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"If you have an iPhone or an Android, you have all the sensors and technology necessary to fly an airplane," Chris Anderson says. Anderson is editor-in-chief of Wired magazine. He started a popular drone website and founded a company that sells drone parts. He says business is growing 50 percent a year. "Right now, the vast majority of people are doing it for fun, education, learning, you know, just the sheer thrill of having a flying robot," he says.

http://abclocal.go.com/kgo/story?section=news/assignment_7&id=8706281

DogfightOSD is a custom firmware for the popular Remzibi and MinimOSD boards that allows your plane to broadcast its own position data (lat/lon/alt) and receive and display information received from a second aircraft onto the display. To this end, a RFM12 short range radio board is connected to the OSD board via some simple hardware modifications. Currently the Remzibi version is ready, watch the video above for an impression of the functionality.

We're working on the minimOSD version at the moment. Once that's finished, expect a video with a dogfight between the two versions!

For the Remzibi board the hardware modification is really simple: Just free up the additional analog pins (two of the pins had resistors connected to them on my board), and connect the pins to the SPI connections available on the bottom-center of the board. In the picture below you can see the blue wires on the Remzibi board doing just that. Then connect a Jeelabs board with an RFM12 radio on it to the five pins. That's it! (and upload the custom firmware ofcourse...)

For more information on this project, and to download the firmware, please go to http://code.google.com/p/dogfight-osd/

Currently only the Remzibi binary is available for download, sources will be released shortly.

On Instructables I found a very nice project of a storage/carrying case of a quadcopter.

It also have the DFX file available, but I the dimensions depend on size of your copter, so might have to be adapted to fit the jDrone or the 3D copter.

Another carrying case I remember is the ArduPirates coffin: probably a safer way to bring the copter around, all wrapped and safe in all that foam, even if a bit less nicely crafted.

Has anyone else built custom cases for bringing their quad around?

If you have an aversion to cheesy 80's tunes, I'd recommend hitting mute. Otherwise, enjoy some of the antics of the day!

With the soldering on the APM2 complete (I think) it was time to move on with the stack up plates for the quad. For those who have not put their hand on an APM2, the Xacto knife with #11 blade provides some scale.

I am using aircraft plywood (it is on hand and paid for) rather than the FRP/G10 that is popular. Using ancient methods of razor saw and ruler, three stack up plates were cut and the process of making a home for the APM2 was initiated.

Some tolerance creep has set in but that is normal with a mixture of hand and machine tools. I wanted the wiring to pass up through some of the boards rather than outside the stack. This may provide a neater harness and offer some protection against impact damage.

Having a Mini Mill comes in handy on a project like this. The cable slot was a cinch to cut after penciling an outline. I used a 1/8 4 flute end mill to do the cutting. Sandpaper was used to finish the edges.

I marked the APM2 holes, drilled them, and then counter drilled with a 1/4 end mill to sink the nylon standoffs into the plywood. This reduced the length of the mounting screw needed to hold the board in place.

After turning down (with my 7 x 12 lathe) some aluminum threaded hex standoffs to clear the electrical parts on the board, I cut a plexiglass plate to cover the APM2, drilled it, and found appropriate screws to hold the lid on. The 4/40 screw heads are on the bottom of the plywood plate. They pass up through the nylon spacers, through the APM2 with the pcb held down by the turned end of the aluminum standoffs. I colored the hex end 'knobs' black with a Sharpie to add some style to the mount.

Here is a idea: Perhaps using plywood will dampen vibrations in the system? I can also employ some RTV/Silicone washers if vibration is more suspect. Frankly a proper balancing of propellors would go a long way to reducing vibration on a quadrotor.

Next task: The stack plate for the Spektrum RC gear (main and remote). I actually cut/drilled three plates prior to the APM2 final machining. I've got two blanks to go.

3rd time for this APM2 and 3DR radio combo ! The temps ranged from 100 F on ground to -51 F at one point in flight.

We did have a failure on the 3DR radio at -51 F. Radio died and won't come back.

