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Mr.RC-Cam

Artificial Horizon

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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.

I think this is an accurate statement. Do NOT use this project as your first foray into SMT soldering.... try to find an SMT practice kit or a simple SMT project to start with.

With regards to proper equipment, I was able to get away with the following:

- two 15w radioshack fine tip soldering irons (two of them lets you pick off badly placed components)

- a tube of Kester solder paste... but stay away from the water clean-up variety, I didn't like the way the solder would bead up into little tiny balls completely unconnected to the pad I was soldering. The other variety will require a flux removing solvent, but it is easier to work with in my opinion.

- a set of granny reading glasses... the cheap ones you can buy at your local drugstore. Get the high power ones because you'll be soldering some components that are just a bit bigger than a grain of sand.

- a nice bright light over the workbench.

- a small fan to blow away soldering fumes... you'll have your nose about 6 inches from the board while soldering.

- a set of 'helping hands' to hold the board.

Regards,

Bill

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Mr. RC-CAM,

20 MHz crystal for MAHI project is on back order from Digi-Key,

Would you recommend any particular replacement?

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20 MHz crystal for MAHI project is on back order from Digi-Key,

Would you recommend any particular replacement?

They gave you bum info -- there are 956 in stock. :) P/N 300-6142-1.

I have small quantities of some parts. If you run into trouble then I will do my best to help out.

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I forgot to mention that the system is currently limited to NTSC and RS-170 video (color or B/W systems). Until further notice, it will not work with PAL, SECAM, or other broadcast standards.

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Hello Mr. RC-Cam

I have been following your fourm and now I have time to work on my

planes. I have worked on SMT projects before so I am saying,

"I WANT ONE"

Thanks

Midwest-Flyer

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RC-CAM,

Could you post the Digi-key parts required to complete the board? I need to place an order with Digi-Key this week so I thought I would just order everything at once.

thanks,

Mark

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Parts List: I would like to wait for the second beta tester to report his findings. The design will be locked down once it is established that all is well.

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They gave you bum info -- there are 956 in stock.  P/N 300-6142-1.

Yes, I've got the part. It must have been a glitch on Digi-Key computer, or they have run out of stock when I've tried to order.

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Yes, I've got the part.

That is good news. If you run into any other shortages then keep in mind that I may be able to source it. I have a little cache of spares that I may be able to steal from.

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Let's check to see if my "I want one" list is correct. From what I can tell, these are the folks that clearly want a MAHI PCB and PIC:

mark, 7-12-04 05:44

ensignnolo, 7-12-04 7:44

wamdue, 07-12-04 10:44

midwest-flyer, 07-12-04 16:20

carlei aeromidia, 07-12-04 16:56

"I'm still interested list:" Here is the list of members that mentioned long ago they were interested, but have not recently posted that they still want a PCB & PIC. If they respond in the next few days they will join the list in the order they first showed an interest:

diyguy

juzzac

crashpilot1

temporary Insanity

radioflyer

DO YOU WANT TO BE A BETA TESTER?

To help get things moving forward, I will release two additional beta packages (PIC and PCB sets) this week. These will be sold at a slight discount -- perhaps a couple bucks less than the released version's price. Payment must be via PayPal.

To qualify, you must be a forum member that is located in the USA, be able to follow minimal instructions (build from schematic & parts list), have SMT soldering tools & experience, and sufficient enthusiasm & time to obtain the necessary parts to get your board built/tested in short order.

You must also be prepared to fly several flights with the system. Your experiences with building and using MAHI will be used to help validate the project. You may be asked to make some simple measurements. Software bugs, if any, would be handled by a PIC exchange method.

The usual small print: Please keep in mind that this device is experimental. If a beta tester is not satisfied with its performance then all I can do is refund the costs of the PCB & PIC that I supplied. Users must take full responsibility for any incident that may arise from the use of the device.

If you are interested then please contact me via the RC-CAM PM feature.

Edited by Mr.RC-Cam

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Corrections made. Thanks for catching that!

Here is another MAHI demo sample taken from a flight this evening. Nothing new, but still a lot of fun to watch the little axis markers move around.

CLICK HERE TO SEE DEMO #6.

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I have been following this thread for some time; great work, everyone! I am curious why both Mr.RC-Cam and yb2normal chose to mount the FMA sensor pack so far above the wing? I am installing one on a plane right now (in standard configuration, not for the awesome uses shown here) and am following factory instructions to mount it directly behind the cockpit.

What are the advantages to mounting it high above the wing as shown in the pics above?

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This high mount gets some of the prop out of the camera view. For my convenience, the sensor acts as a base to the camera. That is the main reason it is up so high.

BTW, I do not know how linear the sensors will behave if their view is partially blocked by the model. This high mount arrangement would help minimize those sort of MAHI troubles if they exist.

