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3D Robotics

My test platform

Posted by Chris Anderson on August 8, 2009 at 10:00pm

One of the best ways to test your sensors, servos and navigation routines is by walking around carrying the plane. But that can be cumbersome, and there's always the risk that you'll forget to unplug a wire and end up getting whacked by a spinning prop. Also, who wants to program with a plane in your lap for testing? So I knocked together this little UAV simulator. It's just a strip of thin plywood with a little toy elevator and rudder so you can see what's going on. This one has all the equipment necessary for a fully-functional UAV, so I can not only test navigation but also stabilzation, watching the Xbee-transmitted data in realtime with a handheld ArduStation. It's perfect for walking around and testing waypoints without looking like a total dork for carrying around a model airplane (although it's not much less dorky to carry around a slab of electronics and wires). Anyway, if you want to know how the DIY Drones sausage gets made, there you go!
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3D Robotics

New DIY Drones rules

Posted by Chris Anderson on August 8, 2009 at 9:15pm
To keep a bit of order here, I need to emphasize the difference between blog posts and the forums. ALL tech support issues and questions should go in the Forum. Blog posts are ONLY for information of interest to the broader DIY Drones community, such as: -News about UAV, sensors, airframes, R/C electronics, etc. -Successful UAV setups and flights. -Notification of new updates for any UAV hardware/software. Everything related to support, introductions, Ardupilot suggestions and general purpose questions MUST go to the Forums. Person who post in the wrong area will be notified and the post will be deleted (we'll send you a PM with a copy of your post, so you can repost in the right area). Hopefully, this will keep the center column here on the front page interesting to all community members. Sincerely. The Management
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3D Robotics

Tip for tweaking ArduPilot: start without the throttle connected

Posted by Chris Anderson on August 8, 2009 at 6:30pm
I was test flying today in anticipation of a trial for the T3 Contest entry tomorrow. The winds were pretty high, around 20-25 Mph, and the airplane was unable to make headway against them. So I reverted the throttle to manual control (plugged ESC straight into the RC) and made sure that the throttle was always high enough to make good headway. Night and day! The plane navigated great and did figure eights overhead for 15 minutes before I put it back into manual and landed it. Once I've got all the other gains tweaked, I'll start tweaking the pressure sensor and throttle, but for now the best way to test is with a manual throttle. I've added the following text to the manual: "Our recommendation is that while you're first setting up ArduPilot for your aircraft, you do NOT use it to control the throttle. Rather than connecting the ESC through the ArduPilot, connect it straight to your RC receiver as usual. That way you can control the throttle manually while ArduPilot is controlling stabalization and navigation. The main reason for this is that it's very difficult to tune aircraft in the wind, especially if the throttle settings are not sufficient to make headway (when the aircraft is heading into the wind with a insufficient throttle setting, its ground speed may drop to zero, which will confuse the GPS navigation, which is based on ground speed). Manually keep the throttle high enough to make headway into the wind, and you'll find it much easier to observe and tweak stabalization and navigation gains."
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GPS Emulator for ArduPilot with Google Maps

