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Archive for January, 2015
Posted by Jack Crossfire | Jan 20, 2015 @ 11:15 PM | 5,845 Views





It's amazing all those formerly penny chinese businesses of taxi cabs, pet furniture, LED blinkers, & bike delivery are now multi billion dollar Google acquisitions. Unlike 1999, there are no IPO's. All the money is in buyouts paid to the founders. It takes a lot less people to do what took a staff, 15 years ago. There are no more tales of Netscape staff members retiring. No more tales of six figure secretaries. There are no more secretaries or IT staff. The whole show is just a CEO & an iPhone.
Posted by Jack Crossfire | Jan 18, 2015 @ 09:27 PM | 5,970 Views


The long time quest for a KH-11 model ended when I remembered paper hubble models abounded. The KH-11 was once believed to be a short hubble with no instrument package. A later Kiwipedia update showed it being identical to hubble & having a large propellant tank for reboosts.



Decided to stick with the earlier theory. No matter what it really is, it's still vastly different than hubble.

The paper model wasn't as inspiring as hoped. It had to be 2.66x smaller than the NASA model to fit in the levitator. The toner fell off. The model was intended for a color printer. Left out the high gain antennas because they wouldn't fit in the levitator. Left out the instrument boxes because they would be crushed by the magnet & were microscopic.


...Continue Reading
Posted by Jack Crossfire | Jan 18, 2015 @ 02:50 AM | 6,271 Views
BART has constant, massive delays. What is a 45 minute ride on paper is normally 1 hour. The delays are 1/4 caused by equipment failures & 3/4 caused by people. There is a big difference between the news & how happy people actually are, because they're obviously not getting by while the news would have you believe things suddenly got rosy on Jan 21, 2009. The reality is there are so many protests, crime, & health problems among people who are doing a lot worse than 6 years ago that nothing is working.

Living on a train for 10 hours/week is more productive than operating the break pedal in a car, but it doesn't leave any time to do anything but what can be done on a laptop. The sum total of a week of physical fabrication amounts to a very minimal revision of the Tamiya circuit board




The new board probably ended up being unnecessary, since it ended up manely removing most of the reworks instead of integrating them.

Current sensing - a decided failure. It was easier to set a constant RPM than try to adapt the RPM based on power. Couldn't get an accurate reading of current usage. The user can manually adjust RPM based on steepness.

Headlight MOSFET - not worth the extra board space. Only set once per drive. Required a gyro recalibration.

3.3V - needed connections for external regulator.

Servo - needed connections for external regulator.

ESC - Needed PWM signal on 5V pin with pad to jump to 5V. The pad didn't make it.

Gyro -...Continue Reading
Posted by Jack Crossfire | Jan 13, 2015 @ 12:09 AM | 5,991 Views




The journey begins with grinding this thing down.


Then comes standing off the screw holes with spare plastic parts & laminated 1/16" plywood.

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Posted by Jack Crossfire | Jan 11, 2015 @ 01:16 AM | 5,903 Views




Does this $216,000,000,000 turd ever load?
Posted by Jack Crossfire | Jan 09, 2015 @ 11:58 PM | 5,912 Views





As bad as the quality is, compared to what you can download from Australia, there's nothing like seeing it as it appeared over your home.
Posted by Jack Crossfire | Jan 07, 2015 @ 10:53 PM | 5,741 Views
Last year, a car which followed the athlete instead of the path began to emerge as the best solution, but a car in front doesn't know where you're heading, only which way to turn to keep you in frame. This causes it to drive in circles.

Setting the car to follow a desired magnetic heading won't work on its own, because the magnetic heading isn't precise enough. The latest theory is if the car senses both a desired magnetic heading & the direction towards the human, it can stay on the path. This works only if the human is directly behind the car, with decreasing accuracy as the human moves alongside the car.

The car maneuvers so the angle from the human to the car to the desired magnetic heading is 180. The desired magnetic heading is changed from the stick controller to steer the car.

If the desired magnetic heading is off, following it leads the car off the path, but the human stays on the path. As the car heads off the path, the human-car-magnetic heading shrinks & the car turns back towards the path to make it approach 180 again. Wherever the human goes on the path, the car maneuvers to stay in front.




The 2nd case is the human alongside the car. This requires a different algorithm that maintains a fixed distance to the human. If the human gets farther away, the car steers to reduce the distance. This would be much less accurate than following behind the car.

The 3rd case is the human in front of the car. It just needs the...Continue Reading
Posted by Jack Crossfire | Jan 04, 2015 @ 07:43 PM | 5,225 Views

Drove another 8.5 miles with the forward looking webcam. This would be the actual video technology in a path following solution. Had both batteries onboard. The old battery only went 3 miles & the new battery had more than 5.5 miles. Time to send Hobbyking another cash infusion. Also suspect 10min/mile is much less efficient for the current gearing.

Tried driving off a curb, but flipped, snapped off the wide angle lens, & this made the pi crash. Fortunately, it got 8 miles of footage. Forward looking video had much higher compression.

Edge detection showed promise, with gopro footage. Helas, JPEG compression erased too much detail & created too many macroblock lines. Would need to try again with the webcam in uncompressed mode. The wide angle lens was a waste of time for forward vision & created too many reflections.



Original image

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Posted by Jack Crossfire | Jan 04, 2015 @ 01:17 AM | 6,016 Views


It was time to gather some test footage for a vision based path following algorithm. The only way was a complete setup with the actual camera in the actual position.


Glued a wide angle lens on it & mounted it to get the widest possible field of view.


...Continue Reading