Blogs

This is the result of my "indestructable" quadcopter design blog.

I dont know how well it crashes it yet but after 2 test flights, it flies very well! I need to do some PID tuning as the arms are quite short. They are 450 size heli tail booms that I cut for no other reason but to make the quad smaller and see what happens. Any PID tuning recommendations for shorter arms?

On to the nitty gritty. All the carbon fibre is 1mm thick. It was cut with a jigsaw using a fine metal blade and it works really well. The motor mounts are made of 4mm perspex and were cut using a hole saw. The landing gear is also 4mm perspex cut with a jigsaw and bent with a mini blow torch. I never realized how strong perspex actually is till I started messing around with offcuts! its unbreakable! under huge stress it just folds but never breaks in 2.

The total mass without battery is 630g and with 2200mAh battery 828g. I actually have no idea if this is light or heavy for a quad?

Price:

2x 100mm x 300mm x 1mm carbon fibre: $10.79ea

4 x 450 heli carbon fibre tail boom: $2.40ea

Screws, nuts, bolts: $8.00 nylon screws are quite pricey!

Perspex 300mm x 300mm x 4mm sheet: $10.00

Total: $50.00 Not Bad =)

The development team is always trying to find ways to improve our testing and the quality of our code. We've recently add a new automatic testing system that should help a lot with finding bugs and ensuring that the huge range of features that we have added (and plan to add!) to the code keep working.

If you have a look at http://autotest.diydrones.com you'll see the results from 'Tools/autotest', a test system that runs on every change to the ArduPilot and ArduCopter code. The test script currently checks the following:

• that both ArduPilot and ArduCopter build on the 1280 and 2560 based APM boards
• that both ArduPilot and ArduCopter can build with the 'desktop' build system
• that ArduCopter can fly in both manual and automatic (mission) mode
• that we can download the flight logs

It also keeps detailed logs, and produces a KML file which you can load in googleearth to look at how the flight went.

The flight itself is controlled using a python scripting system that flies ArduCopter using MAVLInk commands. Currently that script does the following:

• starts up the simulator at my local flying field
• arms the motors (using virtual transmitter sticks to control the rudder and throttle)
• switches the quadcopter to STABILIZE mode
• does a manual takeoff using throttle, until the altitude reaches 30 meters
• uses the rudder to turn the quad until it is facing north (it starts up facing west)
• uses the elevator and aileron sticks to manually fly a square circuit about 50m on a side
• switches to LOITER mode, and checks that it holds altitude for 10 seconds
• switches back to STABILIZE and decreases throttle, to bring the quad in for a gentle landing
• loads a 9 waypoint mission into EEPROM
• switches to AUTO mode and flies the mission, which involves a zig-zag route over the field
• the last mission step is a RTL, which brings the quad home
• then it switches to STABILIZE, brings the quad in for a landing, and disarms the motors

You can see a track of the test flight in the above googleearth screenshot.

Running these test steps every time we make a change to the code is already ensuring that a lot of our code works, but we have plans to greatly expand this test suite. What we'd like to do is have every ArduPlane and ArduCopter feature tested, with code that validates that it actually does the right thing. At the moment the test suite only has very rudimentary testing of whether the flight was actually correct, whereas we should be checking lots of parameters (roll, pitch, altitude, speed etc) throughout the flight.

The other obvious missing piece is ArduPlane testing. The test suite checks that ArduPlane builds, but doesn't yet check that it flies correctly. I hope to fix that this weekend, with ArduPlane flying some simple missions plus some 'manual' (ie. python scripted) flying. I'll probably do this by interfacing with FlightGear, but jsbsim linkage of even a new physics model is a possibility.

Under the covers

This new test system involves quite a few new bits of code, some of which we hope will be used for things other than automatic testing. The quadcopter simulator itself is a simple physics simulator written in python, which Michael has since translated into C# for use in the planner (thats how you can fly quadcopter HIL in the planner now). The communication between the various pieces uses pymavlink, a MAVLink implementation in python. That uses a bunch of helper scripts that make it fairly easy to script a ArduPilot vehicle. I'm hoping this system will be used for scripting real copters and planes in the future, along the lines of the acrobatic scripting system we discussed earlier in the year.

