Category: Uncategorized
Modkit Micro Alpha
Modkit Micro Alpha does not run on Ubuntu 12.04 64-bit without the user moving some directories around and installing ia32-libs.
It also does not save projects more than once per launch, or compile code at all, on Ubuntu or Mac OSX.
I appreciate that the point of Modkit’s Kickstarter campaign was not to sell a finished product, but to get the money to produce one. That said, people who have paid money for a thing may want that thing to work. Modkit is now in the uncomfortable position of having sold the moon, and being expected to deliver it.
ToyBrain V2 Ordered
I’ve ordered the boards for the second version of the ToyBrain project. These boards are smaller than the originals, and should correct most of the problems (swapped TX/RX lines, put the ICSP header in right, etc.) I’m planning to outfit them with ATMega328s.
If these work and are all correct, the next version will be done in black, possibly with gold for looks. After that, perhaps I’ll make a kickstarter of it and see if I can’t sell a few boards.
FFMPEG recipes
ffmpeg -y -i video.avi -vframes 1 -ss 00:00:10 -an -vcodec png -f rawvideo -s 320×240 frame.png
Extract the frame at 10 seconds into the video file video.avi, resize it to 320×240, and save it to frame.png.
Conductive tape for biosignal acquisition
If you want to monitor electroencephalographic (EEG, electrical signals from the brain) or electromyographic (EMG, the electrical signals from moving muscles), you need to use electrodes to get the signal. The electrodes are generally not reusable and are kind of expensive. They usually run somewhere from $0.70 to $3.00 each, although the 3M Red Dot electrodes are much cheaper. The electrodes usually use a conductive gel surrounded by a ring of non-conductive adhesive, which makes them large and difficult to put close together.
It seems likely to me that you could use electrically conductive tape to improvise contacts of any size and shape. The adhesive probably isn’t tested for use on humans, and the conductive element is sometimes something that people have an allergy to, like nickel or silver, but it could be sufficient for self-experimentation for quick hacks. It would also be an order of magnitude cheaper
Conductive tape: http://www.tedpella.com/semmisc_html/semadhes.htm
Cheapo Red Dots: http://www.amazon.com/Red-Dot-Monitoring-Electrodes-Diaphoretic/dp/B000TBSAH0/ref=sr_1_1?s=industrial&ie=UTF8&qid=1336146625&sr=1-1
Unusual Data Visualization Tools
The Boston Marathon is visible in Google Maps’ traffic view. The road is closed for the runners, and the runners are going slow, at least relative to a car, so they show up as a huge traffic jam on the race route. All the other roads are in good shape because Race Day/Patriots’ Day is a state holiday, and so everyone is home from work. It probably also helps that it’s a gorgeous day out, and so no one wants to be in their car.
Dumpster Diving
My neighbors are throwing away a pair of Swiffer vacuums. Combined with my ToyBrain boards (when they arrive), those will make some sweet housecleaning robots.
Gorilla Glue Allergy
I used Gorilla Glue in several of the projects that I worked on last week. I’ve used it before without incident, but I think the continuous exposure over the week was enough to trigger a reaction. I got symptoms like dyshidrotic eczema, that is, tiny blisters filled with clear fluid and surrounded by raised, itchy, red bumps. On top of that, anywhere that I had already been having an allergic reaction (poison ivy and mosquito bites) flared up with its own constellation of welts. My fingers also swelled up enough to make it difficult to make a fist.
I’ve been treating it by taking dyphenhydramine (benadryl) regularly, and applying 1% hydrocortisone ointment in the morning and evening. The ointment is kind of a greasy mess, so I wear hypoallergenic chloroprene gloves after putting it on. It is gradually getting better, especially on the areas that get the most hydrocortisone coverage.
From now on, though, I’m going to put the gloves on before I use the glue, so I don’t have to use them for days afterwards.
Xybernaut Head Mounted Display to VGA hax!
I have a Xybernaut Xyberview HMD, which originally connected to a Xybernaut MA-V or MA-IV wearable computer. Xybernaut went out of business after some questionable corporate shenanigans, but while they were around, they made a solid product. Unfortunately, they used a custom, or at least obscure, connector to hook that solid product together.
Thanks to the Wayback Machine, I’ve found the pinouts for the connector, and wired mine up so that it takes a standard VGA input. I also built a power supply for it, because it needs 5V and 15V power. The power supply takes 15V from a laptop power brick and drops part of it to 5V while also providing a 15V pass-through. I used a switching regulator, because otherwise I’d be dropping 10V at unknown current as heat.
