together. We still don’t have Internet access there yet, but someone who knew what he was talking about took a look at our telecom panel yesterday and figured out what needs to happen next.

I’m still picking away at the next Rhythm Robot prototype. I have finished the layout for the control panel board, which is by far the most complex electronic object I have ever attempted to build, and have actually printed and assembled the MIDI & power daughterboard. I have not yet had time to test the MIDI interface yet but the power regulator works exactly as it is supposed to. The logic board, based on the STM32 Discovery, still needs a fair bit of LED multiplexing circuitry, but I don’t need to finish that in order to make progress on the main control panel and the rest of the hardware needed to make this project go.

March 22, 2011

ARM-Utilities offers a download/upload/debug tool compatible with ST’s proprietary ST-Link protocol, otherwise usable only on Windows.

Later we decided to switch to the more powerful ARM processor, and selected the inexpensive STM32VLDiscovery board as our core module. We were dismayed at the very limited Windows-only support and the concomitant requirement to use a heavyweight GUI for every development activity.

These utilities, libraries and header files were the result of our desire for an equivalent quality ARM development environment. Especially a simple development, build and delivery toolchain. We not only wanted to develop the code, but archive it and have others use, modify, compile and download it with the same ease as with the AVR.

March 21, 2011

Simple, clear, well-written introduction to Pratt parsers

If recursive descent is peanut butter, Pratt parsing is jelly. When you mix the two together, you get a simple, terse, readable parser that can handle any grammar you throw at it.

Pratt’s technique for handling operator precedence and infix expressions is so simple and effective it’s a mystery why almost no one knows about it.

I would guess that it’s overlooked because the programming tools world is still largely convinced that automatic parser generators are something more than a dead end. People who don’t know any better see all the emphasis on parser generators and conclude that parsing must be some kind of inhumanly difficult, heinously complex process far beyond the capacity of an unaided human mind.

March 1, 2011

Clump is a program designed to replace makefiles. It builds C programs in what the author describes as “the most intelligent way possible”, to wit:

– Determine which C files need compiling by analyzing header include
dependencies and checking timestamps on the .o, .c, and .h files.

– Determine which C files are main programs by looking for an “int main”
declaration.

– For each main program, determine the exact set of .o files that need to
be linked together to build an executable file. It does this by tracing
the header dependencies in a recursive manner (transitive closure). […]

– Determine which system libraries need to be linked into a program
based on any system includes. For example, if a C file says
#include , then clump will know to put “-lcurses” on the
link command line. This is all configurable in the clump.ini file.

February 25, 2011

Computer Name List

Computer Namer is a big list of names people have chosen for their computers, with a little like/dislike popularity scheme. Flip through looking for ideas, or look at the top-10 lists for the best and worst.

Dependency Injection Demystified

This author basically had the same reaction to this idea of “dependency injection” that I did:

When I first heard about dependency injection, I thought, “Dependendiwhatsit?” and promptly forgot about it. When I finally took the time to figure out what people were talking about, I laughed. “That’s all it is?”

February 24, 2011

I spent a little while last night whacking together a simple web site for the new shop. There’s nothing much there yet, but it’s a start:
airlighttimespace.org

February 16, 2011

Ava and I have moved into our new home. We did most of the work in one big push on Sunday, with a lot of help from Erin and Shane. It was a solid day of hard labor and I’m still trying to catch up on rest.

Ava has been working hard getting everything sorted out. The bedroom and bathroom are all tidy, and the storage closet is full of neatly arranged shelves and stacks of bins. We have almost no living room furniture and the office is nothing but heaps of books and boxes, but it’s a good start. It feels happy and homey. Ava seems to be just about glowing with contentment.

The shop project is on the edge of success at last. We’ve collected the money, set up a business account, and signed the lease: now we are just waiting for the landlord’s EFT to go through so he can give us the keys. We should be able to start moving in on Saturday.

February 11, 2011

The Maple IDE is a fork of the Arduino IDE, designed to provide a similarly smooth development experience for LeafLabs‘ line of STM32-based development boards. While the Maple IDE can’t program the STM32 Discovery board directly, due to the STM32F100’s lack of a USB port, one user on the LeafLabs discussion forum has figured out how to use the Maple IDE to build programs for the discovery board which can then be uploaded using stm32loader.py.

February 10, 2011

Here’s a decent little Hello World for the STM32, including makefile.

As a musically inclined nerd in the ’80s, I once tried to play what I called the “Startup Song” on a piano: the sound of the floppy disk drive seeking from place to place as the ol’ Macintosh Plus started up made a distinctive and recognizable melody. This video goes much further: it is Bach’s Toccata in D minor performed on an organ made from four floppy-disk drives. The performer has rigged them up with a microcontroller and a MIDI interface so that the seek sound generates usable musical pitches.

February 8, 2011

Douglass Rushkoff is organizing a conference to be held this October with the aim of getting past the current hierarchical limitations of the Internet and developing something new, something decentralized, something subject to no central authority:

Lately, however, what’s wrong with the net has become quite crystalized for me. It started with the corporate-government banishment of Wikileaks last year, and reached a peak with Egypt shutting off its networks to stave off revolution. The Obama administration seeking the ability to do pretty much the same thing in the US, Facebook’s “sponsored stories,” and the pending loss of net neutrality don’t help, either.

Here on Shareable, and then again in an OpEd for CNN.com, I suggested we “fork” the Internet – that we accept the fact that the net is built on a fundamentally hierarchical architecture, surrender it to the corporations who run it, and consider building something else for ourselves.

This “Contact” event sounds like it is designed to get together people who are interested in all the various peer-to-peer / mesh networking / open routing / open social-graph projects and see what kind of cross-pollination can come about. I might go to this.