The other big part of this autotest system is the 'desktop' (also known as SIL for "software in the loop") build of ArduPlane and ArduCopter. This builds the code using a normal C++ compiler, and creates executables which run directly on your desktop computer, rather than on an APM board. The advantage of this is that we can use all the debug tools (such as gdb and valgrind) which are normally used for C++ development, but also it runs much faster and doesn't rely on hardware being plugged in. We've already taken advantage of the ability to run ArduCopter under valgrind to find some bugs, and it really increases our confidence in the code to be able to run that sort of sophisticated memory checking on every commit.

If you want to have a look at autotest, then start by grabbing the latest APM code and having a look in Tools/autotest. You might like to start by looking at arducopter.py and seeing how it controls the quad. We're hoping that we will get contributions of new tests. We also plan on putting up a wiki page describing how you can run the autotest system on your own computers (right now it only runs on Linux and MacOS, although Micheal has had some limited success on Windows using cygwin).

How you can help

The autotest system is already quite useful and it has already helped us find some subtle bugs in the QuadCopter code, but we'd love to expand it to cover more aircraft and features. Here are a few things that it would be great to get contributions on if someone has the time:

• we need physics simulations for more multi-copter frame types (start with quadcopter.py, and create ones for hexa, octa etc)
• I'd like to produce a nice picture of the flight path from a KML file using a script, so devs don't have to load googleearth to quickly check it looks OK
• we need some interesting test missions to look at. I hope to support loading missions in planner format soon to make this easier
• we need python code to more carefully check the flight is OK. It may be easier to wait on this until we develop some better helper functions, but if you are a python coder then feel free to jump in now

Hopefully this will be the beginning of a much more rigorous testing effort for ArduPilot. We'll post more information as the system develops!

Right now I'm far away from home, but I've found some extra time to work on my code for APM. But how am I going to test it without APM? Here is the video which shows a successful run of modified APM code on virtual APM =)

"\n" is not working good on this emulator.

Here is what you need:

Arduino IDE  direct link

Proteus (I'm using v7.7 sp2)  Demo version (according to demo limitations it cannot save or modify any MCU simulations, but you won't need it - you can use mine in read-only way, no problems with changing firmware) UPDATE: Unfortunately, there is no way to run my simulation file unless you have full (paid) version of Proteus.

APM firmware source code v2.24 (use newest if available)

and my Proteus simulation file attached (or you can do you own - it is really simple) ardupilot_sim.rar

UPDATE2: It is also possible to use AVR Simulator from AVR studio with HAPSIM plugin to get it running, but on my netbook it is sooo slow - so I couldn't make the video. 

I hope it helps.

Dear Friends,

in the last Months FoxTeam are working to develop some new exciting updates

We're working on Hardware:

• VR Brain MP32V3F1-IMU
• VR Brain MP32V3F4-IMU
• VR Distribution Board.
• VR Telemetry Board.

We implement two kind of ide for develop our project :

The VR IDE use:

• Standard Processing IDE same of Arduino.
• Complete integrated Eclipse IDE for editing , building and debug project (better for professional development)
• We are using OpenOCD Jtag Debugger for realtime inline debugging.

The Library :

• FoxTeam port and support Maple Library on all our platform.
• We port all standard APM library developed by DEVTEAM to MP32V3FX .

The Operating Systems :

We port on our platform different kind of Operating systems :

• FreeRtos
• ChibiOS

Firmware :

We porting on Multipilot32 the last revision of Arducopter 2.0.49 -50 firmware we try to mantain similar architecture of original Jason development but put inside same upgrade that is possible using the power of our platform.

Is available also professional support for develop custom application for different kind of application also for professional application .

After one year of experience on Arm Platform we are ready to present the new platform that will be available in the next months and in the new year.

News about Hardware :

Is available the new revision of Board the Multipilot32V3FX

It's will be available in different configuration :

MP32V3F1 - IMU

use the same micro of MP32V1 but have some upgrade for improve the quality of pcb and some news about the onboard peripherals :

• support SD using SDIO bus that is more fast of standard SPI port.
• We add also the support of USB as serial debug port.

The micro that we use is STM32F103 .

512 kbyte Flash and 64 Kbyte ram 72 Mhz cpu speed.

12 bit analog input.

16 bit PWM output.

The platform is available to end user.

MP32V3F4 - IMU

is the first low cost autopilot platform board that support powerfull STM32F4 Arm Cortex M4 micro .

1024 kbyte Flash and

196 Kbyte ram.

168 Mhz cpu speed.

USB Host OTG

Standard Video Input interface.

