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Archive for March, 2009 - Page 2
Posted by Jack Crossfire | Mar 16, 2009 @ 01:54 PM | 2,829 Views
Been thinking about making a fake H1-B. Unlike American citizens, H1-B's can work anywhere & do anything. H1-B's R like MIT degrees. When U want to hire the best, H1-B is a key word. Most resumes get filtered out just by not saying H1-B. H1-B's get pushed to the front of the line because they have a limited time before they get shipped back to India. If U want the best, U have to beat the 3 month auction deadline.

Citizens using fake H1-B's R going to be an epidemic in the future. The heads of all your government agencies R H1-B's & they're going to protect their buddies. There will be raids on rich mansions & aerospace startups to bust illegal American citizens. Americans R going to be rounded up & deported back to the tent cities & bread lines. To get a job, you'll need a DNA test to prove you're not a son of the revolution. Getting caught with a social security card is going to send U to Gitmo.

Yes, Gitmo is going to reopen to house the flood of illegal American citizens.
Posted by Jack Crossfire | Mar 15, 2009 @ 07:12 PM | 2,656 Views
Was shocked to see climb rate lagging altitude change once again. This occasionally happened with GPS in the past. The first uBlox 5 test had equivalent climb rate.


Airborne dynamic models R busted. Been using them because they said "airborne." It's like having diodes which say "diodes" but are really transistors.

The Pro Power once again returned 12 min.

Unfortunately, sonar is dead. USB doesn't work. It gets a descriptor request from the host but the host can't receive the response. Without a bus analyzer, U can't really optimize the reference software as U need to.
Posted by Jack Crossfire | Mar 14, 2009 @ 12:45 AM | 3,322 Views
What happens when your day job is near a hobby shop? U drive down thinking you've got things under control & drive up wondering what happened.

Pro Power, 3 DT700's, & 3 12x6's on a tri rotor is pretty insane power. Turns VicaCopter into a bullet. A few more evolutions like the Pro Power should have us up to ballistic spaceships. U can break props with a slight twitch of collective. Unfortunately, when it dies, it dies hard. 10.4V is dead. Flight time till death was around 12 min.

Finally, GPS heading is probably as good as we can get it. It stays within 45deg of the right heading no matter where it's pointing. When it starts losing position, the movement pulls it back to the right heading, as designed. Facing South is a bit more accurate. Over 5 minutes, when facing South, GPS can actually tune in a more accurate heading than a magnetometer. Facing West & East is down to +/-45 deg.
Posted by Jack Crossfire | Mar 13, 2009 @ 03:47 AM | 2,959 Views
Since GPS heading got ahead of sonar, you're going to be reading about sonar 4 a while. The circuit which blew up 3 years ago is going to do 1,200,000 bits/sec of sonar capture. This time, U know it needs a 4700uF capacitor. Unfortunately, it still requires an external power supply. Fortunately, unlike your last USB operation, this is a simple client.

USB is much easier to connect than RS232 & if U use the bloated reference software, about as hard to get working as RS232.
Posted by Jack Crossfire | Mar 12, 2009 @ 02:22 AM | 3,202 Views
Another commute & she hovered without a compass again. The algorithm is showing signs of life. High rudder gain & no turns seem to help. U can't get a cold heading from attitude & velocity. U need to hedge the heading with a priori information from the yaw gyro. There's a lot of position oscillation & drift 2 B sure.

So much for that. Now let's go to usaspending.gov & see who's in the money.

Lite Machines (2008): $2,497,182

Don't count on the Coronas coming back.

Procerus (2008): $828,025

Flying wings aren't as in demand as flying suppositories.

MLB Company (2004): $263,676

The more expensive the rent, the smaller the contract.

Adaptive Flight (2008): $50,001

Time to give up on the T-Rexes & upgrade to tri rotors.

Jack Crossfire: zzzzzzzeeeeeeerrrrrrooooooooo

Realistically, usaspending.gov has hardly anything useful. There's nothing on Baldwin Technology.
Posted by Jack Crossfire | Mar 11, 2009 @ 02:23 PM | 3,213 Views
A software comb filter drastically improved the sonar. This gets U in the 6in range at over 14ft. Was hoping to use the laptop microphone in flight test #1 but it sux.

Every commute brings a new pulse, a new indoor test, a new filter. Pink noise is better than constant frequencies. Shorter pulses R better than longer pulses. Multiple nodes R required. Highpass filtering isn't as effective as the comb. Comb filter -> correlation -> integral -> smoothing seems to be the common currency of sonar.

GPS heading got busted in flight #2. Back to Detroit with that disaster. A full IMU & compass is a lot more stable but no fun.
Posted by Jack Crossfire | Mar 10, 2009 @ 03:23 AM | 3,259 Views
The current champion in soundcard sonar is the highpass filter + correlation filter + integral + smoothing. Still pretty awful, but still improving.

Heading without magnetometer is the holy grail. U can't sell a product using magnetometers because they're prone to misalignment if stored near any metal objects or high current.