How to build a Mac OS X-hosted GCC cross compiler for AVR or ARM architectures.

February 7, 2011

The landlord has finally finished drawing up the lease paperwork for the new shop space. I still have to go set up a bank account for the LLC and get various other paperwork signed, but it’s very close now. We should all be able to move in this weekend.

At the same time, Ava and I are moving out of Sunrise. We have rented a cute little two-bedroom apartment of our own, located in the same complex as the new shop space. It’s small but nice, with hardwood floors and classic trim. We’ve been living and working in one big room, which sounds nice in a sort of romantic bohemian way but hasn’t actually worked out that well. With the new arrangement, we’ll be able to separate the art mess from the rest of the living area, Ava will have a quiet private place for herself, and I’ll have lots of room to host work parties and tackle big messy projects of my own.

February 1, 2011

Research on the feasibility of ad-hoc 802.11 wireless mesh networks: it’s not encouraging.

We also show that the traffic pattern determines whether an ad hoc network’s per node capacity will scale to large networks. In partic- ular, we show that for total capacity to scale up with network size the average distance between source and destination nodes must remain small as the network grows. Non-local traffic patterns in which this average distance grows with the network size result in a rapid decrease of per node capacity. Thus the question “Are large ad hoc networks feasible?” reduces to a question about the likely locality of communication in such networks.

January 31, 2011

gostm32 is a single-topic blog about using an STM32Discovery development board with open-source dev tools.

The STM32Discovery is an absurdly inexpensive breadboard-compatible product bearing an STM32F100RB running at 24 MHz. It’s not the hottest Cortex-M3 chip on the block, but compared to SparkFun’s Cortex-M3 board or the LeafLabs Maple, which each use an STM32F103RB, this appears to be a very good deal indeed.

The Serval project has successfully implemented 802.11-based mesh wireless communication between Android phones. This project sounds interesting: they have similar goals to what I was trying to do with the “walkie-textie”, only they’re doing it with stock phones.

January 30, 2011

Swedish guy hunts down and destroys hydrogen-filled balloons with a radio-controlled, roman-candle-armed, camera-equipped tricopter: a video of rarely-paralleled awesomeness.

January 29, 2011

Planning for the new shop space is taking up much of my free time. I am increasingly certain that the project is going to be a success: the location is about as good as it could possibly be, the group has a broad-but-overlapping array of interests, and the people involved are all getting along smoothly.

Mike T. and I went to a garage sale in Fremont this morning: an old metal shop was closing down and selling off their tools. We decided we didn’t really have room for the plasma table, and none of the welders really fit our needs, but we found a good assortment of hand tools and a couple of classic metal power tools. The prize was a $20 bench grinder. It’s all sitting at the Rocket Factory for now, but it’ll all end up at the nameless new space sometime in February.

January 22, 2011

I had dinner with Martin M. this evening. I hadn’t seen him in a while and called him at random last night, thinking it would be nice to catch up. We had a nice talk over beer at Smith, on 15th; he’s enthusiastic about his new(-ish) job at Google, and we traded speculations about the future of the computer industry.

After getting home I spent some time working on my electronic music device. I’ve stepped back from the all-in-one drum machine idea; it’s definitely the right direction for a commercial product, but I am daunted by the long list of unknowns I’ll have to deal with to get there. For the moment I’ve cut the box in half and am working on another Rhythm Robot: this one a complete sequencer, including the features of the Steadyrocker metronome gadget. I’ve designed the control layout, and am now working on the best way of connecting 92 individual LEDs, 10 7-segment LED digits, 12 lighted buttons, and 6 rotary encoders to an ATMega328 controller. I’m sure there will be a handful of PCF8574 I2C IO expanders in there, and perhaps some TLC5925 LED drivers too. The latter only seem to be available in surface mount packages, though, which scares me.

January 21, 2011

Mayhew Labs is offering a Rotary Encoder LED Ring: a PCB with surface mount LEDs and a SPI-controlled TLC5925 driver chip. It’s set up so that you can either mount the encoder on the PCB itself or use a panel-mount style encoder and screw the board onto the encoder’s shaft. Unfortunately it is marked as “not available yet” with no indication of price or availability….

January 18, 2011

Tribler is a BitTorrent client which includes peer-to-peer resource discovery and search: that is, you don’t need a central tracker, and you can search among torrents advertised by other Tribler users. It’s available for Windows, Mac, and Linux. They have some interesting ideas on decentralized spam suppression; I wonder how well it will all work in practice.

I have no idea whether the implementation is any good, but the concept is interesting: a peer-to-peer VPN that self-configures via your XMPP contact list.

It is apparently now going to be possible to write apps for Android without having to use Java. I can’t imagine why I would want to write a mobile app in the first place, but Android has definitely come to seem like the most appealing of the mobile app platforms, and not having to use Java is a nice bonus.

I imagine I can understand now how the old mainframe programmers must have felt about the rise of the personal computer. All around me the computing world has been going crazy over phone apps, and I just don’t care. What can these tiny little platforms possibly offer me, all locked down and controlled by evil megacorporations? They’re just toys! Give me a real computer, and get out of my way with all that appstore nonsense!

And yet here they are, apparently taking over the world.

January 14, 2011

Rhythm Robot control panel layout, revision 5. The box I’ve selected is 7″ deep by 11″ wide, with a 1/2″ lip around the top edge. The boxes with the rows of dots along the top and bottom are 7-segment LED digit displays; the squares with three dots underneath are rotary encoders (knobs); the smaller boxes with six small dots in them are lighted pushbuttons; the small vertical rectangles are LEDs. Not shown are the rings of 3mm LEDS around all but three of the encoders.

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