Integrate FPU (Floating Point Unit) for example the SQR function on STM103 is doing in 1200 cycles on STM32F4 it doing in 196 cycle. 10x fast

Integrate DSP hardware unit good for hardware matrix transformation , DCT and IDCT functionality.

12 bit analog input.

16 bit PWM output.

More info about the architecture of STM32F4 : http://www.emcu.it/STM32F4xx/STM32F4xx.html

check the official ST video presentation for more info about the new micro. I'm very happy to choose 1 years ago to invest on ST micro instead of SAM3U Atmel micro . ST doing us a big opportunity with this new microcontroller.

The platform is yet available for developer for more info about it contact me at lasernav@gmail.com

Is available the IMU revision of MP32V3FX .

We integrate on same board the MPU6000 that use SPI bus and DMA to transfer data between the micro and imu sensor.

in this sensor is available:

• Tri-Axis angular rate sensor (gyro) with a sensitivity up to 131 LSBs/dps and a full-scale range of ±250, ±500, ±1000, and ±2000dps
• Tri-Axis accelerometer with a programmable full scale range of ±2g, ±4g, ±8g and ±16g
• Digital Motion Processing™ (DMP™) engine offloads complex MotionFusion, sensor timing synchronization and gesture detection

Check this link for more info about the product :

http://invensense.com/mems/gyro/mpu6000.html

With this kind of architecture is posible to fly without any other kind of board. Is a good and powerfull RTF board.

To be continued ... :)

Original Post : http://www.virtualrobotix.com/profiles/blogs/project-update-mp32v3f4-arm-cortex-m4-available-fpu-and-dsp-on-bo

Hi guys! I'm giving you a preview of an upcoming product from the DIY Drones store, the MinimOSD, a minimal Arduino-based on-screen display board. It's tailored for use with ArduPilot Mega and the MAVlink protocol, and designed to be as compact as possible.

It's main components are an ATmega328P 8 bit microcontroller with an Arduino bootloader, and a MAX7456 monochrome on-screen display. Programming is done through an FTDI-compatible 6-pin header.

It features two independent power and ground sections to isolate the OSD's analog stage: a +5V section for the ATmega and the OSD's digital stage, powered through the FTDI cable or other +5V source; and a regulated +5V section for the OSD's analog stage, powered through the video in/out header and capable of handling up to +12V input. Solder jumpers are available to combine the two power and ground sections if desired.

Spec lists are the best, so here's one!

• ATmega328P with Arduino bootloader
• MAX7456 monochrome on-screen display
• FTDI cable compatible pinout
• Standard 6-pin ISP header
• Two independent power sections with an LED indicator on each
• Solder jumpers for combining the power sections
• +5V 500mA regulator for up to +12V supply input
• Solder jumper for PAL video option
• Exposed test points for HSYNC and LOS
• Dimensions: 0.7"W x 1.7"L (2.4" w/ pins as shown) x 0.3"H

The production version won't be green, and we're not too fond of blue anymore, so expect something different on future products ;)

(And yes, I know I missed a decoupling cap on the board in the photo. Sorry Chris!)

Expected release date is within 2-3 weeks, price is TBD. Watch this space! UPDATE: Price will be $89.99 USD.

Here's a video I made for our rc club's website.  Almost all aireal video is shot with my ArduCopter hexacopter and a cheap 50 euro Kodak ZX-1 cam.  Firmware versions flown are 2.0.46 to 49.

For shooting the planes in flight I used a 7" carDVD LCD monitor bolted to my transmitter.

The intention was to show the website visitors what can be expected at our club and to give them a taste of the nice atmosphere and us just having fun.  Hope the message comes across!

Starting next year (2012) MyGeekShow will be getting into FPV / technology aided flight (autopilot, flight stabilization, etc). However, we’ll need your help selecting and installing the right equipment, which is where you come in!

What are we doing?
We’re putting together a small team of people we can go to for help/advice as we start exploring this “advanced” field of our hobby. As we learn from you and from firsthand experience we’ll publish videos each week showing how-to’s, product reviews, episodes, etc. showing others what we’re learning (see MyGeekShow on YouTube to see what’s been posted over the last year).