The main problem is U can't simulate GPS heading corrections. It's never going to be as good as a hand tuned magnetometer. The available movement in a hover is too small to sense very small angles. We're probably 50 years behind China with it.
Posted by Jack Crossfire | Mar 09, 2009 @ 01:33 PM | 2,853 Views
The DT700 12x6's suck 20% of your flight time just like the 2410-9 12x6's. At least Vika 1 is now completely silent & has a lot more power.

The best audible sonar has been the traditional short sine wave pulses. The correlation filter & amplitude sensing take turns with better results. There is no escape. You're going to die from audio torture.
Posted by Jack Crossfire | Mar 08, 2009 @ 11:18 PM | 2,961 Views
Correlation filtering is pretty bad. It's not much better than straight amplitude. It doesn't reject noise well enough to have a constant jet engine sound. U get better results with short bursts of high frequency pink noise. With this grotesque soundcard sonar test, we're looking at maybe 1m of accuracy.

Propeller lightning round

APC 12x6's on DT700's R hopeless. They make a good shake table. The SF 11x4.7's work. 4mm drilled SF 12x6's work & look better.
Posted by Jack Crossfire | Mar 08, 2009 @ 04:31 AM | 3,111 Views
Swapping an 18A Suppo for a 30A Suppo made no difference. It's down to the motors & vibration. We're leaning pretty hard towards running the 2410-9's on 30A ESC's & getting rid of the DT700's.

Only got the DT700's because Chinese shipping is outrageous. The Goog is displeased with DT700 vibration & weight. It doesn't see anyone sticking with them after a few blog posts. The 4mm shafts R a real problem since most parts R for 3mm shafts & no local parts have 3mm shafts. Once U drill out 4mm holes, you're stuck with a vibration machine.

Well, got a sonar ping which U humans can stand. We have uploaded a recording from the electret microphone preamp 4 U sonar freaks. It now completely depends on implementing a suitable correlation filter.

Sonar & U (0 min 20 sec)

Posted by Jack Crossfire | Mar 07, 2009 @ 05:14 AM | 3,213 Views
High dielectric under the pins got us to receiving on the airframe, but running the PIC at 25Mhz jammed it completely. Running the PIC at 40Mhz was crummy but it worked slightly. Alternative power supply? Fuggedaboutit. It's RF from the PIC.

While ghetto rotor chews on her crummy GPS, it's time for another propeller mount on Vika 1. The propeller mount worked but attitude control was gone. It's oscillation + constant control losses. The 30A Suppo's R the main suspect followed by vibration.

Well, the mane problem with sonar is we don't see a way to pull it off for less money than GPS. U can build GPS modules that weigh less than sonar. With GPS, U can skip the ground station completely & use 802.11 instead of XBee's. With sonar, U need a ground station.

Not sure exactly how audible sonar would work. U need a true USB microprocessor to move the audio fast enough. U need a super steep bandpass filter with under 0.1s phase shift. Then, U need to adjust hardware gain from software.

Another idea is to synthesize the known soundwave on the ground station & correlate it with the received sound wave to get the phase.
Posted by Jack Crossfire | Mar 06, 2009 @ 02:22 PM | 3,273 Views
Ghetto GPS didn't work on the airframe. Never got a thing in the field, with all other systems disabled, at 100ft AGL, or any of that other stuff. The latest theory is foam touching our beloved upside down pins.

No problem flying ghetto rotor manually, using IDG300's. Just barely enough power to go up, even with the new motor mounts. Slightly tail heavy according to the PWM recording. Ghetto LEDs were probably visible enough.

Now lets get one thing perfectly clear, for everything U know & everything U've done, there are millions of people who know & do the same thing. In a planet of 7 billion people, it can't not happen. They don't all show it on the internet. Even fewer get on The Goog.

There are millions of people with the skills to put VicaCopters together, millions of UAV's of 1 kind or another in the world, & thousands of autonomous tri rotors. There are more UAV's than all the full time soldiers in the world. A world war fought purely by the current UAV fleet would be broader than anything humans could pull off.

1 autonomous tri rotor is produced somewhere in the world by 1 Jack Crossfire every day. All the defense contractors & hobbyists of the world produce at least 1 UAV every second.

Compared to the human birth rate of 2.5/second, humans have probably 2 years before their birthrate is outstripped by UAV's. In 30 years, humans can expect to be outnumbered in total number by UAV's.
Posted by Jack Crossfire | Mar 05, 2009 @ 04:19 AM | 3,285 Views
Got a sheet of copper in the mail last year but only figured out a use 4 it recently. It's now the ground plane of our uBlox 4 ghetto GPS module. The tri rotors don't have enough flight time to lift the Altoids, so it was time to give passive antennas another try.

The passive antenna mounted right above the module actually worked when connected directly to a PC. Now that old uBlox4 was a better investment than AIG.

Does ghetto blox receive anything fully integrated on the airframe? Fuggedaboutit. We have a few more commutes to go with this one.
Posted by Jack Crossfire | Mar 04, 2009 @ 06:12 PM | 3,027 Views
For all your heroine worshipping, it's time U faced facts. Heroines caused great depression II.

