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Mr.RC-Cam

Artificial Horizon

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The R/C parts I needed finally came in this week. So, the model is now complete and ready for a test flight. All I need is a relatively calm day and a couple spare hours. ;)

Here is a photo that shows the goodies mounted on the SlowStick's aluminum fuselage:

post-6-1087573588_thumb.jpg

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Latest video: http://www.rc-cam.com/avi/osd_demo4.mpg

Despite the miserable wind, I decide that a test flight was deserved. The good news is that the system is working decently, at least from what I envisioned. I definately need to tweak the gain curves a bit more (roll is too sensitive). My test flights were at low altitude, so keep that in mind.

The video would have offered a better demo if I could have sustained some level flights. As it was, just keeping the model upright was a real chore. But, you will get the feel for the system from what is seen here.

The bad news is that it was so gusty that I watched my model get slapped to the ground on a final approach. The small amount of carnage is being repaired. SlowSticks hate the wind.

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This is an excellent video for so many different reasons.

1) The onscreen pointers are totally cool. Am I the only one reminded of the health monitors in the sick bay on the old Star Trek series? :)

2) The video quality was very solid... what receiver antenna were you using?

I'm pretty jazzed specifically about the elevation indicator... the ability to keep the planes nose up in a turn seems like the key enabling technology to allow someone to fly a plane 'under the hood' without a lot of previous flight experience on the aircraft. I will only fly a plane under the hood after having reviewed a lot of tape from the plane's perspective so I know what 'level' looks like. Having a concrete, onboard indicator of this is pretty exciting.

Bill

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YB2normal -- I was using my home made patch. The video RF system is your 200mW 5V rig. Camera is a Panasonic GP161.

I hadn't thought about it before, but the little glyph pointers do look like something from Star Trek's sick bay. That may explain the flatline on the last flight (dorked it into the ground and broke some stuff). ;)

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It looks great. I have to admit it was hard for me to watch both glyps and horizon and see if they match. I am looking forward for another video with less windy conditions. Great job anyway.

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Hey, it looks like it's working!

Did everybody catch the readout of the battery voltage that occured periodically? Neat!

Good job!

I agree the gain looks a little too high. Also, I'd expect the relationship between sensor voltage and attitude to be non-linear. Does a voltage delta correspond to a constant displacement of the glyph, or do you use a look up table of some sort to try to "linearize" the sensor output? Something like an "expo" setting.

Again, good job!

Dave Thomas

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Did everybody catch the readout of the battery voltage that occurred periodically? Neat!

Thanks. That feature was troublesome to add, but worth it. Also, along with the onscreen v-display, the moving glyphs will blink like mad if the voltage is getting too low to allow continued operation.

I agree the gain looks a little too high. Also, I'd expect the relationship between sensor voltage and attitude to be non-linear.

I do not know what the relationship will ultimately be. I expect it to take several thousand feet before any impact could be noticed due to the altitude shift. I kind of expect other errors, like localized temperature shifts, to be more of a nuisance. And Cyber-Flyer has already shown that ground temperatures will bias the sensors in an odd way. These issues might make use of the IR approach, as a primary navigation aid, a bit problematic. But as a piloting adjunct/aid it should be very cool.

Does a voltage delta correspond to a constant displacement of the glyph, or do you use a look up table of some sort to try to "linearize" the sensor output?

It is linear. What you see is a displacement based entirely on the voltage (with digital gain) without any interpolation.

Something like an "expo" setting.

One of the many things I learned from the test flight was that an expo-like feature would be nice to have. For me, less sensitive off-center movement would seem best. So, besides adding entirely new digital gain parameters (now 15 user programmable steps), I recently created a stepped exponential compression curve. The new curve maintains linear glyph movement at center, but dumbs it down as it moves further out. It will be user-programmable (on/off).

Thanks all for the encouragement. I'll post more results in a few days.

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Nice video Mr. RC-CAM!

This is totally off the topic of making an Artificial Horizon, your video indicators have me excited but for a different purpose.

How hard would it be to connect the pilot view camera indicators you use to monitor 2 servos from a second (camera operator) receiver?

They would let the pilot know what direction to fly when the tilt-pan camera operator says “hey, I want to look at this”.

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Adding the ability to read servo pulses would require a bit more hardware. The over-burdened PIC does not have any free time to do that on its own -- too busy handling pixels. It is possible, but not without a new design (I'm too busy at the moment to consider it.)

Actually, I think it would be more useful if you could use your Tx joystick to move a single cursor onto the target zone. That way the pilot will know exactly what you are looking at and where to go. This too would impact the existing design, at least in a significantly S/W-like way.

