Blogs

All Posts (14048)

Sort by

Micro Helicopter Hovering in Place Using Vision Sensing

Posted by Geoffrey L. Barrows on January 27, 2010 at 1:30pm

3689338769?profile=original


Find more videos like this on DIY Drones

Find more videos like this on DIY Drones
Some of you may have seen Centeye's old website showing our earlier work flying optical flow sensors on small RC-class aircraft. Much of this work was sponsored by DARPA and the U.S. Air Force. More recently we have been hacking an eFlite Blade mCX, a very stable small 7" contra-rotating coaxial helicopter.The helicopter is a basic mCX airframe, minus the front canopy, and with the out-of-box green receiver / controller board replaced with one of our own design. Our own board sports an Atmel AVR32 microcontroller and an AT86RF230 wireless chip as well as carbon resistor strips and transistor circuits to implement the swashplate servos and rotor speed controllers. We have also integrated into the board a 6DOF IMU using standard MEMS components.In front of our controller board is a sensor ring with eight custom designed vision sensors mounted on a flexible circuit board and a processor board having another AVR32. They are stacked vertically via 0.8mm board-to-board connectors- Thank You cell phone industry! The processor board operates the eight vision sensors (which form an nice parallel system), acquires the imagery, computes optical flow, and sends high level control signals to the controller board. The whole sensor ring, including processor, flexible ring, vision sensors, and optics together weigh about 3 grams.Using a variation of control algorithms developed by Sean Humbert's lab at the University of Maryland at College Park, we were able to have this helicopter "hover in place" for up to six minutes straight. We could even perturb the helicopter slightly by manually moving it, and it would attempt to return to its original position. We have been able to get this demonstration working in a variety of room sizes and illumination levels. For these experiments, we did not use the IMU- the helicopter held its position (including yaw angle) using purely visual information. The man in the videos above is Travis Young, who has been executing the control aspects of this project at Centeye.Just to make it clear- All sensing, processing, and control is being performed on the helicopter. There is no human in the loop in these videos.Centeye is participating in the NSF-funded Harvard RoboBees project, led by Harvard EECS professor Rob Wood. As part of this project, we will be building vision sensors weighing on the order of tens of milligrams. If all goes well, we should have our first prototype at this scale by this summer!The RoboBee project will also let us do something that I personally have been wanting to do for a long time- to develop a portfolio of purely consumer/academic/hobbyist vision sensors that I can get into the hands of people like the members of this community! I'll be starting a thread soon in the "Sensors and IMUs" forum where I'd enjoy discussing this with everyone.
Read more…

Project Andromeda

Posted by Nima Kayvan on January 26, 2010 at 4:19pm

I've put together a website for a project I've been working on for 2 years now and will hopefully enter it into the Australian Outback UAV Challenge if it's held in 2010. Just wanted to post the website here for those who are interested. I'll post here when I add new entries for the blog with an excerpt for those who wish to follow the progress.Website: http://www.projectandromeda.com.auBlog: http://www.projectandromeda.com.au/blog
Read more…
3D Robotics

My Wired cover story on the "New Industrial Revolution" (including DIY Drones)

Posted by Chris Anderson on January 26, 2010 at 10:00am

One of the ways I can reconcile the amount of time I spend with DIY Drones is to think of it as a grand experiment in open innovation, which I not only participate in but also observe. That, in turn, helps me do my day job (editor of Wired Magazine) better. So for those of you who suspected that this is all grist for my next book, you're probably right ;-) This week we published my cover story, "The New Industrial Revolution" [AKA "Atoms are the New Bits"], on the broad implication of the trend of the "democratization of the tools of production" in manufacturing, which is the combination of cheap and easy prototyping tools and global manufacturing supply chains now opening to individuals and small teams. And yes, DIY Drones comes up in the story. Here's that excerpt:

"Three years ago, out on a run, I started thinking about how cheap gyroscope sensors were getting. What could you do with them? For starters, I realized, you could turn a radio-controlled model airplane into an autonomous unmanned aerial vehicle, or drone. It turned out that there were plenty of commercial autopilot units you could buy, all based on this principle, but the more I looked into them, the worse they appeared. They were expensive ($800 to $5,000), hard to use, and proprietary. It was clear that this was a market desperate for competition and democratization — Moore’s law was at work, making all the components dirt cheap. The hardware for a good autopilot shouldn’t cost more than $300, even including a healthy profit. Everything else was intellectual property, and it seemed the time had come to open that up, trading high margins for open innovation. To pursue this project, I started DIY Drones, a community site, and found and began working with some kindred spirits, led by Jordi Muñoz, then a 21-year-old high school graduate from Mexico living in Riverside, California. Muñoz was self-taught — with world-class skills in embedded electronics and aeronautics. Jordi turned me on to Arduino, and together we designed an autonomous blimp controller and then an aircraft autopilot board. We designed the boards the way all electronics tinkerers do, with parts bought from online shops, wired together on prototyping breadboards. Once it worked on the breadboard, we laid out the schematic diagrams with CadSoft Eagle and started designing it as a custom printed circuit board (PCB). Each time we had a design that looked good onscreen, we’d upload it to a commercial PCB fab, and a couple of weeks later, samples would arrive at our door. We’d solder on the components, try them out, and then fix our errors and otherwise make improvements for the next version. Eventually, we had a design we were happy with. How to commercialize it? We could do it ourselves, getting our PCB fab house to solder on the components, too, but we thought it might be better to partner with a retailer. The one that seemed culturally matched was SparkFun, which designs, makes, and sells electronics for the growing open source hardware community. The SparkFun operation is in a newish two-story building in an office park outside Boulder, Colorado. The first floor is larger than three basketball courts, with racks of circuit boards waiting to be sold, packed, and shipped on one side and some machines attended by a few technicians on the other. The first two machines are pick-and-place robots, which are available used for less than $5,000. They position tiny electronic components in exactly the right spot on a PCB. Once each batch of boards is done, technicians place them on a conveyor belt that goes into another machine, which is basically just a heater. Called a reflow oven, it cements the parts into place, essentially accomplishing what a worker could do with a soldering iron but with unmatched precision and speed. The PCBs arrive from SparkFun’s partner firm in China, which makes millions of them using automated etching, drilling, and cutting machines. At volume, they cost a few cents each. That’s it. With these elements you can make the basics of everything from a cell phone to a robot (structural elements, such as the case, can be made in low volume with a CNC machine or injection-molded if you need to do it cheaper at higher volume). You can sell these components as kits or find some college students on craigslist to spend a weekend assembling them for you. (I conscript my kids to assemble our blimps. They rotate roles, coveting the quality assurance task where they check the others’ work.) SparkFun makes, stocks, and sells our autopilot and a few other products that we designed; we get to spend our time working on R&D and bear no inventory risk. Some products we wanted to make were too time-intensive for SparkFun, so we made them ourselves. Now, in a rented Los Angeles garage, we have our own mini SparkFun. Rather than a pick-and-place robot, we have a kid with sharp eyes and a steady hand, and for a reflow oven we use what is basically a modified toaster oven. We can do scores of boards per day this way; when demand outstrips production, we’ll upgrade to a small pick-and-place robot. Every day our Web site takes orders and prints out the shipping labels. Muñoz or one of his workers heat-seals the products in protective electrostatic bags and puts them in shipping envelopes. The retail day ends at 3:30 pm with a run to the post office and UPS to send everything off. In our first year, we’ll do about $250,000 in revenue, with demand rising fast and a lot of products in the pipeline. With luck, we’ll be a million-dollar business by the third year, which would put us solidly in the ranks of millions of similarly successful US companies. We are just a tiny gear in the economic engine driving the US — on the face of it, this doesn’t seem like a world- changing economic model. But the difference between this kind of small business and the dry cleaners and corner shops that make up the majority of micro-enterprise in the country is that we’re global and high tech. Two-thirds of our sales come from outside the US, and our products compete at the low end with defense contractors like Lockheed Martin and Boeing. Although we don’t employ many people or make much money, our basic model is to lower the cost of technology by a factor of 10 (mostly by not charging for intellectual property). The effect is felt primarily by consumers; when you take an order of magnitude out of pricing in any market, you can radically reshape it, bringing in more and different customers. Lowering costs is a way to democratize technology, too. Although it’s shrinking, America’s manufacturing economy is still the world’s largest. But China’s growing production sector is predicted to take the number one spot in 2015, according to IHS Global Insight, an economic-forecasting firm. Not all US manufacturing is shrinking, however — just the large part. A Pease Group survey of small manufacturers (less than $25 million in annual sales) shows that most expect to grow this year, many by double digits. Indeed, analysts expect almost all new manufacturing jobs in the US will come from small companies. Ones just like ours."
Read more…
Developer

