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3D Robotics

Move to start a civilian UAV association

Posted by Chris Anderson on July 31, 2008 at 11:02am
[From the CropCam googlegroup:] From: Greg Lewis - ODIS [email redacted] Date: Thu, Jul 31, 2008 at 12:04 AM Subject: International Civilian UAV Users Group? To: Cropcam Hello All, We are just finishing up the latest CropCam training session and there has been some very good dialogue. One of the things that we have been discussing is trying to gauge interest in forming an International civilian UAV group. In talking we think this would be a great opportunity to work as a collective group to start looking at and developing a certification program for civilian UAV "pilots". Regulations will be coming, being proactive and self regulating may help pushing things in the right direction when individual countries are developing their regulations. It would also be a way to verify that UAV operators who have this certification meet at least a minimum standard of competencies and follow standard operating procedures, etc. As well, having a conference with this group would allow users with the same objective of using UAV's for civilian purposes to interact. We could share ideas, develop standard operating procedures, etc. I know there are UAV groups but I don't know of any that are civilian specific, if there are any that might already be serving this purpose could you please let me know. Would other users be interested in participating in a group like this? I truly think that organizing ourselves and being proactive in setting standards and sharing ideas, would help safely move the use of civilian UAV's forward. Thank you, -Greg- [Thanks to Jeff Johnson for the pointer]
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3D Robotics

FAQ: What's the difference between a UAV and a RC plane?

Posted by Chris Anderson on July 31, 2008 at 9:46am
I get this question all the time from newcomers, so I'll answer it here as we build a proper FAQ: Q: What's the difference between a RC plane and a UAV? And why doesn't the AMA allow UAVs on its fields? A: The generally-agreed distinction is that UAVs have the capacity for autonomous flight and navigation. A RC plane becomes a UAV with the addition of an autopilot. The AMA doesn't allow UAVs because its insurance doesn't cover them. I actually agree with the policy, since our UAVs are by nature experimental and sometimes out of control. We're pretty careful to test away from people.
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3D Robotics

Housekeeping note: how to send private messages

Posted by Chris Anderson on July 29, 2008 at 4:11pm
If you want to communicate with another member but not necessarily in the forums or their public pages, you can send a private message. The feature is marked by a little envelope, but initially you will only see it next to the names of site administrators (me and a few other people). If you want to send a PM to someone else, you have to "friend them" first, which is to say you extend a friend invitation to them and they accept. You should then see an envelope icon next to their name at all times, and you can PM them at will. Ning imposed that restriction last year to cut down on PM spam. It's kind of a pain, but you can probably see why it makes sense.
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3D Robotics

Cool AttoPilot feature: relative waypoints

Posted by Chris Anderson on July 29, 2008 at 3:29pm
Dean Goedde has added a cool feature to the forthcoming AttoPilot: relative waypoints. He explains: "I have innovated a new method for using waypoint paths: a method to signify a waypoint list as being a "template". In this method, the waypoint list becomes a list of relative coordinates, relative to the 0th WP in the list as an "anchor" that is translated to the actual coordinates of where you happen to boot up the system and get first GPS lock. This way, you have a template type WP file on the SD card of up to 100 WPs, perhaps specifying a 1x1 mile grid with 200 meters between the tracks. You also have an extensive set of triggers defined in this WP template, as to snap a photo every 200 meters along the straight tracks. You boot up in the bush somewhere, fly the path, pack up and move 2 miles away and repeat, ad infinitum. An entire day of Geo mapping with no laptop at the field, and TONS of detailed LOG data for exact location and position of the plane during each photo. The math for converting the relative coordinates takes full care of the actual latitude and how to compress/decompress the longitudes from real-->relative-->real coordinates... path is precisely the same either on the equator or at 85 degrees North." We've been thinking about a similar approach for a supercheap UAV for kids that would just fly selectable patterns around its launch position: figure 8s, squares, circles, etc. No programming required, and potentially no FAA issues since the waypoints are not programmable. Our unofficial motto: "Turning the military-industrial complex into a toy" ;-) Interestingly, Dean has also created a "synthetic" NMEA GPS sentence for telemetry data, which is just what Jordi did with his GSP parser. Jordi's was called the "$JORDI", Dean's is called "$ATTO".
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3D Robotics

Anybody know anything about this very nice-looking autopilot from Poland?

Posted by Chris Anderson on July 29, 2008 at 12:30pm

Ryszard Arandzikowski, a superdedicated hobbyist in Poland, has spent the last three years creating this suite of UAV technologies. Autopilot and ground station software, two-camera pan-tilt system, a really nice looking custom aircraft, and more. Amazing accomplishment for a single person. I've pinged him to see what his plans are for distribution (sell? open source?) but in the meantime does anyone know anything about the project?
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3D Robotics

Easy Glider Pro (and new Multiplex Mentor) now available

Posted by Chris Anderson on July 27, 2008 at 10:30pm

For those who love the Multiplex EasyStar but want more lifting capacity and space (or just need ailerons) good news: its big brother, the Easy Glider Pro, is now available. This upgraded plane apparently fixes some of the problems with the earlier Easy Glider's wing attachments, and is now designed for a brushless motor. Mutiplex also makes a power pack for it, with motor, ESC and prop. I have to admit that my heart is still with the EasyStar, with its above-wing pusher prop leaving unobstructed space for cameras and other equipment in the nose, but if you must have something bigger or need ailerons, the Easy Glider Pro now seems like a good choice for the glider form factor.

