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Jack Crossfire's Discussions

EasyStar as a pure GPS UAV

Started this discussion. Last reply by Reto Oct 29, 2009. 7 Replies

 

Jack Crossfire's Page

Latest Activity

Jack Crossfire commented on Chris Anderson's blog post Paper-thin Arduino for a DIY blimp
"Why did he lay out the high tech flex PC board, then revert to old fashioned hot glue & balsa?"
20 hours ago
Jack Crossfire commented on Eli Cohen's blog post FDM Ag UAV
"So what's the difference between a UAV for agricultural surveying & a UAV for some other kind of surveying?  3D printing probably would be ideal when combined with laser etching & milling for making molds, but right now all the…"
20 hours ago
Jack Crossfire commented on AKRCGUY's blog post More Amazing Rocket Footage Shot From Multirotor
"Suspect there was no truth to the story that the head of DJI was been taking these & giving the footage to Russian spies."
Monday

Moderator
Morli commented on Jack Crossfire's blog post Lipo teardown
"@ Carl Thanks,  pls do store these little thermites as safely as possibly. I know of case where whole shack was burned down due to these little dirty guys.  I even  bought one of the aftermath bare skeletons later. @ Jack thanks for…"
Sunday
Carl La France commented on Jack Crossfire's blog post Lipo teardown
"Thanks for the "Heads up " Jack Then air is the oxidizer and moisture in the air could trigger a condition of thermal runaway. You mentioned a white powder forming on some of the plates. I thought it might be some form of oxidation , some…"
Sunday
Jack Crossfire commented on Jack Crossfire's blog post Lipo teardown
"The anodes would have reacted with water in the air if it was fully charged.  If it got hot enough, it could have entered thermal runaway.  The odoriferous fluid in the battery seemed to slow down the reaction with air.  They're…"
Sunday
Carl La France commented on Jack Crossfire's blog post Lipo teardown
"@Morli  I like Jack's  "lets tear the sucker down and see what makes it tick approach?" If it was any body but Jack Munroe and Sgt Rick are right it is probably not a good idea to tear them down. We all have lypos we all…"
Sunday

Moderator
Morli commented on Jack Crossfire's blog post Lipo teardown
"Jack Thanks , great info, now why does it puff when they go bad? is due to some gas build up? Some of my unused LiPo started puffing up, I thought they only do when incorrectly  used. Also when some thing goes wrong, why do they burn…"
Saturday
Jack Crossfire commented on Chris Anderson's blog post How we do autopilot vibration-testing at 3DR labs
"Takes a lot of weight to dampen vibration. That's why they only hire PhD's in subwoofers."
Saturday

Moderator
Sgt Ric commented on Jack Crossfire's blog post Lipo teardown
"Monroe is right in his suggestion that this isn't really a safe thing to do everyday."
Saturday
Carl La France commented on Jack Crossfire's blog post Lipo teardown
"Thanks Jack . I had a lypo go bad at 47 hours of use it swelled up I never took it apart to see if a chemical reaction built up a gas inside ? I had another one swell up just from sitting  that was not put in use? Happy Easter you guys!"
Saturday

Moderator
Sgt Ric commented on Jack Crossfire's blog post Lipo teardown
"There's always someone who's willing to check how sharp the dragon's teeth are."
Friday
Monroe Lee King Jr. commented on Jack Crossfire's blog post Lipo teardown
"Thanks Jack now nobody else needs to do this. What's inside a Lipoly? There ya go. Thanks."
Friday
Jack Crossfire posted a blog post

Lipo teardown

Tore down a completely puffed, dead, 0V cell.  It was still air tight. So basically, it's a stack of copper anodes (-) & aluminum cathodes (+) separated by plastic.  They're soaked…See More
Friday
Jack Crossfire commented on Monroe Lee King Jr.'s blog post Using the Stars, Sun the Moon and the Horizon rather than GPS
"Phones were supposed to be able to navigate by the stars & photograph Saturn by now.  Then Steve Jobless died."
Apr 16
Jack Crossfire commented on AKRCGUY's blog post Nice Introduction To The 3D Robotics Staff
"So how is Google's buyout going to be split?"
Apr 16
Jack Crossfire commented on Oliver's blog post Drone flyby reveals ancient village buried in New Mexico
"That's a real FLIR Tau 2 640x512 30fps cam with wide angle lens, not a hacked point & shoot.  It costs mega bucks & isn't exported."
Apr 14
Jack Crossfire commented on Chris Anderson's blog post Google buys Titan Aerospace (solar powered, high-altitude drones)
"Just practicing buyouts before the big one."
Apr 14
Jack Crossfire commented on Chris Anderson's blog post Gumstix releases PX4-compatible Linux flight controller board
"Sort of sad to see another STM32 board come from these guys."
Apr 14

Wiki Ninja
Gary McCray commented on Jack Crossfire's blog post Robot show
"Thank You Jack, Love your perspective as always. We need to Kickstart the $300.00 3 axis FOG. Then we can sell it to Google for umpteen billion."
Apr 9

Profile Information

About Me:
Head of blog rambling.