New 3-Axis MagnetoMeter Available (HMC5843)

Posted by Jordi Muñoz on January 25, 2010 at 12:30pm
Yes you got me, i love to make boards. ;-)The new magnetometer is pretty flexible, it will let you (through a solder jumper) select 5V or 3.3V mode, it has a 3.3V voltage regulator and an I2C translator (translate the I2C signals to 3.3V to void damage to the unit), so you are free to use it with any microcontroller (normally you don't suppose to connect it to a micro-controller that uses 5V signals). In other words is the smallest, cheapest, 5V and 3.3V, 3-axis magnetometer on the market (yet).

Another feature is that you can remove the screw holes sides in order to keep the minimum size. If you don't care about the size but you care about holding it very well then just leave as is. My recommendation for ArduIMU+ and other projects is to place it as far as you can from the any magnetic interference, you can solder a long wire all way down to the magneto board, don't worry about the noise because the i2c protocol is digital (not analog) and also the "I2C translator" acts like as a signal booster. Do you want more?

For ArduIMU+ and future ArduPilotMega Shield owners the magneto board will be pin compatible, so you can just place it on top (as the upper picture indicates), without compromising the low profile of the board:

All this for just $49.90, the same price as the SparkFun board but with more feactures. Also it works under any circumstances, thanks to its bigger tantalum capacitor (33uF).You can get yours here:http://store.diydrones.com/ProductDetails.asp?ProductCode=BR-HMC5843-01If you mix it with the ArduIMU+ it will cost $25 more than the 9DoF Razor board, but just remember that ArduIMU+ runs at 16MHz, has GPS port and you can easily place the magnetometer away from the board in case you have noisy magnetic fields close to that board that normally don't affect the accelerometers and the gyros, also the 9DoF board has I2C accelerometer that i doubt is better than the analog one we have.The advantages of 9DoF Razor is that you have Lithium Battery port, ON&OFF switch, fixed mounting holes, is $25 cheaper and soon will support our DCM code. So is up to you! ;-)Thanks for all your support!
Read more…

10th birthday of GoRobotics.net

Posted by William Cox on January 25, 2010 at 9:08am

january-_contest1.png

So, I run a robotics blog at GoRobotics.net, and low-and-behold it's been 10 years since I started it! Yikes! Time flies (autonomously?). As a way to celebrate and say thanks to all the loyal readers and followers, I contacted several robot companies (Pololu, Trossen, Apress, and SuperDroid) and got them to donate some prizes. We got lots of cools things (with hopefully more to come), and I'll be giving them away on the site over the next few months leading up to the official birthday in April. You can enter the January giveaway here: http://www.gorobotics.net/the-news/january-giveaway-10-years-of-gorobotics/There's not any aerial-specific parts, but some of the prizes could be used on a Drone (a nice 6 servo controller from Pololu, for instance). Maybe I should see if Chris will donate a ArduPilot? :)Anyway, I'm pumped about the giveaways and excited for another 10 years of blogging! Let me know what you think.
Read more…
Moderator

2010 UKAP meet.

Posted by Gary Mortimer on January 25, 2010 at 8:15am
Planning has begun for the next Southern Counties Radio Controlled Aerial Photographers meet

ukap_ashorne_group_photo_small.jpg

That was last year, and heres a bit of David Hoggs video as well..