Posted by Paul Mather on August 8, 2009 at 7:30am
Maps.gifNOTE: I released the "magic smoke" today (8/7/2009) on my ArduPilot board, so development of the emulator will be stopping for the next two weeks. I need to order parts and I also need to appease the wife (too many late nights recently playing with my new toy).NOTE: This project is a part of Remzibi's OSD project, please download and install Setup.exe to make sure you have all the necessary DLL's and controls!!!OverviewThis project is used to provide emulated GPS data for the ArduPilot hardware using Remzibi's USB to serial cable. The emulated output will provide feedback for the Ardu's movement commands. It does require a recompile and upload of the firmware to the Ardu so you will need the FTDI cable. The output is then displayed on Google Maps and updated every 5 seconds. Home position and waypoints are shown as well.For info on Remzibi's OSD: www.rcgroups.com/forums/showthread.php?t=921467To purchase the ArduPilot: www.sparkfun.com/commerce/product_info.php?products_id=8785Programming cable for ArduPilot (GET THIS ONE NOT SPARKFUN'S!!): http://store.diydrones.com/ProductDetails.asp?ProductCode=TTL%2D232R%2D3V3ArduPilot Manual: docs.google.com/View?id=ddjmqgw3_43gm6gvggfStraight Headers: www.sparkfun.com/commerce/product_info.php?products_id=116Bind Plug: store.diydrones.com/ProductDetails.asp?ProductCode=AC%2D0002%2D01Getting StartedFirst, you'll need to solder on the headers as shown here: docs.google.com/View?id=ddjmqgw3_43gm6gvggf#2_Preparing_the_hardware_87968. The Emulator will only make use of a small number of these connections, but you'll need most of them when it comes time to fly. You'll also need to solder on the MUX jumper shown in the second photo. For this project, I am not making use of the ArduShield.Next, download the Arduino development environment frm here: arduino.cc/en/Main/Software and unzip it into a folder on your PC (ie C:\Program Files\Remzibi OSD).Now download the GPS Emulator from here: www.happykillmore.com/software/RemzibiOSD/Waypoints/Waypoints.zipThis zip file contains the ArduPilot source v2.2 (modified for use with the GPS emulator) and the GPS Emulator software. Unzip these files into the same folder as the Arduino development (ie C:\Program Files\Remzibi OSD). In the ArduSource folder, you'll find a file called easystar.h. This file needs to be cut and pasted into a new folder in \arduino-0016\hardware\libraries named ArduPilot so the new "full" path will be C:\Program Files\Remzibi OSD\arduino-0016\hardware\libraries\ArduPilot\easystar.h.Next, plug in your FTDI cable and determine the com port. Click Start, Run and enter devmgmt.msc and hit OK. Expand the branch called Ports (COM & LPT). You should see it in the list.Open the folder C:\Program Files\Remzibi OSD\arduino-0016 and run arduino.exe. Click File, Sketchbook, Open and browse to C:\Program Files\Remzibi OSD\ArduSource\ArduPilot_EasyStar_V22 and open any file in that directory. Next click Sketch, Verify/Compile. If you don't get any errors at the bottom, you're ready to upload the firmware to the ArduPilot.Uploading the firmwareNow that everything is compiled, click Tools, Serial Port and select the serial port you identified above. You need to plug the FTDI cable in to the ArduPilot and provide 5V power from a BEC or your radio. You can plug the power in to any of the servo input or outputs.IMG_4943_640X480.jpgNext click the icon labeled "Upload to I/O Board" in the Ardino software. Keep your fingers crossed. It will take about 30 seconds. A good indicator is to see the amber colored light (status light) after 10 seconds will flash for a second and then go off if it's working. See here for details on the lights on the Ardu docs.google.com/View?id=ddjmqgw3_43gm6gvggf#Appendix_1_Correct_LED_behavioThis is a good time to take a break and calm the nerves. Maybe take a quick walk outside to smell the fresh air.... ah.... what a nice day....Setting up Waypoints (temporary)Download the software found here: ardupilot.googlecode.com/files/ArduPilotConfigTool_Fix1.zip.The software is difficult to use in my opinion because the map on the right is utterly useless. You can't click on the locations or even zoom in on any area. All you can do is Click Add Waypoint and type in the lat and long values. It might be helpful to use Google Earth to find these values. You can also try using this: www.happykillmore.com/software/RemzibiOSD/waypoint.html and zoom in to your location. Then you can click on multiple spots and view the tool tips (leave your mouse over the point). It's tedious, I know. Once you