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Posted by Jack Crossfire | May 09, 2015 @ 07:54 PM | 3,064 Views
There is somewhat of a desire to build a fully tricked out Pixhawk based copter from scratch, make the electronics from scratch, make a custom radio module for it out of an 8 year old XBee, & make a brushless gimbal for it. It would be just like the original plan to build a copter around Rotomotion's code fragments, but it would work.

The problem is the severe limitations of hobby grade copters are still around, no matter how many billions every quad copter company is now worth. There were a few issues in a recent video:

Flying the DJI Inspire 1 Quadcopter with Adam Savage (10 min 38 sec)

Modern radios continue to require line of sight. The radio & limited battery life still limit them to flying in a cone directly overhead. All quad copter videos look the same. They fly 1 mile horizontally, then have to turn around.

Navigation is a lot better, but it's still not possible to make a timelapse of a quad copter by having it stand perfectly still. They still look out of control in windy environments. They still can't be flown reliably enough near people & property, eliminating most of their use. They're still far too dangerous to be the household objects they're now marketed as.

Another video showed how useless optical flow continues to be, despite being the latest thing. It still required constant attention to keep from drifting away. Low altitude continues to require constant attention, as the barometers still drift.

Hands-On with DJI&#
...Continue Reading
Posted by Jack Crossfire | May 07, 2015 @ 11:17 PM | 2,734 Views

It was finally time to tear down this 15 year old beast. It was intended for verifying NTSC compliance, but NTSC was short lived. It was used for maybe an hour upon arrival, in an unsuccessful attempt to receive local TV stations, then was briefly valuable in burning a DVD after 7 years, then never again for 8 years.

The innards are revealed for the 1st time.

...Continue Reading
Posted by Jack Crossfire | May 03, 2015 @ 06:15 PM | 3,694 Views

It has become quite clear that not being able to take it all with you is part of daily life, even for stuff that used to be considered valuable like electronics. It's especially hard to get rid of something that was $5000, but is now worthless. The problem is a large mass of antique computers has accumulated over 20 years, which is unaffordable to keep in an age of $10,000 rent.

The dual 2.4Ghz Opteron was $5,000 when it was new & served from 2006 - Summer 2010. If it wasn't for a misdiagnosed power supply issue, it would still be in use. Now, it's long been outdone by the laptops.

The dual 2.5Ghz Opteron was unreliable & slower than the 2.4Ghz, because of a limited memory bus, but it served for a very long time.

The dual 1.4Ghz Athlon was a quick decision which ended up very low performing.

The dual 933Mhz Pentium III can be outdone by a $30 phone, but it was a fortune when it was new. It was the standard office computer in 2000.

There were still bits from a dual 450Mhz Celeron. It was a true miracle when it was new, the 1st SMP machine. The moment of inspiration for building it is still a strong memory of waking up 1 sunny day thinking it was time to go SMP.

There was a 166Mhz Cyrix which was slated to become a router, but now you can solder something like that from loose parts.

For a long time, the plan was either to boot them up again for embedded applications or recycle parts as needed. It...Continue Reading
Posted by Jack Crossfire | May 03, 2015 @ 01:35 AM | 3,766 Views
After a frenzy of activity lasting 2 days, the old dump which was home for 14 years & 6 months was no more. It was like everything that happened there never was, yet if I woke up there again & everything was in its old place, it would feel as at home as if the move never happened. Perhaps in a parallel universe, a fake test pilot still lives there & life continues as it always did. Just 4 months ago, everything seemed as if it was going to continue as it always did, forever. There would be another summer there, another XMas, another year of waking up in the same place, but it suddenly ended.

Posted by Jack Crossfire | Apr 18, 2015 @ 01:00 AM | 4,711 Views
It certainly wasn't the biggest government bungle, but the giant welding machine began to tilt immediately after it was built. There were rumors that it was shedding bearings.

3 months after it was built, it was leaning .06 degrees or 1/4" out of alignment at its highest point. The whole thing was torn down with plans to rebuild it, someday. In typical government contractor fashion, the swedish contractor was supposed to reinforce the foundation & just simply didn't. Tough beans.


Posted by Jack Crossfire | Apr 17, 2015 @ 12:09 AM | 3,873 Views

In a touching finale, the mangled engines & landing gear that someone worked his ass off to get working are revealed before the $60 million piece explodes.

There was a rumor that the mane engine can't throttle low enough to descend. They have to start the engine close enough to the landing pad to reach 0m/s at 0 altitude.
Posted by Jack Crossfire | Apr 15, 2015 @ 11:07 PM | 12,374 Views
CRS-6 First Stage Landing (0 min 23 sec)

After many ice obstructed videos from onboard the rocket, lost viewfinder videos from a chase plane, & partially visible gopro videos from the barge, it was the 1st watchable footage of a landing ever captured. It was most impressive by how hard it was to make the video & how far they continued with no footage of a previous landing to go by.