%3Cobject%20width="400"%20height="300"

UKAP/AV Meeting - 4th/5th July 2009 from David Hogg on Vimeo.

' />

Check out the following thread in RCG for this year.http://www.rcgroups.com/forums/showthread.php?t=1175889YellowPlane will be there with a couple of Atto flown wings and we will also have the Falcon 8 and a quad.Perhaps its just the place, even though date and time has not been sorted for a DIYdrones get together as well??Who knows, as regulations have changed so that fitting a camera makes your airframe a UAS in the UK we might manage the biggest get together of flying UAS the UK has seen. Won't be hard!Its an international meet, we had a Frenchman and somebody from Herefordshire, that's nearly Wales oh and of course Mike came down from Scotland, further than the Frenchman! He will be bringing the wine!Heres the place to look for images from last years event.http://www.rcgroups.com/forums/showthread.php?t=1075238Lots of fun, so sign up on the RCG thread if your interested. Don't tell them I sent you, I might be in trouble.G
Read more…

All in one UAV controller board

Posted by Radoslaw Kornicki on January 24, 2010 at 9:45am
Well, almost... few more things will be added in the next hardware version.This is a project that started about 3 years ago when I began building a P-47 rc airplane. Back then I decided that if it is worth doing it is also worth overdoing, so I began working on a small on board computer that would cycle the landing gear hatch doors when as it is being retracted. Since then plane never progressed forward but the simple on-board computer did.Here is what it looks like today:

and on the back:

What You can see there are:- LISY300AL with IDG500 gyros- MMA7260Q triple axis acceleration sensor- HMC6343 3 axis magnetic sensor / tilt compensated compass and additionla 3 axis acceleration sensor- SCP1000 pressure sensor - used for altitude estimate- FC30TR orientation sensor - used for calibration and in-flight attitude corrections- 4Hz 50 Channel GPS + Serantel antenna based on u-blox UBX-G5010 chip- microSD card for data logging- xBee for wireless uplink- 4 optically isolated PWM rc servo channels booth for input and output with ESD protection- SEPIC DC to DC converter - will sustain full board operation down to 1V left on the battery- high speed I2C communication expansion port- CAN communication port- all controlled from a dsPIC microAll of that on a credit card size board!Obvious things that are missing (will be added in next version):- airspeed sensor- landing gear retracts air tank pressure sensor- battery level and fuel level sensing capability (booth for electric and nitro planes)- few more PWM channels (with intended micro change, I should be able to go up to 12 pwm output channels and 6 in!)- floating point capable processor to speed up code executionCurrently the board was tested with slightly modified version of Ben Levitt's MatrixPilot code.In parallel some ground work was laid down to create more sophisticated sensor fusion algorithms through an extended Kahlman filter, so far basic functionality gives pitch and roll readings (based on accelerometers and gyros) with yaw pulled from both the compass and gps. If time allows, future version will "fuse" all of the available sensors creating a robust IMU as a base for a UAV project.
Read more…

FalconView - open source mapping application

Posted by automatik on January 23, 2010 at 9:55pm
In doing some research on ground stations, I came across FalconView - an open source pc based mapping software."FalconView is a PC based Mapping Application developed by the Georgia Tech Research Institute for the Department of Defense.The software is widely used by the US DoD and Allied countries, but historically it has not been available to the general public. Thanks to an initiative by the US Air Force, we have begun releasing a Free and Open Source version of FalconView."Guys from AeroVironment integrated it into their ground station. I came accros all this by vatching a video about Puma uav - link to video (it's in two parts, there is a comircial at the begineeing and middle of the video)Actually on EngineringTV you can find other informative videos about UAVs, robotics, and another engineering stuff.Maybe in future we'll integrate FalconView with ArduPilot GCS :)
Read more…
3D Robotics