get them entered into the ArduPilotConfigTool click Actions, Select Port and select your FTDI cable's COM port. Choose your board style under Actions (probably AT328 if your board is red). Click Actions, Write. Hopefully, all went well. Please note that you did not set your home location during this process. That is done later.Please write down your waypoints. You'll need them later for another temporary work around.More instructions are available here: docs.google.com/View?id=ddjmqgw3_43gm6gvggf#Using_the_Setup_Utility_137125Wiring the ArduPilot for use with the GPS EmulatorTo wire up the USB to serial to the ArduPilot, you're going to need to connect the ground wire to the top left corner (marked GND) or to any of the grounds (marked "-") on the servo input/outputs. The Blue wire goes to TX0 and the white to RX1.Next you'll need to provide 5V power from either your RX/ESC or from a BEC (as shown below). If you have the "old" 4-wire OTI USB to Serial from Remzibi, you can power the board using the red and black in the top left corner.You'll also need jumper the D6 pin to the pin to the left of it (GND). This is the "safety"/set home position jumper. BE CAREFUL not to jumper the GND to the unlabeled pin to it's left. I released the magic smoke from my ArduPilot that way!!!Finally, you need to connect a servo tester or your RX on a channel with a 3-position switch to the servo input labelled CTRL. The down position is normal flight mode (no auto-pilot). Middle position is Waypoint mode (will fliy on auto-pilot from home to all of your waypoints and then back home and will repeat). The up position is RTL (return to launch) / return to home. I'm not sure what it does when it gets home because I fried my board before I could test it.IMG_4940_640X480.jpgEditing the Default.html file (temporary)In C:\Program Files\Remzibi OSD there is a file called Default.html. This is the "template" for the Google Maps output. Please open this file in notepad and edit the lines that look like:var oMarkerLatLong = new GLatLng(41.251576,-81.814974);var oMarker = new GMarker(oMarkerLatLong, {icon:icon});map.addOverlay(oMarker);Please do not edit the first one that has %HOME% in it. This will be replaced by the GPS emulator software. You can have as many waypoints as you want. The Default file has 5 plus the home position. All you have to do is change the values after new GLatLng( to the values you wrote down in the Setting Up Waypoints section above.In the future this will all be automated and selecting your home location and waypoints will be MUCH easier.Using GPS EmulatorNow you can run the GPS Emulator program (C:\Program Files\Remzibi OSD\GPSEmulator.exe). You need to select the right COM port for your USB to serial cable (Start, Run, devmgmt.msc) and 9600 baud and 5Hz. I find it helpful to click NMEA, Show NMEA Output so I can watch what's being sent and what's being received. You'll need to enter your home GPS location (could be the same as waypoint #1 if you want). I'm planning on changing the way the data is entered in the GPS emulator, but for now, you'll need to take the decimal place of your lat and long and multiply it by 60 and enter that. ie 41.251576 = 41 .251576 * 60 = 41 15.09456. I know, I know, that's annoying too, but don't worry, it's a work in progress.Connect the 5V power to the ArduPilot with the D6 + GND jumper attached. With the GPS emulator running (you may have to hit Connect and Start if this is your first time running it) you should see the blue light on the ArduPilot blink very fast and then turn off. Now you can remove the D6 + GND jumper. Now the blue light should come on solid indicating GPS lock. At this point, flip your control servo input to the middle position (waypoint mode) and check the checkbox labelled "Read Data from ArduPilot"....FINALLY! It's flying on it's own!!! You should see the waypoints on the map and a purple line being drawn. The update speed is once every 5 seconds because too much processor time was being taken up by drawing the map and it was making the program crash.In your C:\Program Files\Remzibi OSD folder is an output file called Maps.html. It contains the source for what you were looking at in the output window. A sample can be found here www.happykillmore.com/software/RemzibiOSD/maps.htmlSample.gifEDIT: I'm still making progress without having a working Ardu. This screenshot shows a working drag & drop marker map for setting waypoints and home location. The search function works too!GPS%20Emulator%20Set%20Home.gif
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Tilt compensated compass algorithms