BTW, if you want a more traditional high-wing trainer as a UAV platform, while still made out of the virtually unbreakable Mutiplex elastopore foam, you might be interested in its new Mentor (shown below). It's got a 65" wing, and seems perfect for UAV purposes; indeed Jordi and I saw a few used for just that at the AUVSI show.

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Today is a "work" day

Posted by Genesis Factor on July 25, 2008 at 3:30pm
@ 1:39PMSo...after sitting outside for about 30 minutes, i'm pretty sure that the antenna on my GPS is shot. I don't know how or why, but it sends NMEA 0183 nicely, but it doesn't seem to like picking up sats. It blinks a few, but nothing steady or strong. I was using my BT for testing purposes, but it failed, so it looks like i am up for purchasing something else. Maybe something else with WAAS. Nothing 5hz though as my software doesn't want to sample that fast lol.My box from all the people came. Of course, i went straight for the Surprise box. I think this is the highlight of shopping from them. You know you got something interesting when you drop the box on you couch and it starts making strange screaming noises for about 30 seconds. Turns out there were some circuits like in those noise maker cards. That should really get my little brother going... But that wasn't the only thing there. Turns out, that there were more Wacom pens, this time including the point, and these Zoran/Oak Technologies Integrated DTV chips that looked brand new. Apparently, they are used to get HD and SD signals, while processing the audio, and are generation9 chips. http://www.avsforum.com/avs-vb/showthread.php?p=5284893#post5284893I got a whole bunch of them, so i think they will hit ebay as a lot. There were other cool things, but i just got the box, and then realized its time to go to work...After talking to my hobby store, it turns out that i can make the left and right ailerons independant. Doing so makes them act like flaps. I find that very...desirable.I started looking back into Pico ITX. sadly, at 250, it is WAY over my budget ATM. Very saddening. I have to wait till someone puts one up for cheap lol. They are tiny though...and, sadly, more powerful than my VIA. They still look great though.@6:36Spent the ENTIRE time making a damn 5V to 3.34V converter with htat LM317 HVP. Took me hours to find the right resistors, then hours to solder it up together. I'm using a circirt write for the last part and i may have jumped my last soldering point. bah. Not only that, but i BURNED MY HAIR. Did you know that burnt hair doesn't smell good good? i need to get a new soldering point. The one i'm using now is a wedge edge and i need a pencil point. Sigh...atleast now i can possible read my Altimeter.In other news, i think i got myself done with reading the GPS through VPL. Now i just need to take those values and use them to go to waypoints. I probably will code that for the rest of the day. Trevor Taylor is starting a new blog, i'd like to think at my request. Yeah right. He's been an invaluable help thus far. i just hope he doesn't get sick of me!http://blogs.msdn.com/trevor_taylor/I downloaded this interesting GPS tracking program while testing my GPS.http://www.gpstm.com/I just thought it was interesting.@9:49Just bought a new gps. WAAS, here i come. 54g, titanium shell. yay me. It will be here tuesday or wednesdayWorking on the GPS code. I now have working variables that contain the course, heading, lat, long, alt, and velocity. This means i can start on my drift code eventually, as well as program in waypoints and stuff. I'm approaching a point where i can start to visualize my base station GUI and work on it. I still need to get some really good topographic maps though. Being 17M about mean sea level means nothing if you can't comprehend that that means that you're on the ground if you're in my yard. Well...it does mean when the ice cap melts, you'll be WAY under sea level... Has anyone gotten the GPS to work with a Topo map? I figure simple subtraction should get you your altitude above the ground--and simple vision can get you above the tree line!
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The 1 month report