Useful applications of amateur aerial imaging data

Posted by Chris Anderson on January 23, 2010 at 8:30pm

I'm starting to see DIY aerial photography showing up more and more often in day to day life. Here are two examples from this week: The above image, taken from a tethered blimp, is from this BoingBoing report: "Activist MIT cartographers aid Peruvian squatters": "This MIT Media Lab project worked with activists on Friday to make maps with a community of Shipibo who've taken up residence on the bank of the river Rimac in downtown Lima - a city of 11 million people. Using only helium balloons and a cheap camera, the GrassrootsMapping.org team, part of the Center for Future Civic Media, took pictures of the extralegal settlement from ~500 feet up. The images were rectified and the resulting map may help the Shipibo in their legal battle to gain deeds to the land. GrassrootsMapping.org is a project which supports communities in cartographic dispute by creating low-cost mapping tools." Meanwhile, this guy got his kite photos actually into the official Google Earth/Maps database, which is impressive indeed:

Needless to say, a UAV could have done either of these. The applications of "anytime, anywhere access to sky" are limitless!
Read more…

Results of first IMU flight tests

Posted by Magnus on January 23, 2010 at 6:06am
Today i made my first tests with a Gyro/accelerometer stabilized airframe. The system is based on an Ardupilot board and the Ardupilot expansion board with an additional gyro. The software is my own, but the Kalman filter is based on code published at the Sparkfun forum.The airframe is this 150 cm span flying wing:

In stabilization mode the ardupilot reads elevator and aileron input from the transmitter and uses this input as target roll and pitch angles. If the stick is centered the plane is supposed to fly straight ahead.The first flight tests were not a complete success. The Kalman filter seems to do a good job on the ground, but when flying i seem to get unreliable readings when turning. If i enable the stabilization et level flight it continues to fly level, but when i enable it during a turn it continues to turn rather than leveling out.My guess is that this is because the accelerators have to much weight in the kalman filter so when i make my perfect coordinated turns :) the filter is unable to keep its angles.I will keep you updated in this blog, but if anyone can give me some advice on how to tune the Kalman filter it would be appreciated./Magnus
Read more…
3D Robotics

Arduino meets Android

Posted by Chris Anderson on January 22, 2010 at 9:57pm
Check out Amarino, which is a toolkit to connect Android phones to Arduino microprocessor boards. Described as "basically consisting of an Android application and an Arduino library which will help you to interface with your phone in a new dimension. You can build your own interfaces almost without any programming experience."
Read more…
3D Robotics

Size comparison: ArduPilot Mega vs ArduPilot

Posted by Chris Anderson on January 22, 2010 at 4:30pm

Many of you have asked for a side-by-side comparison of ArduPilot Mega and basic ArduPilot, so here it is. Note that with Mega, we moved the servo and GPS connectors to horizontal rather than vertical placement, to make them more robust in the case of a crash. As you can see, the main processor in ArduPilot, an Atmega328, is just handling RC input and the failsafe function on Mega, while the main CPU has been upgraded to an Atmega1280, with more than twice as many I/O pins. In a sense, every chip has been upgraded to their big brother on Mega to handle more channels, sensors and communications paths. Basic ArduPilot, especially with the Turn-Rate Limiter Shield, will continue to be sold and will be the best plug-and-play solution for newcomers, while Mega will offer more capability for more advanced users.
Read more…
Developer

Do you want an ArduPilotMega board? (Limited)