Posted by Tim Trueman on August 7, 2009 at 4:45pm
This Sparkfun product does it with 3-axis magnetometers + 3-axis accelerometers: http://www.sparkfun.com/commerce/product_info.php?products_id=8656I have both 3-axis magnetometers and 3-axis accelerometers but I'm unsure what algorithm I could use to get a steady heading output. Any ideas?(I also have a 3-axis gyro and Kalman filter running so I have pitch and roll--although I can't seem to debug why pitch is laggy and roll is instant with the exact same code.)
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Accelerometer question for IMU Experts

Posted by Roy Brewer on August 7, 2009 at 8:09am
I'm sure there's plenty of experienced IMU builders on this board who can resolve this question (see here: http://www.diydrones.com/forum/topics/gyrospes-vs-acceleometers?x=1&id=705844%3ATopic%3A85220&page=1#comments (starting at the 5th comment) and here: http://www.rcgroups.com/forums/showthread.php?t=1066119&page=30 (starting at post #443) for more discussions). In fact the question may even have been answered here earlier (in which case I apologize for re-asking it, but I couldn't find it). The question has both a practical aspect in terms of IMU component & s/w design and a theoretical one in terms of trying to understand the relevant physics. Read carefully, because I don't think this is a noobie question.Assume a 3-axis accelerometer is mounted close to the center of gravity of a quadrotor with the Z axis of the sensor aligned reasonably well with the thrust axis of the rotors and the X and Y axes aligned with 2 of the arms of the quad. If the flying quad is at a non-zero bank angle (i.e. is rotated about the x-axis from a level hover), what will the Y axis accelerometers read? In this case, the vehicle will be accelerating laterally in the earth axes (and possibly vertically depending on the magnitude of the thrust vector compared to the gravitational one). One school of thought claims that the Y accelerometer in this case should read effectively zero (assuming that aerodynamic drag, vibration due to rotors, noise, errors due to sensor misalignment, coriolis and centripetal forces, etc. are either negligible or accounted for). The reasoning is that all the forces should be coming from the rotor thrust, which is always in the Z body axis for a quad. By a similar argument, the X axis accelerometer should also read zero for any pitch angle. (I think the argument holds to some extent for helicopters as well, but the force vector will not always be in the Z body axis direction due to rotor flapping.)The opposing argument is that there are plenty of quadrotors out there that use accelerometers to self-level, perhaps as part of a Kalman or complementary filter algorithm. It would seem unlikely for them to work as well as we know they do if the X and Y sensors were reading zero regardless of the vehicle tilt. How do we resolve this conundrum? Is the model of how accelerometers work flawed? I believe it is valid to model the resultant output of any accelerometer by determining the net force and subtracting the gravitational force vector. This works if the sensor is stationary (it will read as if it were accelerating away from the ground at 1 g), or if it is in free-fall (reads zero). Is this model correct in general for arbitrary motion? Are these other forces on the quad that I'm ignoring important somehow?I'd prefer if your answer includes one or more of the following: time history graphs of a FLYING vehicle (we know we can measure tilt of a stationary sensor), or a free body diagram, or a set of equations, or a reference to a textbook or paper. As I said, I'm trying to understand the physics of the situation.Here's a picture, if it helps: http://www.diydrones.com/forum/attachment/download?id=705844%3AUploadedFi58%3A91201 This shows the forces in the earth vertical axis as being balanced, but I don't think that condition is necessary for the X body axis accelerometer to read zero.Thanks in advance.- Roy
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What to do with 2 weeks in Canada and a UAV Budget

Posted by Ross Badcock-Walters on August 7, 2009 at 3:28am
Hi AllMany thanks to all of you who helped and especially Rory Paul. I managed to use the info for a presentation and now have an "angel investor" / business partner, and we intend to run an Aerial Phography business for Agricultural Developement projects in Africa. We are going to Canada at the end of the month to meet the guys from Aerial Insight. Do some training, and hopefully purchase a AUV. We would also love to see the country and meet people who are doing interesting projects in related fields. If anyone has any ideas or suggestions I would really appreciate it.RegardsRoss WaltersAgricAir, AfricaDurban, South Africa
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armature

Posted by shailendra singh on August 7, 2009 at 12:06am
hai...........i m persuing b.tech.3rd year with a a little knowledge of aeromodelling and a deep knowledge of advance robotics i had planned to make a uav and had planned fully to make it but nervous and confused from where to start.please help me .i had planned to use a gps nodule and atnega 64 to control aircraft om auto pillot mode.please tell me the use of compass and gyros and can the speed of engine can be controlled.i also wamt to know the avalibility of engines ang servos in lucknow and delhi
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Ok im back with the same problem ( no manual control)