What’s in it for you?
-You’ll get to work and network with other experts in this field who you can teach and learn from.
-We’ll pass on the knowledge you give by posting videos on YouTube, sharing your knowledge with thousands of viewers.
-Assist in our goal of flying an RC Airplane 3,000+ miles to cross the U.S.
-Opportunity to participate in future MyGeekShow projects.

What is required to be on the team?
-At least six months to one year of experience in some kind of FPV or “technology aided flight” (example: autopilot, flight stabilization, data logging, etc).
-Willing to participate in the team for 6-12 months.
-Contribute on a weekly basis to an online discussion group.
-Show respect to other team members.

How do I join?
-Email trent@mygeekshow.com and let us know you’re interested and what kind of RC experience you have.

What is MyGeekShow?
MyGeekShow is a YouTube channel focused on the exploration of the RC airplane world with a 5 year mission that cumulates in a weeklong 3,000 mile flight to cross the United States. Learn more by going to www.MyGeekShow.com or visiting our YouTube channel: www.youtube.com/MyGeekShowdotcom

Hope to hear from you!

-Trent

From IEEE Spectrum:

The International Micro Aerial Vehicle Conference/Competition took place back in September, and unfortunately, we couldn't make it because we weren't sure how to pronounce the name of the place in which it was being held: 't Harde, in the Netherlands.

While IMAV had plenty of papers and talks and stuff, the most exciting bits were the indoor and outdoor MAV competitions. Inside, little autonomous flying robots had to identify and collect objects from within a structure, while outside, teams of MAVs had to cooperate to locate and observe groups of people, drop objects in specific locations, and even pop balloons. For both competitions, points were awarded for completing more difficult and complicated tasks and for increased autonomy.

The winner of the outdoor competition was DLR; they've got their own video which you can check out here.

One of the robots in that video in particular caught my eye:

 

This is called MAVion, and it's a fixed-wing tilt body aircraft thing from the Institut Supérieur de l’Aéronautique et de l’Espace in France. Those big wheels aren't just for take-off and landing; MAVion uses them in concert with its rotors to drive up walls and along ceilings, which is nice since you can use walls to your advantage in confined spaces instead of treating them as obstacles.

For more info on all of the participating teams, you can page through this PDF which has specs, pics, and descriptions for most of the bots involved.

 

It was great to see in that PDF that some of the contest entrants were using ArduPilot, including this cool VTOL design:

From Sparkfun, a $100 prize if you can decrypt the serial output from a commercial laser tape measure so it can be possibly hacked into a sensor useful for robots: 

"This tutorial, "Laser Tape Measure Hacking," comes from SparkFun CEO Nate Seidle (aka, El Queso Grande). Nate was intrigued by the idea that if he could hack a laser tape measure, it could be used in autonomous vehicles, 3D scanning, or any number of other applications. So Nate set out to hack the device. Unfortunately, he wasn't able to wrangle the serial controls and hit a wall. That's where you come in."

 

i just found this while browsing the web and thought it looked cool and figured i would share with the group.

i have not seen this before, it is from 2009 according to the date on it, if anyone has seen it before or if it has been on DIY Drones before let me know.

anyway it looks real cool and i would love to fly it and after the guys that flew the big quad copter last month i thought this was a nice idea here is the link to the story. http://www.nextconceptcars.com/concept-cars/ktm-design-studies/#more-1970

I recently presented a brief overview of my current Arcticopter project and some of the underlying technology.  I added some notes and uploaded the slides here.  This slide got the most laughs, and there's a cautionary note at the end.

The FOX is really unflyable in RC mode when the motor is below 30% throttle, autopilot handles it much better.
I believe it could be the smallest _classic_ layout winged _outdoor_ UAV in the world, the reason is that small UAVs are typically flying wings in order to have larger wing chord what plays major role at low Reynolds numbers.
It is not fun to fly in manual mode because it stalls for any reason. But it can be done and all landings are a spectacular crash when plane bounces like a ball from any obstacle it finds, spiralling around Z axis.
It has surprisingly good 31min endurance and 50km/h cruise speed, what because of its size feels like it would be flying at 100km/h. It is so small you lose it from view if you turn in the wrong direction, I cannot tell its orientation from more than 250m away. From 400m it is a tiny dot that you lose forever if you blink. It is also inaudible from more than 150m away so flying it is a real thrill: 'is it still up there?'.

Yet another UAV on rudder only I have made, but there are others with full house mechanics. No, airspeed sensor is not necessary for this airframe but would make tuning so much easier. It would be also the first thing to break all the time, so I am using Pitot tube only on a few specific birds.