Posted by Jordi Muñoz on January 22, 2010 at 2:30pm
I know some of you want to help and also for those that can't wait to put their hand's on the ArduPilotMega board here is your opportunity: You can be a Beta tester!The final version of the board will almost the same, just some small corrections like an extra set of resistors pads i added just in case that will be removed in the final version, right now are just bypassed.The requirements for being a beta tester are:-Have and know how to use an AVR ISCP Programmer (i recommend the AVRISP MKII), to upload new HEX's just in case we decide to change the PPM encoder firmware.-Windows XP/Vista/7.-Have a FTDI cable programmer.-Know how to use Arduino Environment and some basic programming skills.-Have a clue what digital electronics means (If you are a regular user or a certified noob, i don't recommend this board to you right now).-Willing to share your experience!-Have $38.90 dlls $44.90, i'm giving the board almost to the production cost (for low quantity's). The final version may cost up to $65 dlls!If you are ok with all this, you are welcome to get one board right now:http://store.diydrones.com/ProductDetails.asp?ProductCode=BR-ArduPilotMega-01The boards come with firmware (for AT328) and bootloader (for AT1280).I will be posting news&updates on the comments.I have a basic firmware that reads and decodes the PPM signal and display the 8ch PWM's into the terminal:APM_demo.zipThe folder "PPM_Decoder_AT1280" is located the code for Arduino IDE. On the folder "PPM_Enconder_AT328" is the firmware for the PPM enconder, if you have Windows and the AVRISP MKII just double click on the .bat file and press any key and it will upload the hex to the board, make sure to connect your programmer on the "AT328 port".PPM Encoder configuration:-MUX is controlled by input CH5.-Throttle FailSafe is input CH3 (Futaba).The Eagle Files of the Board are here:ArduPilotMega_v10.brdArduPilotMega_v10.sch
Read more…
Moderator

Atto Jack in the Box

Posted by Gary Mortimer on January 22, 2010 at 12:29pm
Chris Mc Nair has been playing about with things.

Boomerang flying wing UAV parachute failsafe hatch test. from Gary Mortimer on Vimeo.

To be fired by the Millswood crashinator, and oh so close to an off the shelf OBC airframe!The first thing to be added whilst thinking about what actually might be allowed, the second thing is being added but now there's a new second thing so that might make it a third thing.All a bit of a secret.The crashinator can also control cameras!
Read more…

THIS WEEK IN MARCY 1 AVIATION

Posted by Jack Crossfire on January 22, 2010 at 1:27am

Decal applied.

Ground station packed in. Battery sensor calibrated.

This design did not achieve horizontal control. The pitch oscillationfrom not having enough balance beam inertia offset any horizontal force.

This redesign did achieve 2 horizontal changes of direction using onlythrottle modulation. Unfortunately she threw a propeller &disintegrated upon crashing.

Marcy-1 was already very prone to throwing propellers, her 5300kV motorseemingly at the limit of Chinese plastic. We have a 4' monocopterplanned for extremely long duration hovers with normal RPM.There it is. XYZ positioning using only throttle on the Marcy 1 vehicle.Unfortunately not enough authority to move upwind, so we only gotcrosswind translations & a slower downwind drift than if cyclic wasneutral.As Mike Bakula recommended, used raw magnetometer output & detected whenthe halfway point in the waveform was crossed. Much better than usingderivatives like MIT since the derivatives are very noisy.Very important to have the balance beam loaded as much as humanlypossible to prevent pitch oscillation. Having the motor & battery onthe balance beam is the easiest way to load it. She did indeed bank inthe direction of the translation from throttle alone.An aileron servo would do better against the wind but it would be heavy,expensive, & wear out fast. No way a servo would cycle 6x a second forvery long. If you're gonna use 2 PWM, there's no point in a monocopteranyways but it's probably unavoidable for any long duration, outdoorvehicle.PROPELLER TERRORISMFinally got a flight in no wind & drizzle & she was easily controllableusing only 1 PWM. She was very sensitive to breezes.1 problem was power level changes when applying cyclic which we actuallylearned to handle. Greatest horizontal thrust comes from gliding herwhen applying cyclic. You can stall the motor this way so she justapplies thrust in 1 direction yet stays in the air. Greatest verticalthrust comes from releasing cyclic. Power management on a monocopter isa new artform.