We used the APRS.FI tracking as well and it showed great.

As you can see, there is NO insulation in our fiberglass box. Cameras on outside have no insulation.

All electronics worked for 3 flights now and still work (except the 3DR)

Sparkfun datalogger worked this time. I need to DL the APM2 data yet.

Earl

Hi guys,

Today I've found a way to recycle broken propellers and it works perfectly. ;) I wanted to share it!

Came across this very interesting article on the register

"A British-led Japan-based group is building a free-software-powered flying robot for use by disaster relief organisations – and at its heart is tech darling the Raspberry Pi.

There are lots of uses for the £30 Pi, from an educational device to a media player, if you can get hold of one of the boards. OpenRelief is planning something rather more ambitious: to use the credit card-sized computer as the brain of an autonomous flying drone – not as a killer robot, for once, but to help save lives instead."

More of the article http://www.theregister.co.uk/2012/06/12/raspberry_pi_drone/

So I thought I would get some close up shots and higher res video to show some of the finer details of the launcher. Like most things in this hobby it didn't go to plan as when i went to take off the Esc and Motor smoked themselves, so no launch, and after borrowing a friends motor found that he uses 4mm motor connectors and I use 5mm so no go there. Anyway here are some pics.

set and ready to go,

front pulley and release trigger.

Front legs and

Front Legs.

Ram about 1/4 out.

Front trigger about to release.

Trigger Realised.

regards Richie.

The Sparkfun AV Challenge did not disappoint... Dizzying highs, crushing lows - it had it all!

Congratulations to team 'Overhead', Patrick and Trevor for taking out 1st place in the Aerial division (along with all who competed and provided us with hours of entertainment.)

For those who were unable to attend, click on this link to check out photos of the day. I have over 50 clips of video to wade through so expect some fun footage soon!

I know that this is simply another APM2 installation, but I thought I would post it anyway in case anyone might be looking for suitable airframes for their DIY drone.  Also, this is kind of exciting for me since I am finally doing my DIY drone project and like to share my activity.  While my dedicated UAV build is underway, I'm testing APM2 and its accessories in a SkyFly Max.  I already had this airframe, but it would be one to consider buying new.  It's inexpensive, easy to hand launch, and seems to have been sized for APM2.  I put APM2 in the upper equipment bay and located the RC receiver in the lower bay (I love using those technical terms on a park flyer!).

I made a small box for the 3DR transmitter.  I was a little concerned about heat, but it's not airtight and it sits in the airstream.  I'll be mounting the ESC outside like the 3DR radio as well.  It normally sits where the APM2 is now, but I also want to isolate it from the other electronics in case the ESC itself overheats.

My brother is my partner in this project.  We're doing this in stages.  First, we breadboarded the entire system outside of the airframe.  I had the task of walking that tray of electronics around his backyard pretending to be plane and hitting waypoints.  I can't imagine what the neighbors were thinking!  Our next task is to get APM2 working in simulation.  Only then will we move on to flight testing.

Thanks,
Paul

Think you have challenges getting that sonar, airspeed sensor, or magnetometer to produce clean data in the harsh environment on your Skywalker, with ESCs, RF fields, 65mph winds, and multi-G impacts? Well, the guys over at NanoSatisfi are looking for a new level of pain, and have a kickstarter to put the ArduSat into a polar orbit.

Rather than simply launch their payload into space with a load of sensors and some experiments, they are embracing the larger spirit of an open project, and are sandwiching in several arduino-based boards, with the intent to run your experiments. Various options to beam your message down to Earth, take photos or otherwise run your program have been outlined. They have a host of different sensors for your program to I/O block, filter, calculate the median value, and compare to a fluctuating reference voltage.

Normally, I like to provide some details for a blog entry, but for this one, I'm going to let their project speak on its own.

Dvice has a nice story and overview, and the kickstarter page covers the details, and provides ways you can support the project. Here is a sample:

"ArduSat is a miniature cubic satellite, measuring 10 cm along each edge and weighing about 1 kg. Onboard it will have a suite of 25+ sensors, including three cameras, a Geiger counter, spectrometer, magnetometer and more (check out the FAQ below for a full list). The sensors are connected to a bank of user-programmable Arduino processors, which run your application or experiment, gathering data from the space environment."

