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THIS WEEK IN AEROSPACE

Posted by Jack Crossfire on December 11, 2009 at 10:30am

There it is. The coveted $3.30 14.7456Mhz crystal. With that & a small bugfix installed, the C328 works perfectly at 115200, the pictures stream continuously from the microcontroller & we're up to XBee lockups.Even 1 way communication locks up in this high interference environment because the ACKs collide. Your only option is broadcast mode. With broadcast mode & 3 retries, you now have more errors but the Xbees don't lock up. The command to set the number of retries is ATRR & it's undocumented on the XBee 900.With the 900Mhz & 2.4Ghz running simultaneously we now see the huge difference in range. The 900Mhz dies at 300ft, much closer than the 2.4Ghz. This is with wire antennas. Since 900Mhz has always been more expensive than 2.4Ghz, don't expect to get 2.4Ghz range out of 900Mhz for $42. High gain antennas are required. Dual 2.4Ghz modules don't work well either.So that's $140 for 300ft .2fps 320x240 video. Ended up with this arrangement because 900Mhz was originally supposed to be for telemetry. The C328 was a cheap way to get preview video by recycling the 2.4Ghz radio. It's clearly a disaster compared to what people are doing with a $90 Ativa/Camileo & $80 Range Video radio.http://rcexplorer.se/page14/hdcv/hdcv.htmlvideo.tar.bz2This is the updated source code for the wireless camera system.This is our full motion aerial footage of the Rain Ramon XMas tree. The autopilot was programmed to always point towards the tree, but L1 GPS & GPS derived heading being what it is there was a lot of manual intervention. If the weather wasn't already closed in for the year, we would fly this at 1m/s with manual heading & time lapse it to get more accuracy.Heading from the magnetometers & accelerometers back in the day was never very accurate either. Dynamic acceleration & local induction always made it approximate.& this is a segment from a very old flight showing a fast autonomous descent into downwash using the Marcy Maneuver.MARCY 1 VIDEO NOTESMain ideas for getting video out of Marcy 1 revolve around using 1 raster line of a chip camera like the TCM8230MD, but no data radio has enough bandwidth to do the job. So the best idea is to scan 1 raster line every several revolutions, stick with a photodiode for heading & use the rotation period to figure out where the rasterline was scanned. Accumulate rasterlines from many revolutions to construct an image.The camera would be read on a 2nd CPU. Data would be sent to the main CPU's UART & multiplexed on the main radio.MARCY 1 MISERY

So gEDA had the wrong footprint for an SSOP20 & we had to make a new ground station board. Fortunately it only requires remaking 1 side when your double sided boards are stacks of 1/32" boards.The PIC18F14K50 has USB & programming on the same pins, so in circuit programming is extremely slow without a bootloader & USB probably doesn't work with the programming header attached. You're looking at pogo pins & a jig.Since USB hasn't worked between this week's commutes, probably going to make the ground station radio a breakout board & use a chip with dedicated USB pins as the ground station CPU.

Flight computer ready.

MEET MARCY 2

While waiting for Marcy 1 parts to arrive from Thailand, started the Marcy 2 vehicle. She's planned as a backup indoor sonar demonstrator in case Marcy 1 doesn't work. The parts are all in apartment. Probably going to use the programming pins for PWM.She uses a no brainer 3 gyro, 4 PWM, 1 sonar autopilot. Could have just recycled Vika 2's autopilot but all our indoor vehicles need 900Mhz radio & sonar on the main board. Though capable of flying a tri rotor, Marcy 2 is planned as a tail sitter.The main problem is fabricating a tail sitter small enough to fit in a $1 million apartment.
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MatrixPilot 2.0 Released for UAV Dev Board

Posted by Ben Levitt on December 11, 2009 at 12:40am
What's New in MatrixPilot 2.0
  • Combines the functionality of MatrixNav and AileronAssist into a single firmware.
  • Supports navigation using both ailerons and rudder.
  • Increases the number of Radio Input channels (from 4 to 5), and Servo Output channels (from 3 to 6).
  • Supports controlling Delta wing and V-Tail airframes, in addition to Standard airframes with or without ailerons.
  • More responsive to switching between Manual, Stabilized, and Waypoint modes.
  • Supports using the new uBlox GPS for faster navigation responses.
  • Super-basic camera stabilization code.
  • Adds serial telemetry output in a variety of formats.
    • Supports telemetry output in our own UAV Dev Board format.
    • Supports telemetry output using an Ardupilot Ground Station compatible format.
    • Supports NMEA output to a Remzibi OSD.
During my reorganization of Bill's excellent code base, I've been focusing on making it more configurable, more maintainable, and more easily extendable. So hopefully progress on this project will continue to accelerate! We have a growing group contributing code and testing through our email list, and we suggest that you join the list if you are an active user of a UAV Dev Board!More info including downloads, a budding wiki, and our searchable subversion repository are available on our google code project page.And of course, giant thanks to Bill Premerlani for the awesome hardware, for providing such a strong software foundation, and for tirelessly answering all of my questions.
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Camera setup for my future UAV

