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Jack Crossfire's discussions

Helicopter UAV based on a Raptor 30

Added a reply Jun 5

FAA - Petition for Rule Making

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Jack Crossfire commented on the blog post Stanford quadcopters rock! Jul 4

Jack Crossfire commented on the blog post Stanford quadcopters rock! Jul 3

Jack Crossfire added a video: Little Miss Moffet

Jul 3

Jack Crossfire commented on the blog post Arduino GPS shield with SD card logging. Jul 1

Jack Crossfire commented on the blog post Diy Drones at Maker Faire! (on popsci.com) Jun 30

Jack Crossfire replied to the discussion Manual Control Problems Jun 28

Jack Crossfire commented on the blog post CropCam user pushes for FAA exemptions Jun 27

Jack Crossfire commented on the blog post Microsoft Virtual Earth now accepting DIY aerial imagery Jun 25

Jack Crossfire commented on the blog post Microsoft Virtual Earth now accepting DIY aerial imagery Jun 24

Jack Crossfire commented on the blog post Is GPS good enough for altitude hold? Jun 24

Jack Crossfire commented on the blog post Is GPS good enough for altitude hold? Jun 23

Jack Crossfire commented on the blog post UAVs for profit.......or development Jun 22

Jack Crossfire commented on the blog post Review: new Arduino Nano board Jun 22

Jack Crossfire added the blog post 'XBee price increase' Jun 22

Jack Crossfire and Chris Anderson commented on the photo How to connect a Blox Jun 21

Jack Crossfire added 2 photos. View Photos

Jun 21

Jack Crossfire commented on the blog post How can we make IR beacons with unique IDs for Blimpduino? Jun 21

Jack Crossfire and Sgt Ric commented on the video hard day at the office Jun 18

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Jack Crossfire's Videos

Little Miss Moffet Added by Jack Crossfire
Neural network's last stand Added by Jack Crossfire

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Jack Crossfire's Blog

XBee Pros have been raised from $32 to $36. Feel like a fool for not buying more at $32, although the direct store still has some. Still have 2 $32 modules from last year. The higher priced model is the XBee ZB ZigBee PRO Series 2 supporting "more dense mesh networks". Maybe it even has Techron to clean your speed controller. In 5 years these obsolete modules will be $65. Should buy some paperclips. The next bull market is paperclips I tell U. The good news is a new 900Mhz module has appeared… Continue

Posted on June 21st, 2008 at 5:55pm — 1 Comment (Add)

uBlox5 the enabling technology

uBlox 5 is an enabling technology as far as navigation is concerned. We're going to see amazing things in cheap autonomous rotorcraft because of it. Optical flow may actually be knocked out by uBlox5 & the former complexity required to damp velocities is gone. Have 2 videos of the uBlox 5 controlling position in the wind. This is of course, totally electronic stabilization without flybar.

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Posted on June 1st, 2008 at 1:30am — 3 Comments (Add)

Rotorcraft endurance records 4 U

Another first from the "don't apply if your resume doesn't say MIT on it" department. The Eurocopter may have been the first to summit Everest, Alan Szebo Sr/Jr may rule the 3D kingdom, but the Hummingbird's got the endurance record now. http://www.darpa.mil/body/news/2008/A160DARPAReleasev4.pdf Now if only the Hummingbird could repeat these stunts without crashing.

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Posted on May 21st, 2008 at 9:00pm — 6 Comments (Add)

UAV #1

This was my first UAV.

It was the simplest, cheapest UAV possible: a magnet. It couldn't fly very high, it couldn't follow waypoints, it couldn't carry much of a payload, it was even more unstable than a helicopter, but it could fly as long as PG&E didn't have a rolling blackou… Continue

Posted on May 13th, 2008 at 10:00am — 1 Comment (Add)

Goo Tube blowup

Blowup of the stationary hover video for the ultimate flying feeling.

Posted on May 9th, 2008 at 3:16pm — No Comments (Add)

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At 12:26pm on March 30th, 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 6:54am on March 30th, 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.