The 1st 3 years of flying + more off topic posts are on http://www.rcgroups.com/forums/member.php?u=115141

Image processing, robotics, & aeronautics are on http://heroinewarrior.com

Most diy droners are RC modelers who just want to automate their favorite model plane. I came from an image processing, software, & robotics background, not an RC modeling background, so my focus is on flight control, image acquisition, & blogs that no-one reads.
Please tell us a bit about your UAV interest
x
Hometown:
Pleasanton, Calif*

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Jack Crossfire's Blog

Lipo teardown

Posted on April 18, 2014 at 1:51pm 9 Comments

Tore down a completely puffed, dead, 0V cell.  It was still air tight.…
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Robot show

Posted on April 9, 2014 at 8:29pm 1 Comment



It was packed with unemployed, flat broke programmers.  As far as jobs, there was 1 engineering job at NASA which required many more years of college & had a line of guys wanting to get in.  There is far more talent than demand.  Stock & buyout…

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Facebook buys Occulus VR for $2 billion

Posted on March 25, 2014 at 5:12pm 13 Comments



Not quite the $15 billion they spent on Whatsapp last month, but still more than the $1.1 billion they spent on Instagram.  The speculation is for grand universes of virtual reality news feeds, virtual reality sharing of private UAV flights, but…

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XV-11 lidar copter

Posted on March 13, 2014 at 10:00pm 10 Comments









The journey begins with 3 XV-11 lidar…

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Comment Wall (10 comments)

At 6:54am on March 30, 2008, Howard Gordon said…
Interesting reading. I spent some time with your blog at rcgroups, noting in particular your application of artificial neural nets. I may have missed a jump in your progression, but are you still running the lwneuralnet on a gumstix ? Just wondering, as most neural net libraries use floating point, but the gumstix only has fpu emulation, which is not fast.

Reason I ask is that I converted a simple back prop library to integer math and built it into my firmware, but have just started to think about how to incorporate it into actual operation. As you already have real-world experience in integrating back prop functions, I wondered if you wanted to give the code a try (on the ground) to see if the integer approximations are sufficiently accurate. I map 0.0 : 1.0 into 0 : 1024. If interested, code is here. Let me know if you have a chance to experiment - I'd appreciate some feedback.
At 12:26pm on March 30, 2008, Jack Crossfire said…
Converted lwneuralnet to integer a long time ago. It worked for solving the neural network but not for back propagation. Back propagation required more precision & full range beyond 0-1. 2048 lookup table entries was the largest before the cache overflowed.
At 6:58am on November 28, 2008, Constantinescu said…
Please help me to find all details concerning the software and hardware of version 2 implementation on a T-REX450 with a laptop. I intend to reproduce that on my ECO8.Many thanks,Georges
At 12:26am on November 29, 2008, Constantinescu said…
Thanks for your answer. I alreadi recovered the archive. Could you please send me some more detals concerning the hardware(components, electric connections, procedures for preliminar adjustement of parameters, etc); something "pense bete" for a beginer in the field. Yours Georges
At 10:57pm on April 8, 2009, Harry Cheung said…
Yeah, I should have included that. Anyways, I added a link to the ublox module I have, it's this:

http://www.sparkfun.com/commerce/product_info.php?products_id=8889
At 9:32pm on May 25, 2009, Zik said…
Hi Jack - thanks for your comments on picoc. Yes, it's still alpha quality at this stage. I'm still working on it pretty heavily but hope to reach a 1.0 release in the not too distant future.
At 9:38pm on October 17, 2009, Andy Geppert said…
Jack, any chance you're in flying in the bay area Sunday (the 17th)? I'm in the area this weekend and it would be cool to meet you and see your machine fly.
At 3:10pm on December 4, 2009, Sahil Jain said…
so Chris is from Sparkfun? and you're from...?

sorry, for asking these questions. I am trying to design a board that I want to sell in the $80-100 price range. so trying to understand the target costs. any help would be appreciated. Just for fun, not going to make any money on it. Thanks.
At 3:33pm on December 8, 2009, Jack Crossfire said…
Most of the people on diydrones sell products through Sparkfun. The standard arrangement is to add 40% to the price & Sparkfun adds another 40% to the price. It's no secret. A place like Cloudcap adds 1000% to the parts. Personally working in Indian outsourcing where they expect a 12 hour / 6 day commitment & if you're spending evenings selling your own product instead of your boss's, it better produce a 1000% return or you're out. All your time is company time in outsourcing.
At 3:55pm on December 6, 2010, Hamish said…
$5 per gyro axis? what ? where? gimme gimme gimme!

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