Posted by Jason on December 9, 2009 at 2:30pm
My UAV build has officially started. In order to make the whole process easier, I am taking one system at a time. First up is the camera setup. Not necessarily a logical starting point but I have the camera and I can always use it on an RC aircraft until the UAV is done. Also, this gives me a chance to practice with it and tweak.I used a Webbie for the camera. Just remove three screws and carefully pop the back cover off to gain access to the photo and video buttons.

You can see the four wires on the left side of the Webbie (bottom of pic) for the focus and shutter control of still pics. On the right side of the Webbie (top of pic) are two wires for the video control. The "goop" you see is hot glue. I added it to keep things in place and allow the Webbie to function normally if necessary. The hot glue detracts from the surgical soldering job I had to perform in order to add the wires to the small surface mount components. Very tight in there.

I bought the switches I used to control the camera here.

Here I have the camera temporarily mounted to my EZ-400G for testing. I thought testing as many systems as possible on a reliable aircraft was a good idea. This aircraft also happens to have an FMA Copilot on it. It is a very stable platform.

Here is a pic from the first flight test.

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3D Robotics

Summer robotics intern positions at PARC

Posted by Chris Anderson on December 8, 2009 at 10:44am
These are dream internships, at Xerox PARC in Silicon Valley: Autonomous robotics - summer The intern will develop autonomous capabilities for mobile robotic platforms such as unmanned ground vehicles (UGVs) and unmanned aerial vehicles (UAVs). The focus of this effort is on probabilistic algorithms for sensor processing, motion planning, and vehicle control. The overall goal is to develop increasingly integrated model-based motion planning software that uses sensor models, agent models, and models of the physical surroundings, enabling interaction with unknown environments. Responsibilities include: deriving new algorithmic approaches consistent with the applicant’s background; developing them in simulation; and potentially applying them to existing UGV or UAV testbeds as appropriate. Requirements: Graduate student candidates in engineering and computer science Strong skills with C/C++ or Matlab for system simulation and implementation Background in optimization, statistics, artificial intelligence, and control Practical experience in robotics Robotic localization, mapping, and planning - summer The goal of the DARPA-funded LANdroids project is to deploy a team of robotic sensor nodes in an unknown environment to sense and report events to a tactical control center. Our project goal is to create efficient representation for both physical and radio environments, including mapping and localizing a team of robots using radio and short-range sensors. In addition, we are interested in algorithms for cooperative motion planning for physical search and exploration in unknown environments. Requirements: U.S. citizenship or permanent residency is required for this position Strong theoretical background in optimization and probabilistic reasoning -- with practical experience in robotics and good programming skills in both Matlab and C/C++ Graduate students in a relevant field (electrical engineering, computer science, or similar) are preferred, but we will also entertain applications from exceptionally strong undergraduate students with relevant experience [thanks to sonal chokshi for the tip]
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Pretty cheap camera+DVR system

Posted by Ty on December 8, 2009 at 9:54am
http://www.supercircuits.com/Security-Cameras/Specialty-Security-Cameras/RCCAM1?cmpid=136Sorry about the commercial post. Not my company, not affiliated with them in any way.

633857740442265000_RCCAM1-LEFT.jpg

The specs: 3 inches long, by .75 inches wide, weighing in at less than .75 ounces.I'm super-poor, or I'd be trying to pick one of these up (eventually to modify for pan and tilt). If anyone does pick one up, I'd be interested in hearing how stiff the camera head is.
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Developer

Ateryx 2.0 - The happy medium

Posted by Ryan Beall on December 7, 2009 at 3:00pm

Here is something that might peak some intrest. I plan on selling my autopilot in the near future and would like to see if there is any intrest in my product.The autopilot world is hard to attract the hoby level audience because of the steep price jump in higher performance systems. The cheaper approach is to buy the DIY kits and depend upon the opensource code to carry you along. My product is a happy medium between the two.The foundation of the code that comes free with the purchase of the autopilot is capable of keeping the aircraft stable and holding airspeed and altitude. However, if you want to add more features you simply purchase the appropriate app for the job. For example I expect most people will want to purchase the cheap waypoint and track smoothing app. This may seem like overkill but it allows the user to purchase only the capability required to meet their mission thus keeping the price-point more flexible. Apps are listed belowSD memory card loggingWaypoint navigationAltitude terrain followingCamera triggeringWind estimationMagnetic headingCurrent sensor and loggingAutoLandingAutoTakeoffEtc.Ateryx2.0 = $1,000Apps = $800 - 100Ateryx 2.0 has hundreds of hours of flight tested proof in robustness so you spend less time setting things up and more time flying. Purchase what you want and nothing more. Feel free to contact me if you are intrested.ateryx.autopilot@gmail.comRyan Beall
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Developer