Posted by Genesis Factor on July 24, 2008 at 10:30am
Written on the 20th

Right now, the computer system is almost complete. After numerous discussions on the phone, PC104 boards were added, omitted, and sometimes stared at blankly. The end result is that there is one more PC104 board that had been expected. I guess it was an acquiesce where I wanted to get USB2.0 and was planning to buy an adaptec PCMCIA adatper to go with a dual PCMCIA PC104 board I had. I then found out that ISA bus only has 15.7Mbytes/s (actual power of 2 value, not some 10 based, rounded one), which, well, is not quite much more than the 12mbps of USB1.1. Saved myself $14. That's a lot of money. That's a V-Tail mixer right there. So in the end, after calling Sensoray, and asking them about the 311 framegrabber, which I have 6 of, it came down that logically I need two to accomplish what I wanted, which was dual video in at 30fps. The tech guy was actually VERY helpful, giving me free software links, such as VLC, and explaining bitrates and memory calculations and what not- even telling me that the USB2.0 idea wouldn't work due to the bandwidth of ISA- which ended up being very, very true after some independent research on my part. End result is this: at the best quaility video, which is 640x480, I get (640x480x(3 pixels for color))/8 bits/bytes= 115,200 bytes per frame. 30 frames each second = 3,456,000bytes per second of memory is needed for each frame grabber, or 6,912,000bytes a second on video alone, maximum. These are actually really high quailty, uncompressed images, so i'm not complaining much, especially since that leaves 9Mbytes/sec to do control a 2 axis stepper motor controller. I think it can manage. And what's my last PC104 board? A power supply. Sure, you might think its a waste of a slot, but its a 50Watt PSU and has power out at +12V, +5V and -12V and -5V. I have no idea what I can use the negative stuff for, but i'm sure i'll have fun trying to find something that needs -5V in. :)Bold idea for video recording...As for software, the Sensoray Support guy told me, that for streaming, I can encode using VLC on the onboard computer and capture using VLC on the client side, while viewing the stream. This helps because VLC is free. I like free. Cheap is good, but free and feature filled rocks. Also, he told me that if I wanted to capture a frame, the sub megapixel raw image data of each frame will be in memory for 1/10th of a sec. This means that I can just copy that memory data form that address to another one to save to the hard drive. This will give me a high resolution picture of what i'm viewing for retrieval while a realtime low resolution stream is simul-cast to the client basestation. I guess I can record the massive ~7Mbyte/second recording of the flight on board as well without killing the computer too much, if I really really wanted to. The good news is that chances are, it won't be that big. The resolution of the camcorder is not VGA. In fact, the FPV CCD has a better resolution and larger CCD than the panoramic view. Also the FPV view isn't going to be as important to me as the panoramic camera, so I can get away with shrinking the view a good bit, to maybe QVGA (320x240x3/8)or a bit under a megabyte per second. What this means, basically is that at my realistic highest quality, i'll probably be looking at 2 to 4Mbytes/s- and that is IF my VIA processor can handle it. Kinda missing Intel or AMD right now...Also on the software side, I will be exploring URBI. After seeing how it functions, and wieghing the pros and the cons, the best I can say is that unless I get the full engine and studio, it will have to be relegated to sending and receiving messages from sensors and MSRS, and some vision tracking. This decisions comes pretty hard after seeing that this software can see where faces are and track points in a video and gives me TCP/IP messaging, but its lack of true NMEA decoding, the 1ms per instruction, the fact that to get the full benefit, and the fact that after a weekend of trying with my friends, we STILL haven't gotten URBI to communicate with the local machine, means that, although its a great piece of software, its not a solid fit for this application, but is a SOLID addition for over network communications.Let's get back to the computer...Samtec sent me the cables, and i'm really happy that I called in the day they were made and asked them to lengthen the cables by 1.5” I should have added another half inch, but whatever.

DSC03190.jpgAs far as the computer goes, i'm separating it into 3 modules- Computing, Vision, and Motion. This move into modular organization started with the desire to not have a 3” high computer stack and the idea to spread the weight along the fuselage instead of some crazy 1.5-2 pound point mass. Hopefully this helps the plane's structural integrity.I will be running XPlite as certain option I want to play with are found only on XP. Being the resource hog that XP is, once I get everything going well on the system, i'm cutting out almost all the fat I can to make it as memory thrifty as possible. As long as I have a dedicated 15MB of memory for the video saving, 10 for streaming, and 30 for robotic control,g I will be happy. Out of 256MB, that leaves 201 for whatever fluff MS wants to have for .NET, and support services. If this sucker won't cut it, the PC104 devices and all software are cross-platform and should work great on linux, however I really REALLY wanted to play with some topo mapping software on this...The emergency parachute arrived early last week. Its light, looks strong, and took my 30 minutes to untangle. At 54”, it means my plane will hit the ground at ~15 ft/sec in the event that things happened. I haven't decided whether to mount it on the top of the plane, so that it can land on the landing gear, or on the bottom, so if the computing system breaks off if the plane cracks in half, the really good stuff is safe.

IMG_0774.jpg

The GPS I have, the ZYX-GM11-5U, in its shell, is waterproof, magnetic, and heavy. After removing the shell, it became very, very light. However, I just found out that it doesn't have WAAS. I guess I can't complain, as it was a freebie from a trade...Incoming...On order, and incoming, are several support components. The first was the gear system for the stepper motors to actuate the CCD. I had been staring at it for a while, but I didn't want to get it until I had more stuff to buy because there is something about paying more for shipping than for the item that gets under my skin, even if the item is at a steal of a deal price. I did find, Friday, the day I ordered, an identical pitch gear that will let me use my .06”, or 1.59mm, shaft with these gears, which have a 1.9mm bore. In other words, the hole is too big. Also, from surplus she is an acrylic dome. This is appararently clear gold, as, funny enough, these things are HUGE sellers at Surplus Shed and God was good enough to make me wait a day to order the other stuff. I was told that they would sell out in a couple of days and they JUST put them on. The best part is, that it is just the right size for what I wanted to do. The others that used to be on there weren't. Speaking of which, let me get into that...Attached to each stepper motor will be a that gear that fits, which will then spin a 1.9/2.0mm axle and work the Pan and Tilt. To make sure that the stepper motor will be affected by the wieght, or lack there of of the lens system or the whole camera body, I will be using worm gears right after the adapting gear. This means at the high speeds, if I want to do a rapid rotation, the torque of the stepper motor doesn't need to be anywhere as high as it ought to me, which is good because the faster you accelerate your stepper motor, and the faster you go, the lower your torque is. If you accelerate too fast, you can actually skip, or jump steps, making your readings inaccurate. Also, the worm gearing, would allow for precision movements. The stepper motor that I have does 20 full steps per revolution. This means, using ¼ stepping tricks, I have an 80 step resolution per rotation of motor shaft. Gearing it down, depending on which gears I end up deciding to use, I can really rack up the resolution to, hopefully a degree of rotation per step, which is nice. Not bad for a $4 stepper motor system. What makes it really great is that when I program the camera to track a certain GPS location, using the compass and altimeter, it can actuate the camera with pinpoint accuracy. The optical acrylic dome will be used to make sure that no camera motion translates into unintentional rudder motion:)Finally on order is a LM317HV adjustable voltage regulator from Electronic Goldmine. Mark was nice enough to go over how do to the equation, and I have a bread board set up ready to solder when it arrives in a week. This will take the +5V in from the PSU and make it into 3.3V for my logic level converter ($1.95 @ sparkfun), which lets my 5V parallel port talk to my Altimeter with limited fuss. The helping hands that I got from them in my last order was a BIG help thus far with soldering. I've actually grown to enjoy it. I did pick up a small super solar panel just to check it out, for adding solar to future UAVs, and some micro motors that fit on the head of a dime. What will I build with those motors? I have no idea. The they are tiny tiny! Oh, and after I found out that the two funny looking pens in the Big Surprise Box were $70 Gateway Stylii for the Wacom Based Tablet PCs, you know I picked up another one:).Lastly, I have to order the Vtail mixer. MX80, virturally no stepping.I have yet to weigh the computer stuff as it has changed since we started. However, I hope everything will be light. There isn't much fat left to cut. I changed lenses, lowered batteries, adjusted components...there's not much left without throwing out whole assemblies.
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Lithium Polymer Batteries and Chargers mini-primer