Here is the video pitch, for your viewing pleasure. 

Personally, if I were these guys, I'd want someone to talk me into joining the DIYDrone's very own Team Prometheus and BLUAS groups.  They can use these teams' methods to trial and test the gear in high altitude balloon launches before I fired this gear into orbit, and avoid some of the potential for public embarrassment and project failure when learning that the GPS was an MT 3329 rather than MT 3339, that the resistors became superconductors at near zero kelvin, the RF field from the telemetry link was generating spurious signals on all the analog sensors, the alternating heat/cold caused the inter-board connectors to swell and contract like an accordion, and the moisture inside the Pan/tilt servos locked up the gears... 

It's space. Where even AVRdude will not help you debug. Err ... scream. I'm thinking there is a good chance that the guys behind this project are already members here. If so, maybe we can give them some constructive questions and ideas. And our support. But if you have to get your Arduino-rant out, go ahead (you know who you are, you lovable rogues.) Just be brief, we've all heard it before, and this project could generate discussions that are actually interesting, possibly even helpful in solving our own sensor, electrical, and environmental challenges. 

Today I christened my new plane launcher with success. I have built this as I have found the properties where I want to fly from have little or no adequate takeoff areas since the fields are full of waist high grass or lots of rough ground. Landing is OK by slowing down and dropping into the long grass but takeoff has been hazardous, to say the least.

The launcher is using an 900mm air ram to drive a 6:1 ratio pulley system that accelerates the launch trolley up the ramp. The ramp is made from 2 x 50mm x 25mm C sections welded together and bolted together in 2 x 3m sections that can be broken down for transport. 

The trolley has a front wheel hold down that is released at the end of the ramp and hopefully this coincides with flying speed.

The speed is adjusted by altering the air pressure from the compressor. So far it is launching at approx 100 psi without ripping any wings off. As the compressor is rated to 150 psi it has some spare capacity for larger or heavy flying weights.

So far it costs about $300, the ram was an ebay special for $50. I sourced the pulleys from ebay by buying someone's unused gym weight machine, which has 125mm glass fibre pulleys complete with bearings (which to buy separately would have been $15-20 each.) I was also able to use some of the gym machine's steel for legs and some of the frame.

richie 

tl;dr: nice!

http://eastbay-rc.blogspot.com/2012/06/checking-out-arducopter-26.html

and a demo of Failsafe with a Turnigy 9x / FrSky module.  Binding the failsafe to "land" and then switching off the Tx.

 
It does work on the test stand, for the most part. There's a lot of lag. There's a dead area directly on the axis of rotation. The range of working ambient light is very narrow. The mane limitation is not knowing where the axis of rotation is in the frame.

  The altitude was manely unaffected by bank.  X & Y were pretty bad.  There is an oscillation from the rotation.  If 1 frame per rotation is counted instead of the 3 in which the blob is visible, the oscillation would go away, but fewer data points would be averaged.

  X & Y seemed roughly aligned with magnetic N.  Further alignment would require stabilizing the test attitude.

The mane event was devising every possible test for position sensing.  Position sensing from a rotating camera & all the trigonometry required was too crazy to believe it would work.  There were a lot of electronic dongles hanging in mid air.  Crashing would get expensive.

When Marcy 2 was originally conceived, there was full confidence that everything currently on the air frame was physically enough to do the job.  Confidence wanes when it's built up & sitting on the test stand.

The leading technique was the old ceiling hung wire, but it didn't constrain bank angle.  As expected, the bank angle drastically impaired position sensing.  When level, the azimuth correlation & blob detection seemed to work.

There were a lot of obvious glitches which the deglitching couldn't handle.  The camera detected noise as the target when pointing away from the target.