Posted by Patrick Mccabe on August 6, 2009 at 4:05pm
Yup i fixed it since last time. They said it was the round headers that were not making a good connection. Well i got square ones and they are now tight fitting. So why do i have a problem? Ok im using 2.0 code which loads fine no z sensor or expansion shield. 2.4ghz 6ch transmitter and receiver already bonded and i know they are. I dont i have the ESC plugged in and am using a UBEC to power the receiver and board. Ok so i believe that everything is plugged in right and the lights are right so i dont know whats the deal. I know i didnt calibrate the sensor but that shouldnt effect the manual mode. I should always be able to have manual control when switch on and i dont. I doubt that will fix UAV mode too which is also not working. I made a video like last time so the link will be below.Thanks for any help :)ok here is the video
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Cheap Trainers

Posted by Robert Drone on August 6, 2009 at 3:00pm
I know you've all heard of the easy star but what do you think of these? Are any of these any good? I picked them because they look decent but don't cost as much as the easystar for starting off with plain old flying [drone comes next]. If you know about any of them or any better ones please comment! Thanks!-Rd=]j3club

j307.jpgwildhawk

yhst-17210252890263_2062_66591631Aerobird Swift RTF

31lLk%2BX3DxL._SL500_AA280_.jpgAerobird 3 RTF Electric

31o4Wxnfk4L._SL500_AA280_.jpgFirebird Commander 2 RTF Electric

31NV9VEYBCL._SL500_AA280_.jpgFirebird Freedom RTF Electric

31V5BX5ZPCL._SL500_AA280_.jpgAre any of these any good? I picked them because they look decent but don't cost as much as the easystar for starting off with plain old flying [drone comes next]. If you know about any of them or any better ones please comment!
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NASA blog 4 U

Posted by Jack Crossfire on August 6, 2009 at 2:30pm
http://blogs.nasa.gov/cm/blog/CASIE4 those of U who want to know what it's like to operate a fixed wing UAV professionally, this is a good read, after work. U think a few thousand bucks in a tried & true fixed wing gets U a bulletproof hands off system but it doesn't. They have to watch for icing in flight, check weather before flight, verify thousands of systems, troubleshoot glitches, fix balky radios, & test fly before the actual mission.This is all after the grants are awarded, the debt is monetized, & the gear is at the location. The autopilot is not from Shenzhen KDS or Shenzhen Dajiang Innovation but Oregon of all places.They use the same Goog Earth tools U do. Their aft mounted propeller gets damaged by rocks thrown up by the landing gear. They take off & land manually using 2.4Ghz RC controllers before switching to autopilot. When was the last time U did a manual takeoff? They use iridium satellites for long range radio. They still cross their fingers every time they fly beyond line of sight.Like all grad school, the real challenge is not designing the experiments or solving difficult equations but troubleshooting sensors, swapping dead batteries, & stopping water intrusion.
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Code wont load

Posted by Ron Carter on August 6, 2009 at 10:31am
I have been trying all week- probably 20 hours so far to get the ardupilot code to load correctly. I have checked my driver installation countless times. emailed Mr Anderson several times, called FTDI and talked to customer service, had assistance form a CS grad all with no progress. I am extremely frustrated and am willing to pay if neccessary to get this !@#$%!! thing going.It appears as though the processor will not process any code because the very top line of code is "not declared in the scope" of the program. At one point we reordered some code and got the same error on the new line of code. This indicates to me that something really basic in the program is not being recognized.Any help would be greatly appreciated.ThanksRon Carter
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Developer

Launching an ArduPilot Project with my daughter

Posted by Doug Weibel on August 5, 2009 at 4:53pm
Hello All,I have started into an ArduPilot project to satisfy my curiosity and to draw my 12 year old daughter out of her novels and into some practical math and science. My intent is to start with a straightforward ArduPilot set-up with the current hardware and software.The airframe I chose is the SuperStar EP. We finished assembling it last night. It is stock (for the present) except I am running a 3 cell 2200 mAh LiPo instead of the stock NiCad. With 200 grams less weight and considerably more voltage the SuperStar performs quite nicely. We are just back from 2 quick flights at the local schoolyard. My daughter learned what happens when you land in grass that is 4 times as tall as your tires :)Tonight we will begin assembling the autopilot hardware. Again I am going with the "stock" setup - DIYDrones IR sensors and shield with airspeed, and EM406 gps.I have not ordered parts yet for downlink and groundstation. I was not planning to implement that right away, but judging from some posts I have seen it may be highly desirable for debugging purposes. I'd appreciate any opinions on that as well as on using the hardware ground station versus a laptop setup.Best Regards,Doug
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T3