Posted by Cory on July 23, 2008 at 11:04am
Lithium Polymer batteries are an attractive power source for electric flight due to their high energy density. The combination of lithium polymer batteries and brushless motors now rivals glow power in terms of power and duration.The main difficulty when using lithium polymer batteries is choosing what batteries and charger to use. Batteries are specified in terms of voltage, capacity, and discharge rating.Voltage is generally listed as 1S - 6S. The S number refers to the number of cells connected in series that the pack uses. You can calculate the nominal (mostly discharged) voltage by multiplying the S number by 3.7 volts, so a 3S pack has a nominal voltage rating of 11.1 volts. Fully charged, each lipoly cell will measure 4.2 volts, so a fully charged 3S pack will have measure 12.6 volts.Capacity is measured in Milliamp Hours (mAh). So for example a 2000 mAh 1S pack can be expected to provide a voltage of 3.7 volts at a current of 2000 mA (2 amps) for 1 hour. In a nutshell, more mAh is better (and heavier).One of the more confusing specifications is the C rating. The C rating refers to the maximum sustained discharge rate that the battery can tolerate. The formula is 1/C hours. In the example above where we discharge our 2000mAh 1S pack using a 2amp load for one hour, we are discharging it at 1C. If that pack is rated for 20C, we could discharge it in 3 minutes (1 hour / 20C = 60 min / 20 = 3 minutes) with a load of 40amps (20C * 2000mAh = 20 * 2A = 40A). As I understand it, lipo packs should be charged at a maximum of 1C; so 2 amps maximum charge current for the pack in the example above.The main drawbacks to lipoly batteries are cost and sensitivity to abuse. Now your pack may not burst into tears if you insult its paternal lineage, but it may explosively combust if charged improperly or if it becomes damaged. See here, and here for examples of lipo combustion.I personally use, and recommend using a balance charger, and battery packs that have a balance connector. I would not use any batteries that did not have a balance connector. I use the IMAX B5 charger, which can balance charge up to a 5S pack, and will refuse to charge unless it determines that the battery is connected properly and is of the correct type.

I also use 20C rated packs with JST style connectors(see photo below).

I have found that HobbyCity.com has excellent prices and quick shipping(from Hong Kong).Also PLEASE READ the sticky post about Lithium Polymer batteries on rcgroups for much more in depth (and accurate?) information about the care and feeding of Lipo batteries.Happy flying!
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3D Robotics

FAQ: Confusing terms explained

Posted by Chris Anderson on July 21, 2008 at 10:30pm

This is a glossary of some of the terms you may read on DIY Drones. Please feel free to suggest others in the comments below!