Thus, the error prone test of a minimum blob size was required.  Manely, the largest blob in the last revolution was taken.  Then, all blobs below half its size were excluded.  A blob greater than 1/2 the maximum could sneak in when the camera was pointed away, for which deglitching would be required.  A real paranoid filter could take only the largest blob from the last revolution.

She already has trouble differentiating from the Heroine Clock.  This is the reality of machine vision.

The quest for a more robust electronics arrangement continues.  The mane board can be repaired, but the wifi card has a $5 tag & works better near the axis of rotation.

Fly & crash she did.

 Revealing no useful position information during the flight.  The takeoff attitude hold was so accurate, it kept the target halfway off the screen during the complete flight. All the energy getting the camera to view the axis of rotation didn't get enough of it in view to give a target.

  The attitude hold stays active until the takeoff altitude is reached, just like ground based vision.  Only then does it switch to position hold.  It's probably acceptable if the takeoff altitude is low.

The current blob won't do.

Then there were 2 markers.  Sunlight caused some blue in the chromatic aberration. 

Having 2 markers creates a lot of possibilities.  The overlap of the 2 markers can be used to throw out false blobs, but also eliminates some real blobs.  The distance between the 2 markers & size of the 2nd marker can give a better distance measurement, but the distance is affected by rolling shutter.  The blue marker can be visible sooner in the takeoff.


You can see how more targets could be added & detected based on proximity.  Then, the position could be even more refined.

Of course, blue immediately showed the same horror glitches it did before.  Light blue might work better, but it's not mass produced.  Maybe if all blobs were thrown out that weren't a red & blue next to each other.

That was disappointing, but there's hope some simple shape detection is possible or some redundant marker can work in the 1st moments of takeoff.  Such a diabolically complicated system like that brings to mind the idea of detecting position from a partially obscured blob.

The radius & center can be derived from the dimensions of the rectangle.  But that also depends on rolling shutter.

A 2nd pink circle would be hard to separate from the 1st.  Enough testing could define a minimum distance to resolve the 2.  Then they could be mounted on a blue background, guaranteed to not generate a false positive.  How would it know where the maximum distance between the 2 blobs ended & ambient noise began?

It could measure the size of the small blob & compare it to the distance from the big blob. 

The small blob isn't big enough to get any size & if only the small blob is visible, it'll trigger a false positive.  The scanline compression takes away a lot of photons.  Some rough, procedural shape detection may be the only way.

A line was also worthless.   At flight speed, it takes a lot of photons to trigger the mask.

Blob matching based on overlapping boundary boxes of the red & blue got rid of some pretty significant blue noise.  Boundary boxes aren't as robust as scanning every red pixel for a neighboring blue, but faster.

The final attempt in this red/blue combination was scanning every red blob pixel for adjacent blue pixels & taking the largest blue blob.  This was bulletproof at separating the red/blue marker from the noise.

It was a leap in intelligence, actually detecting details in a noisy image from a spinning camera, with complicated rules for switching to the blue blob when the red blob was obscured & throwing out all red blobs without an adjacent blue blob, except during takeoff. 

Surprisingly, the blue & red blobs seemed to give very consistent results, right down to Y offset between blobs.


In the worst case, 1 original plan if the camera couldn't look straight down was to have the red off center for all position sensing & the blue for the takeoff leveling with a new requirement to not hover directly over the red.

Another test flight & another crash as the denoising algorithm throws out good data.  If the aircraft rises too fast & the blobs get small too fast, they get thrown out for being too small.

There were only 20 good frames it could have used during the takeoff, if it worked.   

Anyways, started thinking more about tethered power.  The 10 minute flight time & cost of crashing batteries over the years is such a turnoff, it makes you think surely the infinite flight time of a tethered system can outweigh the drawbacks.

It's been sold before as a finished product, with limited results.  Maybe it was sold to the wrong customers.  Someone interested in a flying camera for photographing on a closed set would be better off with a tethered system.  Hobbyists are manely interested in hovering a camera in a stationary location.

The mane limitation of all FPV videos is they have a very limited horizontal range, beyond which they always have to turn around.  It's hardly enough justification for batteries.