There is another forum member that is working on an OSD design. Maybe he will give it a try? Here is the link to his thread: http://www.rc-cam.com/forum/index.php?showtopic=369

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There is another forum member that is working on an OSD design

Hey, you're talking about me!

I've been playing with video overlay using a Cypress PSOC instead of a MicroChip PIC. I'm really just getting started. I've got the syncgen stuff working (the equivalent of the LM1881) and have been talking with Mr. RC-CAM off-forum about how I want to proceed.

Basically, what you are asking for is on screen display of a servo pulse width. 1.5 msec pulse (neutral) would result in centered glyphs. Deviations from the nominal servo pulse width cause glyph displacements similar to how the AI indicates pitch and roll attitudes.

The flyer uses the indicator to get the heli pointed at the camera subject.

Have I got it right?

The PSOC has quite of bit of hardware resource available. An extra timer block time multiplexed between the two servo channels would be required. The nice thing about the PSOC is that not only does it have an abundance of configurable hardware resources, these resources can be dynamically reconfigured under software control. So its possible the chip could be programmed with a jumper to be either an character OSD or the servo pulse width indicator. The digital blocks for the the UART function could be used for the servo pulse width timer function, if digital block resource becomes critical--but so far I'm not hardware resource limited.

Mr. RC-CAM, do both the camera man and the flyer see the same display? If so, your idea (I think) of the camera man moving a cursor to a screen position that indicates the object of interest would make sense. But I thought the problem to be solved was that the camera man sees the object through one camera while the flyer is using a different camera. Hence, the difficulty in the camera man communicated the desired attitude change to the pilot.

Dave Thomas

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Mr. RC-CAM, do both the camera man and the flyer see the same display?

That is what I was considering. The cameraman and pilot share the same realtime video, cameraman coordinates with the pilot (via cursor) to get the shot lined up, then the cameraman shoots a still photo. But everyone has their own needs and such, so my method may not excite other folks.

It would be best to start a new discussion on this rather than take this one off topic. This thread should stick to the IR based AHI projects.

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New MAHI Demo Video: http://www.rc-cam.com/avi/osd_demo5.mpg

The wind was still at it today (5-10mph) but I decided to at least see if the new gain setting and expo compression features were correct. I am very happy with what I saw -- the gyphs are less goosy and easier on the eyes.

The model was still too wind whipped for me to get a good feel on how accurate the indicators are. I guess the SlowStick was a poor choice for a test platform. It really bounces around in anything but dead calm settings.

After seeing the video it looks my zero cal was off a bit (darn those shaded areas at the field). If you look closely you can kind of see that the roll horizon is not centered when the model is flying level. Next time I'll pay more attention to the field calibration.

At this point I think I should try to get a couple boards into other folks' hands. I will email a couple of you later in the week to see if you are interested in purchasing a programmed chip and a blank PCB. Later, if it gets a thumbs up, then I will create more boards and possibly a full parts kit. If it is not well received then its future will need to be reviewed.

BTW, I expect to create another software version that will serve as a video overlay that shows just your Ham Call Sign, Battery Voltage, and anything else I think will be useful. That will probably come out in the fall (should be a nice winter project for some of you that do not want a AHI, but like the other features).

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I've had a chance to assemble, test, and fly one of the MAHI boards and I've attached a link to a short video.

One interesting point.... the copilot sensor is fixed to the body of the plane while the camera is free to tilt down. This resulted in a bit of mental disconnect between what I saw on the video and how the horizon indicators moved, but on the plus side I could tell when I wasn't level by looking at the indicators.

Enjoy....

Right Click and 'Save As'... about 7 megs

post-6-1089409130_thumb.jpg

Edited by yb2normal

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Looking good!!!

If I can make a few small comments though....

Are call sign and voltage optional? Would be nice if it was for people arlready using other boards that do not need this info.

Also it looks like you loose one axis when these appear.

Perhaps have them flash on top center and not loose the axis indicator.

But definitely a VERY cool project Mr. RC-Cam!

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That was a nice video example. What model were you flying with? Can you post some photos of your installation?

BTW, the indicators seem to be pretty handy when the camera is looking down. With a little practice, perhaps a fellow could fly decently level in that mode.

Are call sign and voltage optional?

You can change the interval or disable these messages. They each have their own set of parameters. Perhaps Yb2normal can share what he thinks of the setup menu features?

Also it looks like you loose one axis when these appear. Perhaps have them flash on top center and not loose the axis indicator.

Without getting into the specifics of the constraints of the PIC based video system, the only practical choice I have is to post the status messages at the top or the bottom of the screen. I did not think the top was a good place because of visibility (white characters against light color sky background would often be hard to read). A more practical solution is to setup the status messages so that the call sign appears once every 5 minutes and the battery voltage once a minute or so. Since their duration is less than 3 seconds each, there really isn't much of a burden if you wish to use these features. You could easily stagger their interval times so that they both do not come up in a row (like as seen in YB2normal's video).