  • 2.4 Ghz: The frequency used by digital (spread spectrum) radio communications in our applications, including 2.4Ghz RC, bluetooth and some video transmission equipment. This is a different band than the older 72 Mhz band that is used for analog RC communications. To avoid radio frequency conflict is it often a good idea to use 72 Mhz radio equipment when you are using 2.4 Ghz onboard video transmitters, or use 900 Mhz video when using 2.4 Ghz RC equipment.
  • AHRS: Attitude and Heading Reference System. See explanation here.
  • AMA: Academy of Model Aeronautics. The main US model aircraft association. Generally hostile to amateur UAVs, which are banned on AMA fields. But each AMA chapter and field may have slightly different policies, and it's possible to test airframes and some technology on AMA fields without violating the association's rules.
  • ArduCopter: Rotary-wing autopilot software for the APM and Pixhawk electronics
  • ArduPlane: Fixed-wing autopilot software for the APM and Pixhawk electronics.
  • ArduPilot: The overall autopilot project that ArduCopter, ArduPlane, and ArduRover live within
  • ArduRover: Ground and water autopilot software for the APM and Pixhawk electronics
  • Arduino: An open source embedded processor project. Includes a hardware standard originally based on the Atmel Atmega (and other 8-bit) microprocessor microcontroller and necessary supporting hardware, and a software programming environment based on the C-like Processing language. Official site is here.
  • BEC:  Battery Elimination Circuit. A voltage regulator found in ESCs (see below) and as a stand-alone product. Designed to provide constant 5v voltage for RC equipment, autopilots and other onboard electronics.
  • BASIC Stamp: A simple embedded processor controller and programming environment created and sold by Parallax. Often used to teach basic embedded computing and the basis of our autopilot tutorial project. Parallax also makes the very capable Propeller chip.
  • Bluetooth: A wireless technology standard for exchanging data over short distances (using UHF radio waves in the ISM band from 2.4 to 2.485 GHz) from fixed and mobile devices, and building Personal AreaNetworks (PANs). Originally conceived as a wireless alternative to RS-232 data cables. It can connect several concurrent devices.
  • Bootloader:  Special code stored in non-volatile memory in a microprocessor that can interface with a PC to download a user's program.
  • COA:  Certificate of Authorization. A FAA approval for a UAV flight. See this for more.
  • Eagle file:  The schematic and PCB design files (and related files that tell PCB fabricators how to create the boards) generated by the free Cadsoft Eagle program. This is the most common standard used in the open source hardware world, although, ironically, it's not open source software itself. Needless to say, this is not optimal, and the Eagle software is clumsy and hard to learn. One hopes that an open source alternative will someday emerge.
  • DCM:  Direction Cosine Matrix. A algorithm that is a less processing intensive equivalent of the Kalman Filter. See this for more.
  • DSM / DSM2 / DSMX: Spektrum, an RC equipment maker, refers to their proprietary technology as "Digital Spectrum Modulation." Each transmitter has a globally unique identifier (GUID), to which receivers can be bound, ensuring that no transmitter will interfere with other nearby Spektrum DSM systems. DSM uses Direct-Sequence Spread Spectrum (DSSS) technology.
  • DSSS: Direct-Sequence Spread Spectrum is a modulation technique. As with other spread spectrum technologies, the transmitted signal takes up more bandwidth than the information signal that modulates the carrier or broadcast frequency. The name 'spread spectrum' comes from the fact that the carrier signals occur over the full bandwidth (spectrum) of a device's transmitting frequency..
  • EEPROM:  Electonically Erasable Programmable Read Only Memory. A type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g.,static calibration/reference tables.  Unlike bytes in most other kinds of non-volatile memory, individual bytes in a traditional EEPROM can be independently read, erased, and re-written.
  • ESC:  Electronic Speed Control. Device to control the motor in an electric aircraft. Serves as the connection between the main battery and the RC receiver. Usually includes a BEC, or Battery Elimination Circuit (BEC), which provides power for the RC system and other onboard electronics, such as an autopilot.
  • FHSS  Frequency-Hopping Spread Spectrum is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver.advantages over a fixed-frequency transmission: Advantages: 1. Spread-spectrum signals are highly resistant to narrowband interference. The process of re-collecting a spread signal spreads out the interfering signal, causing it to recede into the background. 2. Spread-spectrum signals are difficult to intercept. A spread-spectrum signal may simply appear as an increase in the background noise to a narrowband receiver. An eavesdropper may have difficulty intercepting a transmission in real time if the pseudorandom sequence is not known. 3. Spread-spectrum transmissions can share a frequency band with many types of conventional transmissions with minimal interference. The spread-spectrum signals add minimal noise to the narrow-frequency communications, and vice versa. As a result,bandwidth can be used more efficiently.
  • FPV: First-Person View. A technique that uses an onboard video camera and wireless connection to the ground allow a pilot on the ground with video goggles to fly with a cockpit view.
  • FTDI: Future Technology Devices International, which is the name of the company that makes the chips. A standard to convert USB to serial communications. Available as a chip for boards that have a USB connector, or in a cable to connected to breakout pins. 
  • GCS: Ground Control Station. Software running on a computer on the ground that receives telemetry information from an airborne UAV and displays its progress and status, often including video and other sensor data. Can also be used to transmit in-flight commands to the UAV.
  • GIT: A version control system for software developers. The DIY Drones team use a Git-based service called GitHub.
  • Hardware-in-the-loop simulation: Doing a simulation where software running on another computer generates data that simulates the data that would be coming from an autopilot'’s sensors. The autopilot is running and doesn't "know" that the data is simulated, so it responds just as it would to real sensor data. Hardware-in-the-loop uses the physical autopilot hardware connected to a simulator, as opposed to simulating the autopilot in software, too.
  • I2C: Inter-Integrated Circuit. A serial bus that allows multiple low speed peripherals, such as sensors, to be connected to a microprocessor. See this for more.