The final landing attempt was the most aggressive out of control fall, following by last minute suicide burn. The legs deployed 7 seconds before touchdown, while in previous videos they deployed 10 & 9 seconds before touchdown. If they used the more conservative approach of the past landings, it would have made it.

They obviously tried to stretch the fuel farthest with the least stable approach they could get away with, but it's not stable enough to recover from. They need a customer with an even lighter payload than NASA, but so far, NASA is the only customer willing to throw away enough upmass to get this far.

There are 2 more landing attempts this year, in the form of 2 more NASA missions.
Posted by Jack Crossfire | Apr 13, 2015 @ 12:22 AM | 4,003 Views
The blurry, shaky cellphone cams reveal a world of dead ends, buzzwords, & few practical demos. It's like a frozen moment in time when Goog glass just came out & everyone wanted to be bought out by doing a copy of that. 3 years after these concepts hit the kickstarter circuit, none ever became mass produced & all attention shifted to virtual reality goggles.


That guy loves joysticks & patents.

A reversion to the trackball, but with a pad instead of a ball, might get more mileage than either a joystick or a full pad.

ETAOI - a five key Android keyboard for phones and wearable computers (15 min 25 sec)
...Continue Reading
Posted by Jack Crossfire | Apr 12, 2015 @ 01:11 AM | 3,294 Views
So the idea came up of a simple commuter setup that would allow someone to type while standing up in a crowded train. The system would be compact & light enough to run down 1 mile of city streets. How could it be done as simply & cheaply as possible?

It amounts to 2 inventions that went absolutely nowhere: the virtual reality goggle & the wearable keyboard. Google glass would have been the ideal form factor, but it only did 640x360. No virtual reality goggle has ever been mass produced. Google cardboard might work, but would need a camera projecting outside video in a window. Maybe a new kind of goggle with no sides can be invented. The cheap phone is only 480x800.

The most effective keyboard leans toward a rubber thing. The rubber thing contains a full keyboard & touchpad. A different full keyboard & touchpad is worn on each side of the abdomen. If not a full keyboard, each side overlaps the other by a few keys. Maybe it could be a single rubber keyboard on the abdomen.

This amounts to a lot of money. Maybe there's an incremental step from the bog standard phone.

The average commuter stares at a phone screen, desperately trying to be entertained by what meager, meaningless news bites it can download between tunnels. Don't know what they did 30 years ago.

The mane limitation with this scheme is 1 handed or 1 fingered typing being extremely slow. What you need is a 3rd arm to hold the phone so both hands can type. If an arm can be designed, it conceivably simplifies the problem quite a bit. A simple arm to hold the phone combined with the abdomen keyboard might do the job.

Searches for wearable computing show a wasteland of vaporware stretching 5 years into the past. There's much more vaporware than the old days, showing how much longer vaporware can survive without making money than it used to.
Posted by Jack Crossfire | Apr 09, 2015 @ 11:57 PM | 3,331 Views
Free nuggets about lane following are few & far between. There are many nuggets about line following, but not lane following. This story was fascinating for 2 reasons


It was work my generation did when it was in college, with the tools available during our time. It was so primitive to modern eyes, yet it was the bleeding edge for someone living in that time. There was no GPS. Capturing video on a computer was nearly impossible.

The full text of their path following algorithm costs money, but there's a rough description


The key to their algorithm was a scanline intensity profile. It was done on a 30x32 greyscale image, on a 486. The scanline intensity profile was derived from a test of lane curvature. The lane curvature can be neglected, since the current issue is a straight path.

They captured the entire lane width, converted the trapezoid shaped path to a rectangle by widening & shifting farther rows horizontally. When making the rectangle shape, they made several images with the farther rows shifted left or right by different amounts. Then they summed each column in the rectangle image. The adjacent columns had the maximum differences when the shifting of rows matched the path's true position.

The sums of each column made up the scanline intensity profile. The scanline intensity profile when the vehicle was centered in the lane could be compared to the current scanline intensity profile to give its lateral offset. The current scanline intensity profile was iteratively shifted left or right until it matched the centered one.

They claimed better results this way than with edge detection. The key advantage was immunity to shadows, relying only on visual features running parallel to the road. This method does require training the algorithm with known scanline intensity profiles for a centered vehicle on different sections of road. There was another issue of cropping the image to where the path should be.
Posted by Jack Crossfire | Apr 08, 2015 @ 12:51 AM | 3,480 Views
2 years after building the 1st handheld 3 axis gimbal suitable for running


they're now ubiquitous, in a much smaller form factor, for a lot more money.