Help testing radios

Posted by Jason Short on December 6, 2009 at 5:41pm
Hi everyone, I'm looking for some volunteers to test some code that's part of the 2.5 release of Ardupilot.I'm looking for a wide range of radios and here's the trick: You need to solder a jumper from input 3 to Pin 13 on your ardupilot.I'm sure some people will have issues, so better to catch them now versus the final release. I'm also going to be posting more code snippets to test in the coming week.Here is the file: Ardupilot_radio_tester.zipPlease center you radio trims before you run this so we can compare output. Use the serial out in Ardiuno to see the output.note:Radio model #Receiver model #Ch3 Failsafe settingCh1-3 values when radio trims set to central positionNote,if you can set your radio's failsafe to drop ch3 value below normal, please try that. Also, let me know if that can't be done with your radio.Thanks!Jason
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Developer

Ardu-IMU-Pilot firmware ready for beta test!

Posted by Doug Weibel on December 6, 2009 at 1:30pm
I have completed ground testing on the new firmware I have written for ArduPilot to use ArduIMU in place of the thermopiles. It has been snowing here and I probably won't get to fly the code for a bit, but figured others might be interested in giving it a try at this point. This firmware will probably exist on a temporary basis, with the code getting incorporated into the regular ArduPilot firmware in the future. If there is sufficient interest in this approach I will consider working on a ArduPilot shield board that would add the pressure sensors to ArduIMU and package it all as a shield.

I will maintain the code for a while in a repository at http://code.google.com/p/ardu-imu-pilot/

If you try it out give me your feedback. It is similar to ArduPilot 2.4 but uses a different header file.

To interface ArduIMU to ArduPilot you connect the gps (ublox only) to ArduIMU, provide common power and ground to ArduPilot and ArduIMU, and connect the serial output pin of ArduIMU to the serial input pin of ArduPilot.
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Developer

The Ardupilot FG Control for the Flight Gear Simulator

Posted by Jean-Louis Naudin on December 6, 2009 at 6:00am

The ArduFGControl is a PC application which allows you to test and tune your Ardupilot CPU board with the Flight Gear Simulator. FlightGear is a free and an open source flight simulator developped by Curtis Olson. The ArduFGControl is a gateway between the Ardupilot board through the FTDI cable (com port) with FlightGear through the network UDP ports. The FlightGear model used here is a Rascal 110So, with this application you may test at home your Ardupilot during this cold winter...The full software can be downloaded at : http://code.google.com/p/ardupilotdev/downloads/listTested on Windows Vista SP2 on Intel(R) Core(TM)2 Duo CPU T250 @2.00 Ghz ( perf ind: 4.8 )Have fun,Jean-Louis Naudin