  • IDE: An integrated Integrated development Development Environment, such as the Arduino editor/downloader/serial monitor software. Often includes a debugger.
  • IMU: An inertial Inertial measurement Measurement Unit. Usually has at least three accelerometers (measuring the gravity vector in the x, ,y and z dimensions) and two gyros (measuring rotation around the tilt and pitch axis). Neither are sufficient by themselves, since accelerometers are thrown off by movement (ie, they are "“noisy"” over short periods of time), while gyros drift over time. The data from both types of sensors must be combined in software to determine true aircraft attitude and movement. One technique for doing this is the Kalman filter (see below).
  • Inner loop/Outer loop: Usually used to refer to the stabilization and navigation functions of an autopilot. The stabilization function must run in real-time and as often as 100 times a second ("inner loop”), while the navigation function can run as infrequently as once per second and can tolerate delays and interruptions ("outer loop”).
  • INS: Inertial Navigation System. A way to calculate position based on an initial GPS reading followed by readings from motion and speed sensors. Useful when GPS is not available or has temporarily lost its signal.
  • ICSP: In Circuit Serial Progammer. A way to load code to a microprocessormicrocontoller. Usually seen as a six-pin (two rows of three) connector on a PCB. To use this, you need a programmer, such as this one, that uses the SPI (Serial Peripheral Interface) standard.
  • Kalman Filter: A relatively complicated algorithm that, in our applications, is primarily used to combine accelerometer and gyro data to provide an accurate description of aircraft attitude and movement in real time. See this for more.
  • LOS: Line of Sight. Refers to a FAA requirement that UAVs stay within a pilot's direct visual control if they are flying under the recreational exemption to COA approval.
  • LiPo:  Lithium Polymer battery, aka LiPoly. Varients include Lithium Ion (Li-Ion) battery. This battery chemistry offers more power and lighter weight than NiMh and NiCad batteries.
  • MAV: Micro Air Vehicle. A small UAV. More here.
  • MAVLink: The Micro Air Vehicle communications Link protocol used by the ArduCopter and ArduPlane line of autopilots. See this for more info on MAVLink.
  • Microprocessor: A microprocessor incorporates the functions of a computer's central processing unit (CPU) on a single integrated circuit or at most, a few integrated circuits (system clock, memory, peripheral device drivers).
  • Microcontroller: A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form flash or EEPROM is included on the chip, as well as a typically small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.
  • NMEA:  National Marine Electronics Association standard for GPS information. When we refer to "NMEA sentences", we're talking about ASCII strings from a GPS module that look like this:        
  • $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47
  • OSD: On-screen Screen Display. A way to integrate data (often telemetry information) into the real-time video stream the aircraft is sending to the ground.
  • PCB: Printed Circuit Board. In our use, a specialized board designed and "fabricated" for a dedicated purpose, as opposed to a breadboard or prototype board, which can be used and resused re-used for many projects.
  • PCM: Pulse Coded Modulation. A method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, Compact Discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled regularly at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps. Primarily useful for optical communications systems, where there tends to be little or no multipath interference
  • PIC: Pilot In Command. Refers to a FAA requirement that UAVs stay under a pilot's direct control if they are flying under the recreational exemption to COA approval. See Line of Sight above.
  • PID:  Proportional/Integral/Deriviative control method. A machine control algorithm that allows for more accurate sensor-motion control loops and less over-control. See this for more.
  • Pixhawk: The next-gen 32-bit autopilot, which succeeded APM. A collaboration between 3D Robotics and the PX4 team at ETH, the technical university in Zurich
  • POI: Point of Of Interest, also known as Region of Interest. Designates a spot that a UAV should keep a camera pointed towards.
  • PPM: Pulse Position Modulation. Signal modulation in which a set number of message bits are encoded by transmitting a single pulse in one of possible 2(number if message bits) time-shifts.
  • PWM: Pulse Width Modulation. The square-wave signals used in RC control to drive servos and speed controllers.
  • ROI: Region of Interest. Also known as Point of Interest (see above)
  • RTL: Return To Launch. Return the aircraft to the "home" position where it took off.
  • Shield: a specialized board that fits on top of an Arduino to add a specific function, such as wireless data or GPS
  • SiRF III: The SiRF is a technology company that has developed a standard used by most modern GPS modules. Includes SiRF III binary mode, which is an alternative to the ASCII-based NMEA standard described above.
  • Sketch: The program files, drivers and other code generated by the Arduinio IDE for a single project.
  • SVN: Short for the Subversion Version-control Number repository used by the DIY Drones (in the past) and other teams for source code.
  • Thermopile: An infrared detector. Often used in pairs in UAVs to measure tilt and pitch by looking at differences in the infrared signature of the horizon fore and aft and on both sides. This is based on the fact that there is always an infrared gradient between earth and sky, and that you can keep a plane flying level by ensuring that the readings are the same from both sensors in each pair, each looking in opposite directions.
  • UAV: Unmanned Aerial Vehicle. In the military, these are increasingly called Unmanned Aerial Systems (UAS), to reflect that the aircraft is just part of a complex system in the air and on the ground. Ground-based autonomous robots are called Unmanned Ground Vehicles (UGVs) and robot submersibles are called Autonomous Underwater Vehicles (AUVs). Robot boats are called Unmanned Surface Vehicles (USVs).
  • WAAS: Wide Area Augmentation System. A system of satellites and ground stations that provide GPS signal corrections, giving up to five times better position accuracy than uncorrected GPS. See this for more.
  • ZigBee (related: Xbee): A wireless communications standard, which has longer range than bluetooth but lower power consumption than WiFi.
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3D Robotics