Tested: Feiyu G3 Ultra 3-Axis GoPro Gimbal (6 min 59 sec)

The modern Chinese versions of course, still haven't figured out the pan needs to be manually controlled by a joystick. The #1 market for brushless gimbals was not the quad copters they were originally sold for, but the single handed use they're just now starting to be sold for.

The other dead ends were the 2 handed James Cameron design & having the camera under the gimbal. After 2 years, they finally discovered the single handed stick design with the camera overslung was the way to go.

1 remarkable aspect is the gyros now calibrate without being perfectly still. No-one reviewing a gimbal ever asks how these things are accomplished, but years ago, it was the biggest question. Perhaps modern gyros are stable enough, their centers can be calculated purely by temperature.
Posted by Jack Crossfire | Apr 06, 2015 @ 02:43 AM | 3,381 Views

The construction is endless. Endless highrises as far as the eye can see are going up. The Yellen said let there be credit & at once there was infinite credit. It's the largest credit boom in all history, infinitely larger than 2007, infinitely larger than 1999. Dow 18,000 was just a dream when it hit 10,000 just 5 years ago & now 40,000 is just around the corner.

Rent here is now the highest in the world. $6000, $7000, $8000 & it rises every week. You can more cheaply build an apartment out stacks of money than make the amount of money required to rent it. The Yellen decreed without total employment, the money would continue to flow, forever.

Overnight, software became the new english. Almost every conceivable task now requires writing software, but instead of the software jobs spreading out to the industries that use them, the industries chased the software jobs to SOMA. Business minds have decreed software can only be written in SOMA, by formally trained programmers with Stanford degrees.

Every conceivable product is now being developed in SOMA. Food, medicine, clothing, pet furniture, mortgages, health insurance, payment schemes, cars, shoes, farms, movies, artwork, spaceships, everything that was once created in an entire country now requires software & can only be done in SOMA.

It's horribly inefficient, but up is the new down with infinite credit. Stanford graduates live in a different universe, now making over $400,000 their 1st year after college. That different universe is rapidly becoming the baseline to stay here. The time is nearing when those of us who can't keep up with the rent are going to have to move out. There's probably 2 more years left at 2010 era salaries, but if anything necessitates going back to school, it's going to be the rising cost of living forcing us to look to bigger companies which can afford $400,000 & who need the Stanford degree more than experience.
Posted by Jack Crossfire | Apr 04, 2015 @ 12:58 AM | 3,585 Views
Took the path following gear off the truck. It was decided that it was too unstable & too fast for the rate of the machine vision algorithm. The hot weather was making daylight drives rare. Getting the test footage that proved the algorithm required lots of manual steering. A slow machine vision autopilot would need to be nearly perfectly on target from the beginning, to have a chance.

The combination of sonar & compass once again emerges as a leading idea. It needs another microcontroller. The initial design keeps a constant heading with the athlete directly behind. The next design keeps a constant heading with the athlete a fixed distance beside.
Posted by Jack Crossfire | Apr 02, 2015 @ 01:01 AM | 4,075 Views
Playing 4k video in Linux is a big deal. The days of software playback are decidedly over. The XVMC interface was the 1st method of hardware decoding. In 2007, it was replaced by the VAAPI interface in Intel cards & VDPAU interface in NVidia cards. Support varies from card to card.

Integrating hardware decoding in an editing program requires intimately dissecting each codec, replacing the specific functions the card supports with hardware calls. The mane codecs to support would be H.264 & JPEG. It's still in the realm of purpose built demos, nothing that could reach a wide user base.

Suppose you had hardware decoding in an editing program. What would you watch in 4k? The format most often viewed is still 640x360. Only rarely is it ever worth downloading something in 720p. The bandwidth to download 720p is now $110/month & rising daily.

The old timers were on to something when they designed the 1st TV resolution, in the 1930's. Motion blur & compression artifacts make most scenes look like 640x360.

It's a lot different than the serious cinema going days of 1999. Most movies are watched on phone screens, in a window, 15 minutes at a time. No-one shuts down for 2 hours to do nothing in front of a big screen, except for single women. They're always shut down.

4k is useful for archives. Probably in the next 10 years, everything is going to start as 4k. Today's 1920x1440 starting footage is still reduced to 1280x720 to make stabilization...Continue Reading
Posted by Jack Crossfire | Mar 30, 2015 @ 12:52 AM | 3,527 Views
So the very last attempt before going to sleep got GPS to go again. Some
years ago, Google dropped support for the LocationManager & switched to the
FusedLocationApi, which was far more complex. The general idea is in this
incomplete Main class:

public class Main implements 
	public GoogleApiClient mGoogleApiClient;

// start GPS
	void init()
                mGoogleApiClient = new GoogleApiClient.Builder(this)


// get location immediately
	void polling()
				Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);

// manually stop GPS
	void close()

// callbacks from the location API
	public void onConnected(Bundle connectionHint) {
// Only getting 1hz
        final int locationInterval = 1000;

