Finally there is some positive progress to report on the latest ORB. The circuit boards have been designed and ordered (thanks, as usual, to Shane @ GoldPhoenix) and the CNC milled aluminum circuit board supports are completed and in hand. Many thanks to David Gotter (bio) and Rob Klaus of D&R Machine for their excellent work and patience in helping me through my first design for CNC fabrication. Check out David's other project, Further OPTIONS developing "innovative vehicle entry systems for wheelchair-bound individuals". D&R offers extremely capable and affordable machining services and is open for long-distance business via Internet and mail order. Contact them for your next project.
I'm also very excited to say that this piece has become a three-generation project. In addition to my collaborator and father, Ron Sears, my grandfather Jim McCoy is contributing his masterful woodworking and finishing skills to this project. Everything is in line for a beautiful piece.
This week, my biggest test thus far will begin: a massive soldering undertaking centering around 320 surface mount RGB LEDs, and a matching 960 resistors in 0201 packages. That's 0.024" x 0.012" for those of you keeping score at home. In addition, the design utilizes sixteen 80-pin PIC microcontrollers and a slew of other circuitry. If I can still focus my eyes well enough to see the audience at thesis week, I'll call it a victory. Starting later this week, when the parts and boards arrive, I'll be posting photos and possibly video of the assembly process right here on this blog.
For now though, here's a peek at one of the pair of aluminum board mounts fabricated at D&R Machine. There's much, much more to come, culminating in an initial exhibition at the ITP Thesis Week and Spring Show, on May 3 and May 8-9, respectively.
On the front page of nytimes.com tonight is the obituary of Kurt Vonnegut, novelist, playwright, poet. It seems that I must be one of the last people on Earth to have not yet read a Vonnegut novel, but I was struck by the dark and somehow inspirational beauty of this final passage of his poem Requiem.
From Requiem, A Man Without a Country:
When the last living thing
has died on account of us,
how poetical it would be
if Earth could say,
in a voice floating up
from the floor
of the Grand Canyon,
'It is done."
People did not like it here.
The circuit boards are here, having made the trip from the GoldPhoenix fab in Wuhan, China to Manhattan in about 36 hours. The parts are here, a day early in typical DigiKey fashion. Now it's time to start burning some flux. Before I do, though, here are a couple of quick photos from the unpacking process.
The virgin board. I have a pair of these to solder, with at a guess maybe 3-4k SMD pads each. It looks like I won't be seeing much daylight for the next week or two.
If you've ever wondered what $2k in DigiKey parts looks like, wonder no more. Not all that impressive on the surface, eh?
I had a need recently to convert a .bin/.cue CD Image pair to .iso for mounting on OSX. I was considering writing a quick utility to handle the task, but in the process of researching the file formats, I found BinChunker, a GPL-licensed piece of code that does exactly what I need, simply and directly. The official site has the source code and RedHat RPM's, but if you are on OSX, I did a quick compile of the latest version which you can download here.
Once you download the utility, issue this command from a shell prompt in the directory where you downloaded the file:
sudo cp bchunk /usr/bin/
This will copy the file into a location where the system can find it at will (a.k.a. the path). Then, to convert a .bin/.cue pair to a .iso, you can issue this command:
bchunk myinputfile.bin myinputfile.cue myoutputfile
Short, sweet, and simple — and lightweight too, weighing in at only 20k.
UPDATE: As commenter Frederik has pointed out, this can give a permission denied error if your user account does not have execute permissions on the file. Execute this command after copying the file to /usr/bin/ to solve this problem:
sudo chmod a+x /usr/bin/bchunk
If you are getting a not found error, make sure that /usr/bin/ is in your path. To check this, type
echo $PATH and look for /usr/bin/ in the result. If it isn't there, type
sudo nano /etc/profile and add
/usr/bin; to the
PATH=... line. Then press
CTRL+x followed by
Y to confirm and the enter key to verify the filename to save and exit nano. Then execute
source /etc/profile to refresh the path.
After a couple of days of intense soldering, the first major task is complete. The 960 0201 LEDs are all in place. It's funny, after two days of work, the boards look almost entirely the same to the naked eye. While I can barely focus on the screen to write this (seriously — now I understand what it's like to need glasses, if thankfully temporarily), the upside is that after soldering almost 1k 0201 parts, the 0402 package parts look like bricks and are easier than ever to handle. In any case, I'm here to say that it is very possible to hand solder 0201 parts. Time to go clear the head and get ready for another day of soldering tomorrow. In the meantime, here's the view from the soldering station:
Just under 100 hours to go until the first display of the ultraORB at my thesis presentation, Thursday, May 3 at 8:40pm. There is still a lot to do, but things are moving forward. 16 microcontrollers are interfacing with 128MB of onboard flash memory and my laptop through 8 dual-channel USB interfaces. Now it's on to wrapping up a few loose ends and then soldering the 320 RGB LEDs. Then on to the first spin. Stay tuned...
For those of you who haven't been following along with the in-person presentations, here's a little clip of video that was shot about a month and a half ago, showing the ultraORB concept in action. This is a demo and concept test with 4 single-color LEDs — the version due to be presented this coming week will have a total of 320 tri-color LEDs under microprocessor control to create a truly three dimensional persistence of vision display.
Here's a view of 1/8th of the final assembly with LEDs in place. 280 LEDs to go.
Resting atop the PCB is the CNC machined aluminum board mount, holding in the foreground one of the four DC-DC stepdown converters from short-circuit.com. The board mount is topped by the three conductor commutator assembly, handmade from readily available materials and a few custom laser cut plexiglas spacers. The commutator mates with a set of brushes to deliver +15VDC, GND, and a timing signal from one of a pair of hall effect sensors mounted on the assembly rotating about the vertical axis (each quadrant of each PCB also has its own hall effect sensors to sense rotation about the horizontal axis).