Video of the BlimpDuino with vectoring thrusters

Posted by Chris Anderson on July 20, 2008 at 6:30pm

Switching BlimpDuino from modded toy blimps to a custom vectoring thruster platform was the best move we've made so far. Not only does it save a lot of money and fuss, but the vectoring thrusters give us much better control, including total command over the vertical dimension, which had plagued us before when we were using static thrusters. Right now we're testing it in RC mode to understand the flight dynamics better, but the same processor board can fly autonomously. Here's a video of it in flight, showing both turning (with differential thrusters) and altitude control (with vectoring); You might notice that it looks like I've got a breadboard with a tangle of wires controlling the blimp. That's because I do. I'm having trouble debugging the latest BlimpDuino board (the one with built-in RC mode), so I've replicated it on a small breadboard (using every single available row!). It's using this code. Here's what it looks like up close (and yes, those are Lego gears and shafts. Why use anything else?) :

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3D Robotics

DIY Drones on the Ning home page!

Posted by Chris Anderson on July 18, 2008 at 7:30am

Very cool! We're now a featured network on the home page of Ning, which is the social network service that this site is based on. They told me it was due to our "strong organic growth", which is due to all of you! We now average around 1,500 unique visitors and around 6,000 page views a day, and the growth is accelerating. By the end of today, we should break 1,300 members.
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3D Robotics

Wall Street Journal: Unmanned Aircraft Face Hurdles

Posted by Chris Anderson on July 16, 2008 at 10:14pm
From today's WSJ: Unmanned Aircraft Face Hurdles By ANDY PASZTOR July 17, 2008 FARNBOROUGH, England -- Unmanned aircraft are rapidly becoming mainstays of military and border-security operations worldwide. But significant commercial uses for the planes aren't expected to emerge for at least another decade because of regulatory and technical challenges, industry and government officials said at the international air show here. Between now and 2017, worldwide demand for unmanned aircraft, their payloads and related ground control systems is projected to top $17 billion, according to Forecast International, a Newton, Conn., consulting firm. But only about $100 million of that demand is expected to involve commercial applications. There has been sharp growth in the number of so-called Unmanned Aerial Vehicles used by the U.S. government in recent years for tasks ranging from battlefield surveillance in the Middle East to tracking wildfires in Western states. On an average day, some 30 unmanned Pentagon aircraft are in the skies over Iraq and Afghanistan. More than half of the 93 planes the U.S. Air Force envisions buying by late 2009 are UAVs, designed to be flown remotely by pilots on the ground. European governments also are showing greater interest. Aerospace companies are talking to the British government about possibly using unmanned aircraft to supplement conventional helicopters in providing security and monitoring car traffic at the 2012 summer Olympics in London. By then, according to Mark Kane, who heads the UAV business at BAE Systems PLC, the market for governmental uses of such aircraft could climb to as much as $10 billion annually, not counting the U.S. It has been widely assumed that there was considerable pent-up demand and momentum for commercial applications. But officials here indicate that may be wishful thinking. Regulatory hurdles, combined with technical and business challenges, are likely to block widespread commercial UAV operations on both sides of the Atlantic for a long time. "I don't foresee any certification in commercial airspace until 2020" or later, said Francois Quentin, senior vice president of the aerospace division of Thales Group SA. Earlier this summer, Federal Aviation Administration officials told a U.S.-European industry conference that preliminary proposals spelling out how UAVs can be widely integrated into the U.S. airspace were at least seven years away, with final regulatory approval unlikely before the end of the next decade. Kevin Brown, who runs Boeing Co.'s air-traffic control unit, said that figuring out how unmanned aircraft can sense and avoid other aircraft -- taking evasive maneuvers if necessary -- "is one of the hardest corners" of airborne-traffic management. In light of such complications, he said, "commercial applications are much further down the road." Nor are potential operators and customers beating down the regulators' doors to speed up their deliberations. What specific interest has surfaced primarily focuses on smaller and simpler UAVs. "Most of the applications we see are below" 300 pounds, according to Yves Morier, a senior European safety official. General Atomics Aeronautical Systems, which has its Predator aircraft deployed by the U.S. military in the Middle East, has looked at selling other UAVs to mining companies looking to use high-tech sensors for prospecting, or to monitor oil pipelines. But customers are scarce because "they're not ready for it," according to Thomas Cassidy Jr., president of a unit. Other advocates of unmanned aircraft also see a long uphill climb to commercial acceptability. "There are safety elements that need to be proven and policy decisions that must come before" UAVs become commonplace, according to Judy Marks, the head of Lockheed Martin Corp.'s air-traffic control unit. Safety requirements are lower for military and governmental versions, because they typically operate in segregated airspace and don't have to worry about potential collisions with airliners or general-aviation aircraft. For military applications, Boeing, United Technologies Corp. and BAE Systems are looking at developing completely autonomous UAVs, intended to fly or hover without any pilot input.
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3D Robotics

Warning: bad experience with UNAV

Posted by Chris Anderson on July 16, 2008 at 9:18pm
I've had mixed experiences with UNAV (maker of the Pico Pilot) in the past. I like their autopilot hardware, but the software is terrible and it all feels a bit dated and old-school. Based on some early looks I think Dean Goedde's AttoPilot is going to blow the Pico Pilot away (a proper review will be coming as soon as I get my hands on the hardware). But I wanted to be fair to UNAV, so I offered to review their new PicoPilot groundstation sofware, despite its high price ($100). UNAV's Dave Perry sent a disk and then the trouble started. Basically, it's the most amateurish software that I've ever seen offered for sale. It only works on Serial Port 1, which as everyone who has bought a computer in the last decade knows, is no longer the default serial port in the USB era, so you have to go into the windows device manager to remap the serial ports. All sorts of Windows error message pop up, such as "array out of bounds", of the sort I haven't seen since high school programming class. Worst of all, it doesn't do what it says it can do, which is to let you use a point-and-click interface to enter new waypoint data. The manual describes buttons and options that aren't in the software, and the UI is clumsy beyond belief. It may work as a groundstation, displaying aircraft position in real time (I didn't test that), but it doesn't work for data entry, which what I think most people would want it for initially. I could go on for paragraphs... So I wrote Dave with a list of bug reports, hoping that he'd thank me for my time in helping improve the software and offer to send me a new version once it was done. Sadly, that wasn't the case. Here's what he wrote: "I have no doubt that you've had problems with your PICO-GS. But since the program works fine on all our systems and our beta testers didn't report any significant issues and now several customers are successfully using it, I can only conclude that you are suffering from "operator error". Did you spend any time reading the manual ? From your descriptions, I'd take a wild guess and bet you didn't set your windows display to 1024x768 ( as called for in the manual ). If you don't have the time or patience to read the manual and follow the instructions, then I'd agree it would be a waste of time for you to continue with a review." Wow. "Operator error", as you all know, is the insulting term that bad programmers use to "blame the victim". It's a really crappy way to treat customers or, for that matter, reviewers. And when was the last time that you used software that required you to manually change your display resolution? 1997? Note no response to any of the bug reports, and a total refusal to acknowledge that the software simply doesn't work. Anyway, I've had it with them. I no longer recommend the PicoPilot, and I'll be switching our own UAVs to AttoPilots (which will be cheaper and better) as soon as they're out in a month or two.
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new plan

Posted by Aaron Weinstein on July 16, 2008 at 8:30pm
after much thought, i'm copping out of creating a UAV with video tracking.now the plan is to mount a decent video camera in a controlled environment in order to track infrared signals.blimps will have IR emitters on top, emitting some sort of modulated signal. with some fourier transform and the computing power of my mac, i can then locate and identify a given number of blimps in view.i'm trying to identify true (x,y,z) position of each blimp. i'm thinking of using some sort of pattern recognition (with led's set up in a simple pattern with set dimensions on top of each blimp) or i may just cheat and stick an ultrasound sensor on the bottom of each blimp. this would not be that good since any ground interruptions, like people, will greatly mess with the data. theres a bit to be ironed out of this scheme.anyway, the idea is that the blimps will be cheap (fast and out of control) and the computer is the brains, telling each blimp what to do. this way, i can get the computing power behind the video tracking. as of now i'm thinking of using JMyron in processing, since its easy to use, should be suitable, and i don't know Max/Jitter. I fear not being able to get enough data to have accurate fourier transforms (leakage, aliasing...?). the max fps of jmyron has me on edge.communication between comp. and arduino will use Xbee.been thinking of choreographing movement of blimps in a number of ways. ie: calculate thrust vector based off (x,y,z) and then blimps react accordingly. just a thought. could use some nice E&M potential fields as models.this is all one big changing thought. i just like the idea since it incorporates quite a bit and will provide a lot of new ideas to learn.
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3D Robotics

Lunch with Arduino co-founder Massimo Banzi

Posted by Chris Anderson on July 14, 2008 at 10:35pm

Massimo Banzi, the co-founder of the Arduino project, was in San Francisco today after spending the weekend at FOO Camp, and he dropped by for lunch with me at Wired. As you know we're huge Arduino fans, so this was a rare treat to learn more about how the project works and where it's going. We, along with Alexandra Deschamps-Sonsino, his business manager at his IT consultancy, tinker.it, happily chatted for a couple hours. Here, from memory, are a few of the tidbits I gleaned.
  • The Arduino roadmap includes new boards with speciality functions, including GPS, ethernet, ZigBee wireless, and cellular wireless.
  • The next generation of Arduino core boards will include Atmel's AtMega line with 64 I/O pins and 256k of memory.
  • After that, the project will move to Atmel's 32-bit line of chips.
  • People are considering implementing a proper debugger on the current Arduino platform, which would be great
  • Arduino could be ported to the ARM chips pretty easily, although there are no plans to do so at the moment
  • The project pays its bills by charging a license fee for officially certified third-party Arduino boards, such as the Arduino Nano
  • People think Arduino was named after a 15th century Italian king. It's actually named after the pub where the founders first started planning the project.
  • Projects such as our own ArduPilot and BlimpDuino, which use derivatives of the Arduino name, are generally fine, but should be sold as "Arduino compatible" rather than called Arduino boards.
  • Massimo and I talked a lot about what the breakout product would be for open source hardware in general and the Arduino project specifically. Odds are that it's no one product, but instead speciality products in different industrial verticals. But we agreed the most fertile ground for open source hardware is in the emerging GPS+wireless space: location-aware, net-connected sensing devices, or what Bruce Sterling calls "spimes" (a neologism combining "space" and "time").
  • Finally, he left me with a gift: one of the last remaining blank boards from the first version of Arduino, back in 2005. Only a few hundred were made. Here's a picture:

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3D Robotics

Is this for real?

Posted by Chris Anderson on July 14, 2008 at 9:30pm

Spotted in the current issue of Unmanned Systems, the AUVSI magazine: an ad for a sniper rifle/quadcopter UAV (shown above). Absurdly, it says you can take off the rotors and camera and also use the fuselage as an assault rifle! If this were the April edition, I'd think it was an April Fool's joke. The ad is full of typos and the company, AUS International, has a one-page website that looks like it was made in Microsoft Word in about ten minutes. There is no other information about them on the web, and whois says the company website was just registered in April of this year. Apparently they're based in Laredo TX, assuming that they're a real company at all.

What do you think? Is this for real?

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