This plane is fully autonomous and can navigate waypoints even 20-25km away as endurance permits, RC controller is used for trimming, testing and backup control.

It is driven by FLEXIPILOT, developed by me in ancient times.
Not for sale, not a gift. But it works and scares the neighbours, 'because it can be done'.

Hello all, I have been a member of this community and active in the UAS industry for some time. I am currently teaching a 2 credit sophomore level mechanical engineering design class at a 4 year university where the students typically make devices to compete in the American Society of Mechanical Engineers (ASME) student competition. This year the competition is a relay race for vehicles with different energy sources. (http://www.asme.org/events/competitions/student-design-competition)

I am teaching the same class next semester, however the class/project will have a UAS twist to it. As much  as I would like to have each student team put together a fully autonomous APM based aircraft and fly it, it is simply not practical from a cost, liability, and course load/timeline perspective at the moment.

I think it would be practical to have the students use a cheap/simple RC quad control board (aka hobbking/kk quad control board) to design and construct a quadrotor to complete some sort of indoor mission. I was wondering if this creative community could help me think of a potential competition/task that falls within the following guidelines.

1. A significant component of the competition involves designing a novel mechanism to perform a task(s) such that it can be determined to what degree one team did better than another.

2. The task is relevant to actual missions quadrotors/small UAS would perform in the real world.

3. A person with minimal RC flying skills could complete the task.

I have some ideas but at this point I don't want to taint other's input. Thanks for any ideas/thoughts. I think this will be a great opportunity for students to get some exposure to the systems engineering that surrounds UAS and get them interested in this hobby/career path.

Two and half years ago, we started the T3 (Trust Time Trial) Contest here at DIY Drones. The idea was simple: give people a mission to accomplish, on their own field and on their own time. They would record the telemetry, and submit a KML file with the result (we "trust" that it hasn't been faked). We could then compare the result and decide who was the winner (fastest time, best pattern, etc), as if they had all been racing/competing head-to-head. 

Back then, it was an accomplishment just to complete an autonomous mission with a regular plane. But we've made a lot of progress since then, and that's now possible with a multicopter or traditional helicopter, too. So it's time to relaunch the T3 Competition. And we're going to do it by returning to the first mission ever: the Figure Eight, but this time expanded to include copters.

Figure Eight Mission Rules:

1. There are two categories: Fixed Wing and Rotary Wing (multicopters or traditional helis). 1st, 2nd and 3rd place awards will be given in both.
2. Must complete the pattern as shown above, totally autonomously (go into auto mode before waypoint 1 and exit after you hit waypoint 1 again). The four points are arranged in a square, with 200m on a side for fixed wing aircraft and 100m on a side for rotary wing aircraft (obviously the two diagonal paths are longer). Any aircraft/autopilot allowed. It doesn't matter how close to the waypoints you get, as long as you pass on the outside of them.
3. Altitude is not graded.
4. Fastest time in each category to hit all points and return to 1 wins (one lap). 
5. The Judge will be Gary Mortimer, as always!
6. Deadline is Sunday, Dec 11th, at midnight PST.
7. 1st Prize in each category is a $100 gift certificate to the DIY Drones store. 2nd and 3rd prizes are $25 each.

Entries should include these three things:

1. Total time, along with aircraft (and type: fixed or rotary wing) and autopilot used. A photo of the aircraft would be nice, too.
2. KML file of the run (an onboard video is also encouraged, but not required)
3. Screen capture of path exported to Google Earth or an equivalent, annotated with waypoints and where autonomy began and ended. Here's a sample from my first entry, way back then (original ArduPilot!):
   

In an attempt to make a flight plan that will make it over a mountain peak and land in a valley, I have defined the following plan to command Ardupilot to loiter to a certain high altitude, traverse to another waypoint, then loiter safely down to another low altitude:

xplane_high_alt.h

#define WP_RADIUS 30 // What is the minimum distance to reach a waypoint?
#define LOITER_RADIUS 60        // How close to Loiter?
#define HOLD_CURRENT_ALT 0      // 1 = hold the current altitude, 0 = use the defined altitude to for RTL
#define ALT_TO_HOLD 100float mission[][5] = {
{WAYPOINT,0,528,49.9630094,-119.378643},
{LOITER_TURNS,1,1500,49.963037,-119.3742228},
{CONDITION_CHANGE_ALT,0,1500,1000,0},
{DO_JUMP,7,0,49,0},
{LOITER_TIME,5,1500,49.963037,-119.3730211},
{DO_JUMP,2,0,100,0},{WAYPOINT,0,1500,49.9585921,-119.3729353},
{LOITER_TURNS,1,1500,49.9585921,-119.3743086},
{CONDITION_CHANGE_ALT,0,528,1000,0},
{DO_JUMP,13,0,49,0},
{LOITER_TIME,5,528,49.9585645,-119.3757248},
{DO_JUMP,8,0,49,0},
{WAYPOINT,0,528,49.9583989,-119.3808317},
{RETURN_TO_LAUNCH,0,528,49.9629542,-119.3808746},
};

The first part works (loiter to altitude) perfectly, but the problem is as soon it reaches the second part (waypoint #7) Ardupilot just returns to launch without descending at all, as if it thinks it has already descended and should continue on. 

Have I messed up the flight plan, or is this a bug by chance?



I started to work on my Bixler EPO 1400mm - (ARF) and this kit have some problems :)

The fuselage is glued, but very bad, I was able to pull it apart by hand :) That made it easier to remove the washers from the nose, ( it will have enough weight in the end :) )

and the horrible motor mount that was hot-glued to one side and at very strange angle :) And there is no way to change the motor if the plane is assembled :(

I wanted better motor mount :) And with the option to change the motor !!! So I made one :) 

Its only 13g.

The tube is glued in, motor and the mount plate slides in and locked by two screws.

now I can change the motor :)

Thanks.

ArduCopter GoPro 2-Axis Camera-mount

ArduCopter factory is  pleased to release first camera mount to famous ArduCopter frames. 

This camera-mount fits on all original ArduCopter Quads and Hexas made by jDrones. It has 2 controllable axis that is supported already on ArduCopter software. Miniature ball bearings on all hinge locations. Custom made aluminum nuts to ensure proper mounting of the parts. 2 adjustable push rods with all linkage balls and ball links.

With mount plates this camera mount can be fitted to all Tri, Quad, Hexa and other future frames. On request we can make plates even for other frames.

Material: Fiberglass

Weight: 88 gr (includes mount plate and 9g servos)

Servos: 9g-12g (not included)

Frames: Quad, Hexa

Deliveries for these mounts will start on end of 2nd week of November and it can be purchased first from jDrones directly and later on from all jDrones distributors around the world.

Store link: ArduCopter GoPro 2-Axis camera-mount

Don't forget to have correct mount plate to your frame.

Many will know of people who through illness or injury who used to fly etc... and no longer can, would like to be able to do so again (I am in the above). 

Our project (my wife is now my hands) is to use a head based sensor and the APM to achieve some form of control.  If there is anyone interested in this project and some genuine interest I'm sure my lovely wife will add to this blog.

To date we have built a stable quad with our own cnc cuttout components and Multiwii as the basic platform which will be moved to the APM once we have the headset (2 x accelerometers, 1 acting as a static reference for the dynamic accelerometer) finished and working as a PPM stream into the trainer port on our Hitec transmitter.

I know there are head trackers avaliable but these do not inject the full 5 channels we need.  We are currently trialing some arduino code by Ian Johnston for the full 6 channel injection. Photo below is in level flight hands off. As above any interest feel free to comment. (the camera must have been at the right shutter speed to show the props as stopped)

It's all about expectations, I suppose, but even knowing that I have to admit disappointment.  We just got back from a visit to the National Air and Space Museum on the mall in Washington DC.  If you have never been there, you really need to go.  This isn't about the museum in general--we have been there many times.  One reason I wanted to go this time was to see the UAV exhibit.  Other than one small display case with an RQ-14A Dragon Eye, what you see in the photo above is pretty much it.  In hindsight, I can't say what I expected other than "more."  More information, more artifacts (maybe a sensor pod or two), more history.  To add insult to my self-imposed injury (It's about expectations, remember?), the gallery beneath the hanging UAVs was closed--no chance of getting  photos from different angles.

So, what is the point of this post?  One, misery loves company, so please feel bad with me.  Two, if you happen to be planning a trip mainly to see this exhibit, you might want to hold off.

Here's a LINK that gives info on the UAVs in the exhibit.  My photos aren't all that great, but here are a few more: