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Posted by Jack Crossfire | Jan 20, 2014 @ 08:00 PM | 2,185 Views

A complete home entertainment system for FPV, but with the same old analog NTSC video.

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Posted by Jack Crossfire | Jan 17, 2014 @ 03:30 PM | 2,396 Views
The phone started dying after only 6 months. The back & menu buttons died. Then the bottom of the touch screen died. Suspected salt invasion from days of running.

The phone was indeed invaded by salt.

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Posted by Jack Crossfire | Jan 16, 2014 @ 10:12 PM | 2,432 Views
So the pondering about cubesats was lame, but now there is a new idea. Get a cubesat to photograph a spy satellite up close. It can't be very far from happening.

The mane spy satellite of interest is USA 224. It's in a sun synchronous polar orbit that passes over Baghdad at noon. It's low enough for a cubesat to reach. It can only be seen from the ground in Australia. It is believed to be a shortened hubble space telescope which can be approximated by chopping off hubble's instrument section.

Another spy satellite worth visiting is USA-223, the largest satellite in orbit.

It has a 100m dish. It's in a geosynchronous orbit over the middle east. A cubesat would have a hard time reaching that orbit.
Posted by Jack Crossfire | Jan 16, 2014 @ 01:16 AM | 2,354 Views
Was hoping Elysium would have some stunning visuals of a space colony, but all you get are 2 hours of Matt Damon bleeding & some lame immigration policy narration. Finally figured out why everyone suddenly got obsessed with immigration policy in 2013, manely the lack of healthcare entitlements to illegal immigrants.

As one who hasn't had any health insurance since 2009 & has only seen people leaving US to obtain healthcare overseas, this story never made any sense, but it is what the media tells us to think. These movies also forget that once the immigrants own all the stuff in Elysium, what do they do about all the citizens who now want their stuff?

The conversion of Jodie Foster & William Fichtner from unemployed astronomers to most evil pair in the universe is complete. Never seen so much evil.

For all the accusations between republicans & democrats, the immigration policy debate is more of a class war than a party debate. The richest 1% want cheaper labor. The poorest 1% want entitlements. The middle class wants to keep their jobs.

The leaders of the system want expanded immigration while the workers under the system want less immigration. The government & the people are at odds, as every attempt at government has been.

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Posted by Jack Crossfire | Jan 14, 2014 @ 07:48 PM | 2,430 Views
Whether to port bits of Arducopter to Marcy 2 or port bits of Marcy 2 to Arducopter has been the mane question. Arducopter is a very large & growing nest of features, with a lot of hype around a few features that might be useful. Porting bits of Arducopter to Marcy 2 has been the only thing that fits into the 2-4 weeks between all up demos.

The additions or at least the hype is getting more frequent, as 3D Robotics has more money to invest in features, but the hardware has remaned the same. Recently, the big ones have been autotune, hybrid mode, inertial navigation, & Kalman filtering.

As with everything nowadays, the marketing for every new feature is in your face & viral, while reality sometimes differs. Actually having a stock arducopter to test with optimal parts is financially prohibitive. $800 + stock RC system + crash repairs is quite a lot by Chinese standards.

The inertial navigation still seems a bit like smoke & mirrors. There hasn't been a side by side test of inertial navigation vs. GPS only. The question is how much new information they can actually get from the same old garbage input.

The autotune feature is potentially useful, conceptually simple, but very time consuming to perfect. It's in 1 small file called auto_tune.pde. It commands a bunch of rolls & pitches to optimize an existing set of tuned attitude hold gains. It doesn't touch heading or position.

Once again, there's no obvious improvement that jumps out....Continue Reading
Posted by Jack Crossfire | Jan 14, 2014 @ 12:51 AM | 2,698 Views
It was decided that the $40 RC car was good enough to justify modifying it as an exercise tool. The mane task is converting the steering to a servo.

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Posted by Jack Crossfire | Jan 09, 2014 @ 10:36 PM | 2,971 Views
7 mile RC car drive (3 min 26 sec)

The gopro died after 6 miles & the car died after 7 miles on a 1.5Ah battery. Its speed was 9m30s/mile until the battery died.

Mounted the camera backwards for the next one.

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Posted by Jack Crossfire | Jan 08, 2014 @ 07:10 PM | 2,382 Views
Ran with the RC car being manually controlled. Keeping it on the narrow urban sidewalks was impossible. After leaving the urban jungle of Rain Ramon, it could start staying on the 15 ft wide trail. After several miles, banging out a straight line became automatic. Its tiny wheels made it erratic on the crumbling parts of the trail. 1 handed driving is still difficult, but better. The controller needs to get smaller.

The gopro naturally died after 6 miles. The RC car went 7 miles on 1.5Ah, then suddenly died & had to be carried 6 miles home. That was way beyond expectations. Thought it would go 1 mile. 6 miles on 1.5Ah should be considered the range. It has a brown out shutoff. A brushless motor should get it up to 9 miles. Its nominal pace was 9m30s.

This system is fast enough to be a pace maker for the slow, long run, but needs more NiMH batteries which are super expensive compared to Lipo. Would only invest further development in a high end brushless system. Those things are expensive, even from Hobbyking. They're $75 - $100 just for the frame.

Don't think the changes are substantial enough to sell a manually controlled, modified RC car as a workout coach. The only differences are the 1 handed control, longer range, & attachments for water.

Making it completely autonomous is pie in the sky, but there might be a way to get it to drive the straight sections or avoid obstacles. A camera which automatically tracks the runner would be something. There's absolutely nothing which can make a timelapse video of an athlete during an entire run, but it can't be far off.


Interesting to note how the speed followed the NiMH discharge curve for 7 miles.

Lion after 6 miles. There's no way to see yourself this far from home besides robot.
Posted by Jack Crossfire | Jan 08, 2014 @ 01:50 AM | 4,032 Views

RC Car Run (2 min 56 sec)

A better battery, proportional steering, variable throttle, autonomous athlete following, & it could be a useful exercise tool. The reality of crossing streets & staying on the path makes the autonomous following hard, but the rise self driving cars gives hope.

It's really crusty. The steering is binary. The speed is binary. Instead of a steering servo, it bangs a motor completely left or right to the stalling point. It can't go backwards.

For someone who never had an RC car before, the amount of mechanics required to perform steering & optimally transfer power to the road is quite amazing. 4 wheeled vehicles are pretty complex & there's no simpler way of doing it.

The 2 wheeled balancing robot eliminates a lot of the complexity, but it still can't achieve the ultimate fluidity in turning that fully articulated front wheels do.

A manually controlled vehicle might be viable for exercise. A vehicle which carried supplies for 30 miles has been on the radar for a while. The quest began to make single handed driving more ergonomical.

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Posted by Jack Crossfire | Jan 06, 2014 @ 02:24 AM | 2,601 Views

Everyone wants to hack a laser tape measure for aircraft navigation. It would indeed make a cheap, extremely accurate, reliable altimeter.

Today, it's the DLR130. It outputs at 1cm accuracy at 3Hz. You need 10Hz for flight, so maybe there's a way to speed it up.

It's very well constructed.

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Posted by Jack Crossfire | Jan 04, 2014 @ 04:10 AM | 2,405 Views


It's not necessarily quad copter, but tractor based. Did not know Calif*'s mane crop was lettuce or that it produced any vegetables at all, since there hasn't been any rain since 2012. Though quad copters harvesting lettuce is a highly dubious proposition, there's certainly money to be made from tractors.

That guy was rich. Listening to him complain about the lack of PhD's from Stanford to design computer vision algorithms, you thought just stop being a dick & hire people who know how to design computer vision algorithms instead of insisting they have a PhD from Berkeley. Most of the discovering, inventing, engineering, living & dying in this town is done by makers & hackers working in garages. Yet another overstuffed taco salad supported by the federal reserve.

Your other thought was agriculture might actually become a big business as our generation believed 20 years ago. Unlike what we believed, the money is not going to biologists who study genetics, but to designers of robots & businessmen.

There are no jobs for biology majors who learned about robotics on their own, only for engineers who learned about biology on their own or businessmen who can track down farmers with bucks.

It's probably a supply & demand issue. Few people can pull off the engineering side & business side while everyone can do the biology part.

A huge aversion has emerged to the genetic engineering we thought would comprise most of the expansion in food supply. A lot of that is lack of knowledge about genetic engineering & movies, but whatever. For now, you can't use genetic engineering to feed Africa. That leaves using automation to expand the biological system we already have.
Posted by Jack Crossfire | Dec 31, 2013 @ 05:08 AM | 2,480 Views


The sight of the 6th Street bridge in a music video made it unbearable to not do some running. It's the bridge of despair & the bridge of memories.

There was great despair to cross paths with the Jesus Heroine twice on it, a tiny fraction of a half marathon apart. There was being eyeballed with great intensity on it & longing to be in that parallel race just a few hundred feet ahead. These memories will soon recall a much younger & distant age.

In 2015, it's going to be torn down & replaced by a seismically more robust & hideously ugly piece of warped steel. The asphalt where me & Jesus Heroine ran will be no more. The backdrop seen on those days will never be reproducible again. There will be no trace of what was.

So many other men have memories of that bridge, there's a website about it. http://www.the6thstreetbridge.com/ It's getting more & more common with increasing age, for our past to be erased as structures from our past wear out, become economically unfeasible, & get destroyed.
Posted by Jack Crossfire | Dec 30, 2013 @ 05:37 PM | 2,423 Views

Clicking through some ads reveals there's now a flood of banging good GPS autopilots out there, being marketed towards RC pilots. They're a lot more stable than anything I could afford, owing to the latest GPS module, barometers, & the arducopter source code, which they all undoubtedly copy.


Gone are the days when someone would tear them open & study the part numbers. The new customers are RC pilots with no idea what's inside. It wouldn't be surprising to find uBlox-7 & MS5611 in all of them.


Even the mighty Horizon Hobby finally caved in & started selling a GPS autopilot, though marketing it exclusively as a return to home feature.

The trick with autopilots is once you have one, now what? They're good at making timelapse movies. They can fly to places that were impossible for a human to reach manually, but the newest FPV systems make those places accessible for a human.

They're supposed to be good at returning to home when contact is lost, but there's very little evidence of that being used. It's still a lot of trouble to wait for GPS to lock on, make sure everything is calibrated correctly, just for that 1 feature.

There was some energy behind the following camera concept, but they probably weren't accurate enough to do a good job. Now there's hope for massive agricultural demand.

Autopilot for an RC pilot can get pretty boring, once the novelty of seeing it hover wears off. Hobbyists who design robot algorithms still seem to be the mane customers.

It was suprising that the mane media avenues: tested, flite test, rcmodelreviews were completely devoid of the GPS autopilot boom, emphasizing indoor quads instead. Even the mighty black sheep became famous not because of an autopilot but manual control.
Posted by Jack Crossfire | Dec 29, 2013 @ 10:43 PM | 2,436 Views
After 2 days of tracking down dependencies, fixing compiler errors, figuring out the nest of incompatible w objects in boost, mupen64plus finally ran the Robotech ROM image. Figured it would be an interesting study of what being 1 month from completion really means.

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Posted by Jack Crossfire | Dec 29, 2013 @ 03:59 AM | 2,617 Views

There are some poor quality videos of Robotech Crystal Dreams, a failed game from the 1990's. For all the fans gloating over it, it looks pretty bad.

There were a lot of grand ideas for what it was going to be. What kids actually recovered from the demo appeared to be a very simple flight simulator with a small number of models from the Robotech universe, too small to actually see anything.

Like a lot of 1990's software, it was a big idea with only a tiny amount ever getting finished. Modern frameworks may be a lot slower, but are high level enough that programs get a lot farther than they used to.

Robotech crystal dreams (5 min 24 sec)

The developer of the game managed to create some demo footage of some hidden levels & levels the fans never got to. Most of the footage is character animation for unfinished sections.

It looks like a simple flight simulator with some models from the Robotech universe. They also had some elements of Japanese animation. Besides visuals, it's hard to differentiate a game as a Robotech game. The objective must always be shooting & flying.

There is a Robotech DVD somewhere with more demo footage. While all of you were getting married, I spent my 20's buying the 1st Robotech DVD set, which sadly was not the one containing the demo footage. There were at least 3 sets in total.
Posted by Jack Crossfire | Dec 28, 2013 @ 05:29 AM | 2,388 Views
Marcy 1 outrunner flying (8 min 51 sec)

The outrunner with L bracket & slight thrust vectoring increased flight time from 9 minutes to 14 minutes. Can't think of any other vehicle which can hover for 14 minutes on a 450mAh 7.4V. In addition to the flight time, it's very quiet & hypnotic.
Posted by Jack Crossfire | Dec 27, 2013 @ 01:06 AM | 3,149 Views
So like a brushless gimbal motor, a brushless inrunner relies on higher torque to hit lower RPM. That requires a higher turn count. The lowest RPM 12mm inrunner of today uses 20 turns to hit 3800kV. The 3600kV Feigao would have had more turns, making it very expensive. It's now a true collector's item.