Recommended DCM algorithm gains for red UAV DevBoard

Posted by William Premerlani on August 5, 2009 at 1:37pm

09038-1_i_ma.jpg

UAV DevBoard Pilots,If you are using a version of MatrixNav or AileronAssist on a "redboard" that was released before August 5, 2009, there are a couple of revisions that you can make that will improve overall performance.First, you should modify the definition of RADPERSEC in the file optionsRmat.h to:#define RADPERSEC ((long long)5632.0/SCALEGYRO)Just change the definition of RADPERSEC that is already there.In the previous releases, SCALEGYRO was not included, so the scaling in the centrifugal acceleration compensation was correct for the green board only. Many thanks to Sid, who was never quite satisfied with the high acceleration behavior of the red board firmware, for motivating me to find out why. If you include SCALEGYRO in the definition of RADPERSEC, you will improve the performance of the red board firmware for high acceleration applications. Green board firmware will not be affected.Also, you should modify the rmat.c file to use the following values of the drift correction PI gains:#define KPROLLPITCH 256*10#define KIROLLPITCH 256*2#define KPYAW 256*4#define KIYAW 32Just edit the definitions that are already in rmat.c to use the above values.Based on a lot of simulations done by Paul Bizard, and a lot of flight testing by Sid, we have concluded that these values will produce the best performance possible for the red board.The gains in the first release of the firmware for the green board are very low. Although these values provide great accuracy for the green board, when I designed the red board, I was concerned about the security of locking, particularly with the 4X change in the gyro gains, so I decided to use much larger gains for the red board.The gains in the released firmware for the red board are very high. Although this provides secure locking, it is not as accurate, leading to pitch and roll errors during rapid turns at high speed.The latest values provide a much better compromise between accuracy and security.The changes described in this post have been included in MatrixNav and AileronAssist release 1.5, August 5, 2009.Thanks again to Paul Bizard and Sid for their hard work.Best regards,Bill
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Developer

ArduStation code V11 now available

Posted by Jordi Muñoz on August 4, 2009 at 11:00pm

You don't have an ArduStation yet? Came on, buy one now!Well the 80% of the work was made inside. So whats new?-I fixed the issue with the buzzer that sometimes used to drift.-Now you can record the home position and stays even if you disconnect the unit. This function will let me do many things with the board.-Now you can see the 2D/3D distance, direction and the altitude angle of your aircraft. This info will let me control the antenna and will help you spot your aircraft in the air.-I added a tiny and very funny arrow (like the OSD's) that indicates the heading and the waypoint bearing of your aircraft.-Added the new RSP = Roll set point variable, for debugging. If the value is positive means your aircraft is trying to turn right, if is negative is trying to turn left. This is the actual value coming from the navigation function and telling to the stabilization (autopilot) where to go.The next addition is the directional antenna, I'm just waiting for the material.

For those who don't know the meaning of the data, here it is:WP# = Waypoint NumberCRS = Course over groundBER = Bearing (the direction of the waypoint)GSP = Ground SpeedASP = AirSpeedALT = AltitudeRSP = Roll set pointThe code is locate here:http://code.google.com/p/ardu-station/[UPDATE] I forgot to mention that you need the replace (update) the folder called "LiquidCrystal" (is an arduino library for the LCD). The new library folder is included in the same file of the ardustation code,inside "libraries". Then just copy/paste it into the arduino IDE: "\\arduino-0016\hardware\libraries". You are done!Enjoy!