I initially had the red and blue lines of the VGA connector crossed, but I think that is because they are crossed in the instructions that I found. My corrected pinout is below. If you happen to actually be equipped to do this hack, please do let me know if I made an error, and your terribly expensive, extremely obscure hardware from the mid ’90s somehow fails to work.
The HMD connector has two rows of pins in a connector that looks a little like a miniature Centronics connector. Assuming the longest edge of the connector is on top, there are 13 pins in the upper row (U1-U13) and 13 pins in the lower row (L1-L13).
Wire colors are described as the color of the wire, the color of the mark on it, and whether the marks are sparse. So Yellow/Red (sparse) means a yellow wire with a red mark on it that is less dense than the wire described as Yellow/Red. You’ll know it when you see it.
Signal Name Xybernaut Wire Color VGA Pin Red L4 Pink/Red (sparse) 3 Red ground L3 Pink/Black (sparse) 6 Green L2 Yellow/Red (sparse) 2 Green ground L1 Yellow/Black (sparse) 7 Blue U14 Gray/Red (sparse) 1 Blue ground U13 Gray/Black (sparse) 9 H Synch L6 White/Red (sparse) 13 V Synch L7 White/Black (sparse) 14 Synch ground U10 Pink/Black 10 +5V U1 Gray/Red +5V U2 Yellow/Red +5V U3 White/Red +15V U5 Pink/Red Digital ground L13 Yellow/Black 5 Digital ground L10 Gray/Black Digital ground L5 White/Black Analog ground U8 White Headphone out L12 Pink Mic in U7 Yellow HMD Sense L8 Gray 11
I connected the Gray/Black and White/Black wires to the ground of my power supply, the Yellow/Red, Gray/Red, and White/Red wires to 5V, and the Pink/Red wire to 15V. The display powers up, and I can drive it from my laptop using 640×480 resolution at 60Hz.
Unfortunately, none of this hacking changed the fact that wearing an HMD makes you look like a cyborg from space.
Neural Net book
For a book on a kind of dry subject, this book has an oddly humorous tone:
“It is also interesting to rotate a frog and notices that his eyes try to maintain their orientation up to some maximum angle at which time the frog will close his eyes, giving up the attempt at computing the appropriate adjustment of the visual input. Try not to let anyone see you doing these experiments”
“If a hole is punched in the visual cortex, V1, the only apparent deficit is a hole in the field of view… There are anecdotal records of people receiving damage to this part of the cortex. They report seeing President Bush’s thousand points of light.”
“At a recent neural network conference, Minsky tried to clear up the misconception that he was the devil.”
That last one is because Minsky wrote a proof that single-layer perceptrons can’t do the XOR operation, and funding for neural networks dried up for years. This made him unpopular with the people who had been getting that funding.
Lex and Yacc syntax highlighting for Nano
There’s not a lot to them, but it’s better than anything I could find on the Internet. The real key feature is a line in the yacc syntax highlighting file that marks whitespace at the end of lines. Since yacc/bison are sensitive to that, it’s good to be able to see it.
Nano syntax highlighting for yacc or bison:
## Syntax highlighting for yacc/bison input files syntax "yacc" ".y$" color red "%[a-zA-Z0-9]*" ## String highlighting. You will in general want your comments and ## strings to come last, because syntax highlighting rules will be ## applied in the order they are read in. color brightyellow "<[^= ]*>" ""(\.|[^"])*"" ## This string is VERY resource intensive! color brightyellow start=""(\.|[^"])*\[[:space:]]*$" end="^(\.|[^"])*"" ## Comments color brightblue start="/*" end="*/" ## Visible space at line ends color green,green "[[:space:]]+$"
Nano syntax highlighting for Lex or Flex:
## Syntax highlighting for lex/flex input files syntax "lex" ".l$" color red "%[^[[:space:]]]*" ## String highlighting. You will in general want your comments and ## strings to come last, because syntax highlighting rules will be ## applied in the order they are read in. color brightyellow "<[^= ]*>" ""(\.|[^"])*"" ## This string is VERY resource intensive! color brightyellow start=""(\.|[^"])*\[[:space:]]*$" end="^(\.|[^"])*"" ## Comments color brightblue start="/*" end="*/"
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