The ideal tethering system has an insulated wire for V+ & uninsulated wire for ground.  The wires are as thin as possible.  The voltage on the ground is much higher than the motor voltage, to compensate for resistance.  The motors are wound for very high voltage & low current.

The monocopters can't be tethered.

Modern fault-tolerance design for aircraft does little to help when big parts start falling off. This study proposes a design approach / philosophy for keeping things aloft during broader system failure.

From PsysOrg: /
"For example, the group studied the plane’s operation during a maneuver called the “Dutch roll,” in which the plane rocks from side to side, its wingtips rolling in a figure-eight motion. The potentially dangerous motion is much more pronounced when a plane’s rudder is faulty, or one of its engines isn’t responding. Using their design approach, the group found that in such partially failed conditions, if the plane’s tail was larger, it could damp the motion, and steady the aircraft.

Of course, a plane’s shape can’t morph in midflight to accommodate an engine sputter or a rudder malfunction. To arrive at a plane’s final shape — a geometry that can withstand potential failures — de Weck and his researchers weighed the likelihood of each partial failure, using that data to inform their decisions on how to change the plane’s shape in a way that would address the likeliest failures.

De Weck says that while the group’s focus on failure represents a completely new approach to design, there is also a psychological element with which engineers may have to grapple.“Many engineers are perfectionists, so deliberately designing something that’s not going to be fully functional is hard,” de Weck says. “But we’re showing that by acknowledging imperfection, you can actually make the system better.”

Story
I was wondering about PPM decoder for a while. I liked to have receiver on edge of the wing, but routing of all servo cables there is nonsense.  My idea to build one came from accident when I damaged my one of APM1’s main MCU  I2C pins. I replaced it with new one and then I get idea to reuse damaged MCU for PPM decoder (I2c wont be needed) They are not cheap (ATMEGA2560 are 18$ in mouser) and it's a pity to throw it away. I realized that APM uses sum PPM signal and can drive 8 servos by hardware timers and has libraries for it so software can’t be too hard. I fired up Eagle and started to draw....

Hardware design
I peeked in schematic of APM1 and duplicated servo and PPM pinout. Basically, you can use APM1 without oilpan to do the same! Then I realized it would be a good idea to do galvanic isolation of receiver to suppress any interference coming through the wires. This is really simple, just isolated 1W DC/DC 5V/5V converter to power receiver side and ADUM1301 isolator IC. Simple optocoupler would do the job well, but I was too lazy as ADUM’s are really simple to work with. It is quick and dirty design at all, board is autorouted with some hand corrections. Parts are chosen to be obtainable in local store here in Czech.

Prototype
I soldered all stuff on board, powered it up and arduino bootloader was not answering :) Long story short, failed crystal. With new one, everything goes well. I still haven't ADUM1301 IC, so there is a piece of wire instead. But receiver has its own power via DC/DC.

Software
This was easies part. I just compiled \ArduPlane-2.32\libraries\APM_RC\examples\APM1_radio\APM1_radio.pde it was all I needed to do! This example is doing exactly what I needed. Decode PPM signal and send it to servos. Well I commented out serial debug messages and added blinking of LED.

Real life tests
I was really brave (or stupid) to put this to my greatest, most expensive and most labour intensive plane ever, UltraMaxiSwift (will show it in another blog post) and even together with my own OpenLRS clone. Everything is working well, it has about one hour in the air.

Future development
When I fix my APM completely, it will replace this decoder. Maybe I will use it in other plane.
But one thing worth to be experimented. If I add second PPM receiver, Decoder can do a sort of diversity. It would choose valid PPM signal from second receiver if first goes to failsafe or vanishes completely.
Is ATMEGA2560 (or 1280) able to decode second PPM stream? I offer piece of hardware to someone who will write software for it :)

Pros and Cons
+ Place receiver freely in airframe
+ Galvanic isolation to help avoid interference
+ Possibility to alter RC signal (mixer, complex failsafe...)