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3D Robotics

Updates from the DIY Drones dev teams

Posted by Chris Anderson on December 5, 2009 at 3:00am
Here's the latest from some of the Dev Team leaders: First, the core ArduPilot team is close to a beta release of ArduPilot 2.5, which is a huge clean-up of the code, with top to bottom improvements. As always, you can get a preview by watching the activity on the Google Code development repository. This team is also creating the code architecture foundations for ArduPilot Mega. The IMU code team is working from this repository. Other projects: ArduIMU thermopile replacement (This is the version of ArduIMU that is intended to be a plug replacement for any thermopile sensor, on ArduPilot, AttoPilot, Paparazzi or FMA. It has no GPS, so it will add a 3-axis magnetometer to get a full attitude solution) Mike Zaffuto: "Magnetometer selected is the HMC5843, it's a good price $20 (qtys of 1), 3-axis, available at digikey and sparkfun, I2C interface and small QFN package like the chips on ArduIMU. The Dual DAC I selected is the LTC2627, I2c interface, 12bits and small 12pin DFN package. The magnetometer will most likely need to be mounted as far back on the tail, underneath, on the sides, inside, as possible to keep it away from the electric motor and wiring. This will be to avoid as much as possible a motor rpm dependency on H field calibration. ArduIMU is very small and can be made even smaller to make the module less obtrusive in this proposed mounting location. I have arduino code to communicate with this magnetometer. It is someone else's code, but good to communicate with just the magnetometer, it needs modification to handle multiple i2c devices on the bus. Nonetheless it is a good guiding framework for a rewrite so that it is original code. " Turn-rate limiter shield (This is the project to make a turn-rate limiter shield for ArduPilot, which will consist of a single yaw gyro. Combine with the GPS, this can be a very simple and inexpensive full autopilot for stable aircraft, eliminating the need for thermopiles or an IMU for that sort of application. This is meant to create an "entry-level" full autopilot solution) Jeff Taylor reports that the first custom PCBs had the wrong footprint for the gyro, so he's using a Sparkfun breakout board for testing while we wait for new PCBs. Lego Mindstorms Universal RC Interface (This is the project to modify the ArduPilot board to be a universal RC interface for Lego Mindstorms NXT: Read RC and GPS data and drive servos vis the NXT's I2C bus) Christopher Barnes: "I've got some robust and generic code running on the Arduino to allow the NXT to communicate with the board so that it can read an/or write any variables that we want to share. This includes Remote Control channel inputs (& PWM outputs), analogue inputs, logic inputs (MUX, Failsafe) as well as any GPS parameters extracted from the GPS messages. (I've been testing with uBlox 5 in binary mode). I would intend to release this software with a general purpose configuration but with clear, commented code so that anyone interested can customise the parameters that are exchanged with the NXT." ArduIMU documentation This is already in good shape, as Andy Geppert reports: "The majority of the sections are roughed in. I'd like to add much more detail (block diagram of the hardware, and one of the software, high level description of the schematic, start-up details, gain suggestions...)." ArduStation Mega (ArduPilot Mega ground station) hardware: Sarel Wagner reports: "I am in the process of doing a version of the schematics. The block diagrams are complete. As you know the case mock up was done. Also working on the data sheets for all components to get the mechanical info for the board layout. Still awaiting some info on the new switches suggested by Scott. Tthe schematic is about 60% done, not in Eagle though, don't have any Eagle skills :/ so need to build a few things first :) I would say we may have the schematic done by late December "
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THIS WEEK IN AEROSPACE

Posted by Jack Crossfire on December 4, 2009 at 11:59am
5 FLIGHTS TO NOWHEREFLIGHT #1The severe wind storm crashed us real good into another roof.Fortunately accessible by foot. Obviously either 40mph wind is abovelimits or you need to tilt the engines.FLIGHT #2Aft propeller wouldn't spin. The crash must have damaged the propellerso it wouldn't grab the crown nut.FLIGHT #3Aft propeller wouldn't spin again. The roof crash stripped the crownnut. Maybe crown nuts can be damaged & have a finite life.

Decided the best move was to make a complete set of new crown nuts.

Since they're not sold anywhere, here's how to make them.

Tin the lock washer & nut by heating for a long time & tacking solder.Eventually the solder naturally flows between the tack points.

Sandwich them together. Remove excess solder with a knife.FLIGHT #4

The wind storm created so much debris, taking off anywhere shredded thepropellers. There was no safe takeoff position anywhere. By then itwas time to get back on our commute.

Finally discovered the lock nuts were asymmetric & the tail rotor wasusing the wrong side all this time. This fact was only visible at highmagnification & makes you wonder what good lock nuts are if they onlylock 1 side.FLIGHT #5With the lock nut issue finished, the tail motor was now stalling & theESC was overheating. Obviously a broken winding. Major Marcy got usback in the air but it was only a matter of time before Chinese qualitystruck back.

The high resolution photos revealed nothing obvious. Swapped ESC's &sure enough, it was the ESC.

A resistor dropped right out. There's the Suppo ESC with missingresistor.

& there it is with the resistor resoldered. Though as marginallysoldered as humanly possible, the Suppo did take a direct hit rightwhere the resistor was.

The aft ESC on Vika 1 takes a beating when landing on concrete.

MORE PROPELLER CRACKS

The latest thinking on propeller cracks is they're caused by a buildupof threadlock on the crown nuts making the plastic brittle.MEET MARCY 1Meanwhile, in brief fits of highly condensed etching & soldering betweencommutes, Marcy 1 takes shape.

The ground station & flight computer. FYI, never blend pads & fillareas.

900Mhz radio modules complete

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Moderator

Very stable and Cheap Homemade Camera Platform - MUD DUCK

Posted by Brian on December 3, 2009 at 8:00pm
I found this company while searching for homemade plane ideas. I've always the "rugged" look of agri-planes so the planes on this site really caught my eye. The cool part is they are built with foam board and are very stable slow-flyer planes. I've included another link to a guy's vimeo site who's big into FPV. He uses Mud Duck inspired planes and tosses up HD video camera. He's got some really nice video posted.Mud Duck Aviation hereMud Duck video here

DawnPatrol.jpg

Paul Thompson Vimeo FPV "Awsome setup" here

Big Breakthrough with HD Pan and Tilt! from Paul Thompson on Vimeo.

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