The lowest RPM 12mm inrunner still being mass produced is the mightyBA BL1230 4200kv 20 turns.

Flexing of the wing had no effect. The vectored thrust was the next suspect. Unbent the spruce. Ate the weight penalty of an L bracket. Higher coning angle had long been observed to be more stable.

Eliminating the vectored thrust did indeed make it stable but take more energy. It still weighed much less than the inrunner. Adding vectored thrust made it less stable, but take less energy.

There is a sweet spot between efficiency & stability. A maximum functioning angle seems to be 15'. 30' is unflyable. It can be gained by either bending spruce or making a different L bracket. A variable angle bracket would be ideal. There's also adding washers under the motor to tilt it.

A plastic variable angle L bracket could be made with 2 sliding pieces hot glued together & a hinge. Heat it up to adjust it.

The L bracket was dreaded for years, but physics won out, in the end. There was no way to make an elegant bent spruce piece.
Posted by Jack Crossfire | Dec 25, 2013 @ 02:55 AM | 2,654 Views
So every system on Marcy 1 died simultaneously. There was nothing unusual about the circumstances. It was another crash. There was no power cycling.

A very brief, transient high voltage appeared on the 3.3V bus. The transient was caused by probing the I2C bus with a voltmeter & contacting a high voltage solder ball. It's one of those split second events you never actually remember but know happened from doing it hundreds of times before. The PIC survived because it has an internal voltage regulator.

I2C stopped working when a reset routine was added to handle a dead radio. The reset routine on the PIC doesn't reset the I2C driver or peripherals. Most often, they would go into an unknown state & die. There wasn't a problem resetting when a software I2C driver was used, leading to the hardware I2C driver & not the peripheral as the problem.

Like most microcontrollers, the PIC doesn't receive any more UART data if the receive buffer is allowed to overflow. It has to initialize the UART interrupt without delay, on startup. If a character got in before the initialization, it would need a reset to recover the UART. That leaves starting up without I2C, resetting to get the radio to receive something before starting the I2C peripherals.

Adding ballast to the balance beam didn't make it more stable. There's another idea & a theory that having a highly flexible wing is making it more stable. Marcy 1 is a very unusual combination of aerodynamics.
Posted by Jack Crossfire | Dec 23, 2013 @ 08:38 PM | 2,819 Views

In the beginning, there was spyplanes.com. Then there was 3drobotics.com. What a surprise when my recuiter spam feed came up with another one in San Francisco called Airware. They showed a location in Newport Beach, but like so many others, probably had to expand North to save on real estate costs & be closer to the cloud/dot com boom.

It's yet another agriculture quad copter play. Besides tacitly luring photography hobbyists by branding the quad copter as a professional product for agriculture, there's no logic behind all these startups pitching quad copters for agriculture. They can't efficiently image thousands of acres. Sensefly probably had the best model with flying wings, but not the money or the resources to build up a community movement.

Despite not getting any interest, I did manage to get the recruiter to return a phone call, a huge breakthrough. The UAV business has just exploded to the point of not being the domain of makers & self starters anymore. They just want formal masters degrees.
Did the maker movement make the engineering degree mandatory?

In the old days, there was a novelty to someone picking up electronics on his own. It showed the ability to learn without being told what to do & the ability to be motivated without the threat of failing a class. While there were always places like Lockheed which would never touch someone without a formal engineering degree, it...Continue Reading
Posted by Jack Crossfire | Dec 23, 2013 @ 06:56 AM | 2,820 Views

A long coveted spruce bending jig begins operation.

It seemed to achieve the desired bend, but it took a whole day to soak & bend the wood. Bent it to 66' expecting it to settle at 45'. It won't retain its shape in wet weather.

While browsing Kickstarter projects, it became clear that most of them were selling self built kits to get a high volume low price. It would require some massive laser cutting. Preparing instructions & replacing all the parts users screw up would be a bitch.

Every day, there is a new idea, a new price point to calculate, a new design change, so it never is finished.