        LocationRequest mLocationRequest=new LocationRequest();


	public void onGpsStatusChanged(int event) {

// callback when location is ready.  This is more efficient than polling, but 
// doesn't happen at a known time
	public void onLocationChanged(Location location) {

Another step backward & another step forward. If anyone can make a serial
port require 2 API's & 10 million lines of code, it's the Goog.
Posted by Jack Crossfire | Mar 28, 2015 @ 11:45 PM | 3,569 Views
After several uneventful years, Android GPS stopped working again. The problem initially appeared to be a failure of the app to stay on when the phone was blank. Then it was narrowed down to the GPS module shutting down when the phone was blank. It was further narrowed down to not involving the SDK, IDE, or any settings.

It was further narrowed down to the module not shutting down but entering a mode where it continued reporting locations, but much less accurately when the screen was blank. Each location was very close to the final real location, but slightly moved towards the current location.

The issue 1st appeared after running 13 miles with it. After leaving a Target store, it stopped recording the current position when the screen went blank. The issue now appears like 1 of those cases of putting your thumb on a trace to make a circuit work. In this case, the proverbial thumb would be the screen being on.

The timing of it all agrees with yet another salt water intrusion. These phones are now $30, so there wasn't much concern for protecting it. They're cheaper than buying a standalone GPS module. GPS recording still works with the old battery sucking, unreliable bluetooth hack:


There's another matching phone at the day job that no-one uses, but success varies when changing phones with the same plan.

The innards continue on their way down to a single chip on board.

A contact covered in goo being used to enhance connectivity, but no salt. Wiped the goo off, which did nothing. There were many pads for missing components, near all the antennas.

The other side was a bare sheet of nothing.
Posted by Jack Crossfire | Mar 27, 2015 @ 12:00 AM | 3,207 Views
In what has become an annual ritual, Wednesday was pilot suicide day. Now that Egyptian, Malaysian, & German pilots have killed themselves by crashing their planes, the question is who will kill himself next year?

Easy enough to say humans should be taken out of the loop & there shouldn't be a crew of any kind, but it's yet another case of humans now being unfit to do something they did successfully, 50 years ago, like marriage & politics.

Hard to say there are any more people with mental health issues on the street, than 30 years ago. There could be a zombie invasion.
Posted by Jack Crossfire | Mar 19, 2015 @ 11:39 PM | 4,429 Views
Are you finding millenials to speak a completely unintelligible language?

"On CSI: Cyber, Uber Is the Perfect Vehicle for Dad Sadness Murder"
"The Government Is Testing Myriad Invasive Biometric Surveillance Methods"
"Tag Heuer and Intel Are to Challenge the Apple Watch"
"Mall Cops Catfished Black Lives Matter Activists on Facebook"
Posted by Jack Crossfire | Mar 19, 2015 @ 01:14 AM | 3,682 Views

The next generation of travel fan was finished. While many ideas for a shroud emerged, it still ended up the same as last year. The tripod mounting was much smaller than last year. The maximum power was reduced to 1/4, to make it suitable for indoor use.

The best idea for a shroud would not fit in a suitcase, but be suitable near a pool.
Posted by Jack Crossfire | Mar 16, 2015 @ 11:58 PM | 4,330 Views

Motor Noise comparison (0 min 46 sec)

3 ESCs were compared to find the least noise. None were as silent as a household fan, but SimonK at 18khz was the quietest.

After debating the issue all day, decided to go with the original plan of installing SimonK firmware.

An hour of intricate soldering attached a programming header directly to the Atmega8 SCK, MOSI, MISO, RESET. It had the same pinout as the Atmega328. This was a SuperSimple 15-18A from 2007, predating Arduino by many years. Atmel had yet to even label it as an Atmega.

The firmware was on https://github.com/sim-/tgy

Making the particular image required make tp.hex. There was also a tp_8khz.hex target, which generated 8khz PWM. tp.hex generated 18khz PWM. Installation used the Arduino as ISP sketch, using:

/amazon/root/arduino.heroine/hardware/tools/avr/bin/avrdude -C/amazon/root/arduino.heroine/hardware/tools/avr/etc/avrdude.conf -v -patmega8 -cstk500v1 -P/dev/ttyACM0 -b19200 -Uflash:w:tp.hex:i -Ulock:w:0x0F:m

The motor was now quieter than all the others, even at 19V. 19V at minimum throttle previously made the loudest squeel. There was still a slight wine from commutation, but the squeel was gone. It was quieter than the Castle Creation 35, which was rated at 32khz. The Castle still squeeled at 32khz, probably due to a bug.

There was a nugget on http://majek.mamy.to/en/hobbyking-su...monk-firmware/ about the tp.hex image containing a bootloader, but it required some fuse mangling & yet another Arduino sketch.