-When this thing fails your plane is doomed
-Not need when APM onboard as it has PPM input
-ATMEGA2560 (or 1280) is expensive overkill for such simple task

Conclusion
If you like this, send my board design to your favourite fab house and DIY. Probably not needed by most of you. I wanted to thank all APM community for such great project.

rcisol.zip

Our friends at MaxBotix have updated their offering of ultrasound sonar sensors by adding the new High Resolution LV line. The defining characteristic of this new line of sonars is the 1mm resolution. Yes. 1mm. Well, more correctly, "the HRLV-MaxSonar-EZ Sensors offer calibrated 1 mm accuracy of 0.1% at 1 meter," so at greater distances, the ranging might be off by a millimeter or more. Up to 5 millimeters at 5 meters, if the accuracy were linear. I can live with that. *grin*

The new sensors offer a similar near end range, a minimum of 30cm, and the data sheet describes a 5 meter maximum range. This is slightly shorter than the 6.4 meter maximum range of the LV line or the 7-10 meter range of the XL, but my thinking is beyond 15 feet off the deck, you might not notice if your multicopter switches to using the barometer for alt_hold. Like the other product lines, the specifics of range are most likely subject to the beam pattern. As with the LV line, it is available in a variety of beam patterns off the shelf, and they offer custom solutions for customers who require it. 

This new sensor line offers the same interface as existing sonar products, including analog, serial/TTL, and pulse width, comes in the same form-factor we to which are accustom, but the manufacturer provides details on additional distinguishing characteristics of this new line over the LV line, including:

• Higher resolution output
• Automatic calibration of, noise, humidity, and voltage for consistent, long term, operation.
• Automatical compensate for speed of sound changes due to the effects temperature changes
• Advanced firmware to handle a variety of noise sources
• Simultaneous multiple sensor operation
• Noise filtering is even better than previous MaxSonar products
• Automatic target size compensation

With this level of resolution, I expect there are new technical challenges related to air temperature changes in near-real time, and this suspicion is somewhat supported by two features of this sensor. First, there is it's onboard support for compensation of "self heating" through an onboard temperature sensor. Second, there is support for an external temperature sensor, also available from MaxBotix, which when combined with the onboard temperature sensor, can eliminate a potential "drift of ... up to 3%."

The product page also reports that the HRLV are designed to support simultaneous sensor operation, but it is not clear from the initial information if this is handled through time triggered operation, as with the other sonar lines, or if this sensor discriminates between its pulse and those of other nearby sonar units in some new fashion.

Here are the beam patterns available off the shelf. 

There are a range of other features worth discussing, but let me not distract you from the important questions. Or rather, the important question. With this type of high resolution, I would expect this sonar to come at matching high price. Like the LV and XL lines, different sensors are priced differently, but t The lineup is advertised at MSRP $28.95 - $34.95 for a single sensor, with volume discounts available.

I should mention right now that I have no ties to MaxBotix, except as a fellow customer. I don't get any discounts by bringing this news to you, and at these prices, I don't really need any (but I'd gladly go in on volume purchases if anyone wants to organize some, hint-hint 3DR team.) I was notified by email about the new line in a product announcement email. And that is important to this audience because it also informed me of another useful bit of information. These sonars are begin offered at a 25% discount until 7/15/2012 if you use the discount code en4v en4V [the code is case sensitive.]

A quote included with the product announcement (not attributed):

“1-mm resolution is so stable, that when measuring typical objects at a distance of one meter, the readings do not change by more than 1-mm.”

See the linked data sheet or the product Web page for more information.

As is customary and traditional, we celebrate every new 1,000 members here and share the traffic stats. This time it's 26,000!

There were 1.3 million page views this month. As usual, it took us four weeks to get this latest 1,000 members--we're averaging about one new member every 43 minutes.

Thanks as always to all the community members who make this growth possible, and especially the moderators who approve membership applications and blog posts and otherwise answer questions and keep things ticking here. We've got about 50 moderators now, but if anyone would like to join this group, please PM me. If you've been here for a while and have been participating, you'll fit in great.