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That was a nice video example. What model were you flying with? Can you post some photos of your installation?

Sure! As far as I know I can only post one picture per post, so bear with me on the multiple posts to come....

Perhaps Yb2normal can share what he thinks of the setup menu features?

The setup menu was very easy to work with... on par with many of the menu based RC chargers. (and I meant that as a compliment ;) ) The only hard part for me was that my Sony camcorder is touchscreen based, and the camcorder VCR controls are overlayed on the LCD such that it was hard to see the RCCAM overlay menus. Fortunately I had stepped through them earlier on a TV so I could intuit what menu item I was on from the little bit I could see peeking out from behind the camcorder onscreen buttons.

You could easily stagger their interval times so that they both do not come up in a row (like as seen in YB2normal's video).

I intentionally chose a very short interval for both the voltage and call sign, because I knew my final video would only be around 30 seconds long, and I wanted to make sure both features were displayed.

Ok, here come the pictures....

First one shows the overall plane setup. You can see the copilot sensor perched on a tall support made of birchwood:

post-6-1089496180_thumb.jpg

Edited by yb2normal

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Next one shows the profile fuselage that I added to the slowstick to mount all the goodies... There are velcro strips running the entire length of both sides of this fuselage, and it is really easy to move equipment around to get the CG right or to add/remove different components being tested.

post-6-1089496456_thumb.jpg

Edited by yb2normal

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Here you can see the tilt camera detail. A strip of birchwood was notched so that it straddled the landing gear, and then a bit of carbonfiber tow was wrapped around the junction and soaked with medium CA.

After discovering how un-torsionally rigid the birchwood was I also added some CF fabric to the underside of the birchwood and liberally soaked it with CA.

The camera is the one I sell in my "Brown Bag" kits. It was inserted into a length of shrink-tubing after having ground off the mounting tabs. This was then Gooped onto the servo arm.

post-6-1089496790_thumb.jpg

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detail shot of the copilot sensor on it's birchwood platform. The tower is screwed into the slowstick boom with a single machine screw

post-6-1089496999_thumb.jpg

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Finally, a shot of the opposite side with the video tx, and plenty of real-estate for the batteries. I fly a 3 cell thunderpower 2100 for the motor (mega 16/15/7 run direct on a 9x4.5) and a 2 cell lipo for the video overlay, video transmitter, and camera

post-6-1089497116_thumb.jpg

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Thanks for the photos. It is always interesting to see how other folks cram their boat load of stuff onto a SlowStick. ;)

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Interested in a MAHI board & programmed PIC? If so, then PLEASE READ THIS:

I will release a few more PCB's/PIC kits as soon as the second beta tester reports his findings.

I do not plan to release the hex file. The only way to get involved in the project is to obtain the pre-programmed PIC and PCB from me. This is a huge departure from the other RC-CAM projects, but it is the best way for me to ensure I don't get stuck with a bunch of PCB's I cannot get rid of. Also, I may eventually commercialize the PIC based video board (it has potential in other apps) -- making the hex file public will harm that effort.

In my prior project offers I have sold PCB's at, or below, my costs. However, I did not do well with those (yup, I lost money and ate inventory) so this time I will have to mark up the items. That way I can recover my development costs and buy a burger or two every once in awhile.

The PCB's are purchased in low volume from fab houses that I trust. So, that means they will not be cheap, even for me. Just so that you can budget for the project, the PCB/PIC chip combo will probably sell for $29 to $40. The other parts, less the Co-Pilot sensor, will cost another $25 from Digi-Key. If there is enough interest, I will put together a full kit of parts so that you do not need to scout out the little items. It all depends on the responses entered in this thread.

The skill level needed to assemble the MAHI project is VERY high. If you do not have experience building SMT boards with fine pitched parts, or do not have the proper soldering equipment, then you will probably have poor success with the project. Please keep this in mind. In case I am being too hard on this, perhaps the two beta tester will comment on what skills they believe are necessary.

Here is the important part:

If you are interested in the MAHI PCB/PIC, then do NOT email (or PM) me. Instead, {until further notice} post a "I want one" on this ongoing thread. Some of you have already done this. But even so, if you are still interested then edit YOUR EXISTING email and add a tag line that says "I'm still interested."

This quirky request is so that I can determine who is next in line (by way of the datestamp) and the expected PCB count I need to accommodate. Just keep in mind that if you are the next to get parts, other folks will be very interested in what you find. So, get the soldering iron and magnifier ready! ;)

Edited by Mr.RC-Cam

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