The mane problem was broken propellers after 6 minutes. That's right.The GWS 3x2's are just not strong enough to provide hovering power.Marcy 1 is perfect in every way but dead without a stronger propeller.Ideas range from griding them down to 2.5x2 & using 3x3 if the weatherever improves.

3x2 ground into a 2.5x2SONAR REVIVALGetting sonar working on a new flight computer & new radio is nevereasy. The mane problem is actually the microcontrollers & tools. Everynew microcontroller has a different register set. If you want SPI,magnetometer, & 3k of RAM that means capture compare & analog need to berewritten.Also, the MRF49XA takes so much more CPU time to service than the XBee,sonar had to go on a dedicated USB device, making it more expensive touse 8 bit PICs than 32 bit ARMs.3 years ago ARMs were $10 & really tough to solder. Now they're $2 &easily soldered. PICs are only still around because of code reusethough ARMs need a lot more pins for programming.Building a 100Mhz computer from scratch using an ARM has always beenalluring, but the only motivation now would be going back to embeddedautopilots or a huge price advantage with ARMs.SONAR THEORYThe trick with sonar is to synchronize the clocks on the ground station& aircraft. Vika 2 did it by sending 1 beacon to the ground station &aircraft simultaneously. Marcy 1 doesn't have sonar on the same USBport so there's a significant rewrite already.

The complete Marcy 1 sonar guided kit, applying all the sonar knowledgegained from Vika 2.

The standalone sonar board is the simplest possible.Now more views of the machine with 3x2's & loaded balance beam.

Sonar installed, magnetometer in the stock & this thing which tellstime. Wow that sounds neat.

Making the sonar crash resistant is going to require a new fuselage.

Aren't you glad you didn't need to solder this. This is standard forChinese toys though not Air Force grade except for the name.

Balancing act.

Final look before crashing.
Read more…

Setbacks and Batteries

Posted by Jason Lyons on January 21, 2010 at 7:09pm
Well, after playing more with the IMU, the roll gyro has stopped working! I performed a visual inspection of the breakout board, and didn't see any shorts or signs of arcing. I reworked all the solder joints, making sure none of them had come disconnected. Finally, I removed the gyro daughter board from the IMU and tested it on its own, still no luck. The self-test function also is not returning anything, so I think it's stuffed.What a pain in the ass! Just as I was starting to get somewhere with the Kalman. Fortunately Sparkfun have offered to take a look at it and see if they can figure out what's wrong (and perhaps replace it!), as at the moment I can't afford buying any new sensors ($30 shipping every time is a killer!). If I have to buy a new one, I guess I'll have to wait until I have enough cash for a GPS unit, magnetometer and TTL->USB board as well so I don't get nailed for shipping twice.In the mean-time, I ordered some LiPo batteries for super cheap off ebay (E-Fly 2S, 900mAh, 15C), 3x batteries for $10! And only $10 shipping (from Hong Kong). I know what you're thinking.. never buy cheap & nasty batteries, but this is a low-budget project. I'm hoping these batteries will replace the 8.4V 650mAh NiMH batteries that my helicopter has been flying off, and that the weight saving will give me a bit more leeway with my autopilot payload. The only thing that I am concerned about, is that if these LiPos have built-in under-voltage protection (ie. switch off after reaching 3V per cell). Is that standard on all LiPos these days? Being a no-name brand, I couldn't find any specs on the batteries themselves..If I can sort that out, hopefully I can blow the dust and cobwebs of the heli and get some flights going this weekend to re-balance the helicopter and trim it right up.
Read more…