In the old days, the media called heroines investing geniuses because they were experts in housing, the CEO of the house. They knew all the housing & domestication stocks & those stocks were doing great. Their stereotypical credit card charging made them richer through the power of housing inflation.

Where are the CNN stories praising heroines for their domesticated genius now? When the unlimited credit disappeared, the CEO of the house was yet another bimbo with a stack of credit cards.

CEO of the house before. Now CEO of the depression. The mortgage bailouts are bailouts for heroines.

Men wanted gadgets. Heroines wanted real estate. How many of your heroine coworkers bragged about how they made their husbands buy a house instead of a model copter back in 2005? The depreciation on average Bakersfield mansions would cover 300 model copters, if taxpayers weren't covering it.

The fact is if heroines thought more like men & wanted gadgets instead of kitchen remodelling, Micron wouldn't have laid off all of Idaho. We'd probably have humans exploring Mars instead of plunging their total economic output into mortgage bailouts.

Heroines caused great depression II (0 min 40 sec)

Posted by Jack Crossfire | Mar 04, 2009 @ 02:02 PM | 3,226 Views
The DT700's R real bricks. Don't be surprised if these bricks don't fly for very long on the current batteries. The battery budget of course went to higher income tax so U could get more equity out of your tree houses, but don't bother selling those tree houses to US. We're sucked dry by higher taxes....Continue Reading
Posted by Jack Crossfire | Mar 03, 2009 @ 03:10 PM | 3,141 Views
There it is. Vika II. She does indeed fly. Can only go 1ft off the dumpy apartment floor until we get a break in the weather. That's not predicted for yet another week. Meanwhile, it's full speed ahead between commutes on upgrading Vika I's propulsion, installing Vika II's GPS, implementing GPS -> heading corrections....Continue Reading
Posted by Jack Crossfire | Mar 02, 2009 @ 01:48 PM | 3,974 Views
No-one is doing PC soundcard sonar, but we feel it's the next step 4 U. There's no way analog circuits & microprocessors R going to do the job. We don't know enough about the ambient noise in audible frequencies to filter it. Some quality time with a PC soundcard can show U exactly what can be extracted from audible noise & how to extract it before investing any more in sonar.

Still think 3D sonar is going to be a good tool because humans have been doing it for years. Humans can filter out ambient noise & localize objects in 3 dimensions. 3 humans could probably fly a copter blindfolded if U got each human aligned in 1 axis. Maybe we should get some Slave 1-B's from India instead of sonar transducers.
Posted by Jack Crossfire | Mar 02, 2009 @ 03:18 AM | 3,106 Views
DVD+R DL doesn't work & it's slightly more expensive than hard drives if it works. You're lucky to get 2 good disks in a pack of 25. A blu-ray burner would be $200. 1TB of Blu-ray media alone is another $200. This is yet another Sony fanboy product. Sony turns $400 into $200.

Also, optical storage is inefficient. You can never divide files up exactly into 25GB disks. Back in the old days, we used to divide files into exact 1.44MB floppies using the dd command. Then we would spend 10 minutes walking a box of floppies from Heritage to Crabtree to transfer a sound file. Nowadays, we need to free up 10 hours a week for commuting in a car to pay for an internet connection. Progress.

Optical drives wear out rapidly. Once U commit to optical storage, U forever have to buy new drives. We average 1 drive burnout every year.

What about the perpetual need for optical drives to watch movies? P2P is the most efficient way to watch movies. You can't win against progress, no matter how tough you are, how high you raise taxes, how many people you enslave, or how large your market cap is. P2P is the way it's going to be done.

The only conceivable reason for optical storage is to avoid depreciation. The depreciation on hard drives costs you. You have to throw down $200 to get 2TB, but you won't use the last of it until it's $20. You can buy DVD's in increments. By the time you reach 1TB, you pay the current price for those last bytes instead of what they cost initially.

heroine2200 long version (3 min 31 sec)

Not sure what to do with Heroine 2200. Spent 3 years building DVD robots of one kind or another because a robot that organises disks seemed perpetually valuable & she never forgets. She could be modified to organise any slotted medium. Most likely, 20GB flash drives will become $5 & she'll end up organising hundreds of flash drives.

There is a chance of getting rid of her loading tower & just having 2 storage towers.
Posted by Jack Crossfire | Mar 01, 2009 @ 12:38 AM | 4,225 Views
4 a good time, go to


Sonar transducers were $1.50 back then.

He could afford dozens of transducers to make it omnidirectional. He didn't have to copy a Maxbotix reference design. He used straight amplifiers & manual gain.

That inspired us & sure enough allelectronics.com has $1 transducers. No more Maxbotix for transducers.

A bit more playing with audible sonar pings & clearly it's a disaster. It's so sensitive to ambient noise, there's no way it would work with noisy fans.

Nothing left but to finish ghetto rotor using GPS.