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3D Robotics

Thoughts on a commerical Lego Mindstorms NXT autopilot

Posted by Chris Anderson on August 4, 2009 at 10:28pm
I got started with amateur UAVs by making a Lego Mindstorms autopilot two years ago. It was a total kludge, using a mechanical assembly with Mindstorms motors to move the rudder, with stabilization handled by a FMA Co-Pilot. Originally, I used a compass sensor for steering, but quickly upgraded that to a Bluetooth GPS module. It worked, sort of, but then I decided to go all the way to a 5DOF Lego IMU, using some protoype Hitechnic integrating gyros and a RC MUX. Unfortunately, HiTechnic decided not to release those products, and I stopped development. (Although Sami took a version based on commercially-available gear further than I did--see photo above--he too stopped before getting it totally working). Now I'm thinking of coming back to Mindstorms. Not a full IMU-based one (the cost, weight and size of the sensors, interface boards and other necessary equipment is several times that of custom hardware like ArduPilot), but rather a navigation-only autopilot that could work with a FMA Co-Pilot to make a very simple UAV for kids. What we'd need is a custom interface board that performs the following functions: 1) RC MUX, to switch control from RC to Mindstorms and vice-versa 2) Servo driver (at least two channels--rudder and throttle--but ideally more for photos and other triggering). Here's one example. 3) A GPS interface, so we don't have to use Bluetooth Mindstorms uses a I2C interface. My sense is that if I can just add a Mindstorms connector to ArduPilot and figure out how to handle the I2C communications between it and Mindstorms, it could serve as that interface board. It would send GPS information (already parsed) to Mindstorms, and then Mindstorms would send servo information back to ArduPilot. What's the point of the Mindstorms, since ArduPilot can already perform all those functions itself? Just that it's a more kid-friendly programming environment. If we could treat the custom ArduPilot board as a plug-and-play preprogrammed device that spits out GPS data and accepts servo commands, students could focus on simple navigation logic and action controls. What do you think? Is this a good idea and worth the bother? Or should I simplify things even further and just use the Mindsensors board as a servo interface, Bluetooth for the GPS interface and a touch-sensor as the MUX (like this)?
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3D Robotics

Landing tech could let drones see like pilots

Posted by Chris Anderson on August 4, 2009 at 10:16am

From Wired's Danger Room: "One big difference between Army and Air Force drones is that the Air Force’s robo-lanes can’t land themselves. That’s contributed to a number of Air Force Predators crashing when humans run into problems. But there may be a way of providing autolanding capability without the weight and expense of conventional systems. Computer vision company 2d3 is developing a new system to allow drones to see their way to a safe landing, using their own cameras rather than radio beacons or radar." Read the rest here.
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3D Robotics

Helicopter autopilot with optical flow sensor

Posted by Chris Anderson on August 3, 2009 at 11:24pm
Spotted in the Model Airplane News magazine: an ad for "Flymentor" from Shenzhen KDS Model Technologies. It's a gyro-based helicopter stabilization system with an interesting twist. It includes a CCD camera that looks down, capturing "a ground picture" and holds the heli in one position, presumably by using optical flow. It's kind of amazing. Don't ask me how it holds altitude, but it does, very well, as this video shows:
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Changed the 2.1 for 2.0 hardware features.....

Posted by Vikram on August 3, 2009 at 9:04pm
Hi all, i m ready for the ground test.Before starting i would like to clarify few things here..I dont have Z sensor and air speed sensors soofcourse no throttle control then also... I was ok with version 2.0 but since i would like to add the config utility feature without increasing any hardware. So i made few changes in 2.1 version so that it can work successfuly with 2.0's hardware(only XY sensor).I have made these changes please confirm is it right and please tell me if any other change need to be done. Just remember i want to add config utility in 2.0...So these are the changes i made:1.#define SHIELD_ENABLED 0 //in main file#define SENSOR_Z 0 //in main file// i defined them as zero2.//infrared3= (infrared3*.99) + ((float)analogRead(3)*.01); //in Sensors filei commented this line because i dont have air speed sensor3.(in sensors file)#ifdef SENSOR_Z /// added a new linethrottle_set_point=PID_throttle(air_speed_hold, airSpeed(), t_dt);pulse_servo_0((throttle_set_point));#endif /// added a new linesensor_z();// unbias_airspeed(); //// commented this line here----------------------------------------------------------------These are the changes i made please tell me which loop enables the configutility so that i may try another way just add that function in version 2.0.
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