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I have yet to find any bad habits with the MAHI device. It has been very reliable. I'm not into the flying under-the-hood thing, so that sort of test will need to be up to one of the beta testers.

Here is another demo video from a flight this afternoon: MAHI Demo #7.

Edited by Mr.RC-Cam

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I always find it amazing when similar gadgets/ideas are developed by independent folks at the same time. Case in point is this PIC based OSD that I found on the web today. It appears to have been released just recently.

http://perso.wanadoo.fr/ohumez/kapelectron...cs/altiose1.htm

The design is nearly the same as the MAHI, at least as far as the video gen circuitry. It uses a 20Mhz PIC, LM1881 Sync IC, and a few R's and C's. Our two designs are nearly twin sisters!

This design has a lot of cool features, some of which I was thinking about adding to a variant of my design. I'll have to rethink that, since I'm not interested in creating another me-too design. I guess I should have moved my azz faster. ;)

In any event, be sure to check out this other OSD. Looks fabulous.

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In any event, be sure to check out this other OSD. Looks fabulous.

It doesn't have attitude glyphs - so it the same as BOB-2 board from where I am standing... I understand that technical aspect is similar, but it's a closed source as well...

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MAHI board tested.

Here is another happy beta tester report:

1. The board was a pleasure to put together. I have never finished a full blown SMD project before - MAHI board was the first one. It took me 4-5 hours to assemble the board and I rate is a INT difficulty level, if you can change SMD resistor on PT5041N voltage converter to adjust its output voltage - you can build this project.

2. All instructions were clear and the board started to work just as described the moment I hooked up the power biggrin.gif .

3. Set up and adjustment menus are easy to follow.

4. Picture here shows MAHI board sitting on top of Carvec box on my MA gasser:

MAHI_board.jpg

5. Co-pilot sensor is located at the lowest point on helicopter, velcroed to the pull- start:

MAHI_sensor.jpg

Probably not the best place from vibration point of view but I felt that it provides most uniform coverage of horizon.

6. Here is a short video from test flight. You see helicopter is piroetting under Carvec attitude control:

MAHI test video

All settings on MAHI board were default for this flight. During this segment I've only pulled rudder stick to the left. Roll/Pitch stick was centered and Carvec (inertial attitude controller) kept helicopter level. As you can see from visible horizon Carvec is doing descent job, but IR horizon is changing cyclically. I observed similar error in my earlier flights. This IR horizon systematic error or bias will make helicopter slide to one side if I try to allign heli's attitude using co-pilot's AHI indication alone.

On the good side, MAHI response is very quick and I feel I would be able to control helicopter attitude just by looking at MAHI's glyphs (neglecting average IR horizon bias).

7. Overall conclusion:

MAHI project is one of the best little projects I've encountered in the last 2 years. Idea is interesting (using PIC to create video overlay),

performance is good (I can see many people using this gadget for FPV flying),

assembly is not easy but rewarding.

Edited by Mr.RC-Cam

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Thanks for the detailed review and kind comments. I'm especially happy to hear that the MAHI device was not a total bust for you. ;)

And, I really appreciate the demo video -- it helps to see the terrain bias that can occur. The Co-Pilot stabilization system must do some interesting things in that environment. On a heli, would the model try slide off to one side and auger into the ground? If not, what does it try to do?

Another nice thing about your test is that it showed that MAHI can play well with your Telemetry video display device. I was wondering if the markers would be in the way of your data or if the two video overlay systems would interfere with each other. That certainly doesn't seem to be an issue.

With luck we should be hearing from another beta tester soon. In the meantime, I will review the project costs to see what I need to charge for the Board and PIC. It will probably be around $35 USD plus a couple dollars for shipping. But I am not sure.

BTW, is there ANY interest in a fairly complete parts kit? If it helps kick off the project I will do it. I would slightly mark up the component costs, but I have a feeling it would end up being nearly a wash after you factor in the Digi-Key shipping expense. At this point I have enough components for only a couple parts kits, so perhaps that will take care of those that are interested.

Please post here if you expect to take me up on the component offer and I will see if I should proceed with that service.

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Argh, I would still be interested, but are you planning to make a PAL version? We in Europe are looking painfully at that thread ;)

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I would be happy to adapt it to PAL video if there is substantial interest. But, I would like to see how things go for the NTSC version first.

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Another nice thing about your test is that it showed that MAHI can play well with your Telemetry video display device. I was wondering if the markers would be in the way of your data or if the two video overlay systems would interfere with each other. That certainly doesn't seem to be an issue.

Yes, I started to appreciate your idea of putting moving markers on the screen borders. They don't clutter the main view and work well with TL100 board.

I've noticed that my version of AHI (similar to military plane HUD view) is actually distracting me too much.

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