Meep in the Big City

I’ve been enjoying SourceTree as a way to keep track of changes at work, but it wasn’t obvious how to set up FileMerge to work with it.
Instructions:
1. Set the correct Developer path in the Terminal by typing

sudo /usr/bin/xcode-select -switch /Applications/Xcode.app/Contents/Developer

2. Under Preferences > Diff, set the merge tool to ‘Other’, the merge command to

opendiff 

and the arguments to

$LOCAL $REMOTE -merge $MERGED

3. ???
4. Profit!

I was recently accepted into the DorkbotPDX gallery installation at Styloid Process entitled “Connection & Suspension” with my first electronic art piece called “Conversation Piece”. My favorite kind of artwork is the kind that invites you to play with it. I was inspired by the last Dorkbot show a few years back, where there were lots of fun electronic toys, plus a gallery nearby that had kinetic artwork. I had observed a cooperative play that happened at Luz parties where two people would riff back and forth as long as there were enough inputs and visible output for multiple people. Knowing this, I had gone through several ideas before I reached the very simple tin can idea. I had the separate idea to make a USB tin can that you could use with Skype, but realized that it wouldn’t be practical for a gallery setting, especially with a computer, so I decided to make two tin cans that would be strung at opposite ends of the gallery, where two people would have to negotiate to communicate with each other.

The construction process was pretty arduous. I isolated the piece into its elements, which were the two tin cans and a central Arduino that would switch between the two. After reading two electronics books partway and building a dud of an intercom circuit, I went back to the source of the problem by heeding Jason from Dorkbot’s advice – build an amplifier.

I started with a bare circuitboard, an LM386, and the datasheet. I tried a few of the circuit suggestions in the datasheet and even accidentally built a radio for an hour. I did run into a strange problem in which I found out the AW5K relay’s datasheet was inconsistent with how the relay actually worked, so once I flipped some wires around it was fine. I added a button to switch the relay manually since I didn’t have the tin cans ready. The gain was crazy and causing my cheap speakers to have a high-pitched beep tone, so I replaced the single resistor with a 10k potentiometer (the kind of knobs you find on volume switches).

Next was constructing the can. I used a Dorkboard connected to the insides of a Wii Nunchuck that I took apart. I tried using Todbot’s code, but since there was no position data and the code was a mess, I scrapped it for a thrice-adapted header file. I simply read the position from the can and had the Dorkboard set the outgoing pins high or low based to show that it was ready to talk and to listen, and have the Arduino between the two cans decide which one gets to talk or listen.

The middle part was the hardest. I used CAT5 (networking) cable to carry the power and signal on each can to the central Arduino, which was also connected to the breadboard and was carrying 5 volts of power to the whole circuit. The relay was then connected to a Darlington transistor and then wired into the Arduino. I’m still uncertain of the approach in logic I took, but you can see the code for yourself.

I am considering reworking the hardware and software after I take it out of the gallery, and finishing my original USB tin can idea as well. Overall, I am satisfied with the end result, and proud that I taught myself basic electronics in two months.

I’m co-teaching the Induction this year, showing people how to construct their own Dorkboard. If you are interested in making lights blink, pigs fly or other assorted electrical craziness and live in Portland, come on down!
RSVP at Tempus Dictum. Some of the proceeds go to feeding you pizza for lunch.

Hi everyone. On the tail of my hourly comic, I started drawing a bit more. It’s not amazing but I am confident that in five years I might become a decent picture-drawer. Bonus: guess what font I used for the main text!

In an attempt to get myself to write, I am going to purge whatever writing thoughts are floating about, no matter how old they are, and barfing them up for this blag-thing.

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There is a bustling town not the size of a city, but larger than a village where more ordinary people live. In this town there is a street more descripted than another nondescript avenue or road, with bits of cobblestone peaking out beneath the cement. On this street there is a greengrocer frequented by the residents of the shops on this road, and the passers-by that walk up and down before returning to work. And at the back of the greengrocer behind the tins of sardines and aceptic containers is a little girl named Ben. Today she is looking more presentable than you or I, as she is freshly washed and her dress newly mended with a gawdy tie that a businessman was desperate to get rid of. Pulling her hair back with a kerchief, she smiles at the businessman’s wife, clearly noticing that the tie on the dress was the same tie she gave to her husband for his birthday. The businessman’s wife frowns, the wrinkles struggling to appear on her face, and thinks a nasty thought about the circumstances regarding this imp and her husband.

“Hi ma’am! The beets are on sale – 75 cents a pound!” Ben points to the sign cheerfully, then pins on a small nametag reading “Ug8″. The businessman’s wife widens her eyes defiantly at Ug8 the Imp and storms off, muttering horrible things that, in passing, do not sound like English words or phrases at all.

Luz is a cool music visualization program that is currently only operational on Linux. I have finally figured out the steps to run the display app (luz_performer.rb) using MacPorts. This guide is a work in progress.

You will need to install XCode 3.1, otherwise the tiff library complains and I haven’t found a way to get past that.

Step 1

Install ImageMagick via MacPorts. I’ve tried to compile from source and it never seems to work right. Install the rmagick gem afterwards.

Then install libsdl +universal if you’re running an Intel-based Mac. It will default to PPC. Go ahead and install libsdl_mixer, libsdl_image, etc. Also install the rubysdl gem.

Step 2:

Next, you will want to download rcairo and install from source – there is a patch that fixes the “Flag option -o has already been seen!” error you will get if you try to install from the normal gem repository.

All those commands:

sudo port install ImageMagick libsdl +universal libsdl_mixer libsdl_image cairo
sudo gem install rmagick rubysdl

Step 3

You will need to install Bazaar to download Luz from the repository. There are installers on the website, or you can type sudo port install bzr in the Terminal.

Step 4

Download Luz by typing:
bzr co --lightweight lp:~ian-mcintosh/luz/trunk luz
DO NOT follow the installation instructions on the website — those are for a computer running Linux.

Step 5

Download and untar sdlboot. If it doesn’t work the first time, run the Makefile and it might magically work. I put main_hook into luz/trunk/ and ran the following command from the sdlboot directory:
./sdlboot ruby -r rubygems ../../luz_performer.rb path to performance

If you have problems or questions, leave a comment.