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Diyguy

Artificial horizon?

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The AHI is one instrument I would love to see. There have been a couple shown incorporated in telemetry packages, e.g., the Eagle Tree systems data recorder. Could this be used as a real time sytem-like with a Tiny Track, or in an overlay?

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Not to pitch products all the time but AUAV has a low cost artificial horizon that comes up on a laptop with other important infomation such as speed, altitude... www.auav.net

Matt Klarich

AUAV

Autonomous Unmanned Aerial Vehicles

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Would it not be possible to use the information from an FMA-copilot kind of device? You would have to compare the output from the aircraft Rx with the output from the FMA unit. If no Rx command to the servo and no command from the FMA unit, then you are level. Subtracting the Rx command from the FMA command gives you the pitch/roll info. This is a job for a PIC.

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Not to pitch products all the time but AUAV has a low cost artificial horizon that comes up on a laptop with other important infomation such as speed, altitude...

What's the price?

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Would it not be possible to use the information from an FMA-copilot kind of device?

Aboslutely yes. Better yet you need two more sensors (looking up and down) to adjust for absolute value of the IR gradient and then you don't need to calibrate the system every flight.

Tiny Track or MIM-2 are too slow to update frames for efficient AHI display. Faster refresh rates are required. I am looking around trying to figure out what to use to send telemetry data from co-pilot, preferably over audio channel of the Video link. I am kind of convinced that I have to build FSK modem by myself as I don't find anything cheap and small that is suitable for the job.

Regards,

Val.

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Would it not be possible to use the information from an FMA-copilot kind of device?

There was a short discussion about this long ago. I recall that either Dave Thomas or Yb2normal reported that the output servo pulse was proportional to the off-axis error. Should allow useful conversion to an artificial horizon.

My thoughts are that it may be best to start with some IR sensors and build a custom solution. In the end, the amount of work might not be too bad compared to adapting the stock Co-Pilot. If I could find a cheap used Co-Pilot I might try looking into a hack or semi-cloned solution.

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I recall that either Dave Thomas or Yb2normal reported that the output servo pulse was proportional to the off-axis error.

I did measurements of co-pilot's sensor awhile back. Four wires that come out of sensor have:

1. ground

2. +3.3 V

3. roll error analog output (1.65V corresponds to 0 error)

4. pitch error analog ouput (1.65V corresponds to 0 error)

I may be wrong about exact sequence of wires but I am sure what they do.

Melexis IR sensors can be used as direct replacement of co-pilot's sensors but they are not cheap, $15 a piece.

So it's possible to use just a sensor module without uP unit for AIH.

Regards,

Val.

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[Tiny Track or MIM-2 are too slow to update frames for efficient AHI display. Faster refresh rates are required. I am looking around trying to figure out what to use to send telemetry data from co-pilot, preferably over audio channel of the Video link.]

What baud rate do you think would be sufficient for a workable modem?

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Another possibility would be to hack with a Futaba PA1 or 2 (the older PA1 has 2 aileron outputs for 2 servos). I think the PA's use only light and dark rather than, I think, IR on the Co-pilot. I have used them and believe they work quite well-have two of them in planes. You can pick them up for $20-$30 on eBay. I don't know which would be easier to work with, photo or IR. How or what would/could be used for digital display small enough for a model, or is overlay a better solution? The full size guys can get a whole EFIS package displayed on a PDA.

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What baud rate do you think would be sufficient for a workable modem?

9600 bds (4800 minimum). This speed will allow 10-20 data channels to be sent at around 20Hz refresh such as GPS, pressure, electrical and other sensor info.

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Contact Dave Jones at AUAV for information about our artifical horizon system, the system has been designed and tested and can send GPS info as well. I don't have price information, I just program.

email dave-AT-auav.net.

Matt Klarich

AUAV

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The outputs from the Copilot are pretty small signals. FMA incorporated a very low offset dual opamp to significantly amplify and buffer the high inpedence sensor outputs right in the sensing head.

T.I.

Edited by Temporary Insanity

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9600 bds (4800 minimum).

I asked because I had come across a little project that would be perfect except that it is designed for 1200 Baud. It is a cheap, little altimeter with an FSK downlink. A to D/packeting/tone generating done on one PIC16c71. Could serve as a good model by using faster processor and timings. If interested check out http://www.tfs.net/~petek/rockets/altimeter/index.html.

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In the old forums there was someone making one and he said he was going to release it to the public. He even sent a few screen shots that looked promising.

I can't remember who that was... ARE YOU STILL AROUND?

If so, how's the projet going?

If not, are you willing to give us what you have so far for your code so someone else can continue it.

Mike

Edited by mikep

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Am I looking at something very complex or relatively simple. Consider an AHI on a flight sim program. I assume the joystick is sending a voltage or pulse along the X,Y axis that is converted to a graphic representation via the software to show the aircrafts attitude. The Copilot or PA1/2 is providing that same info to a servo via the Rx. If for the sake of discussion, we use a PDA as the graphic presentation-let the video transmit the picture of the AHI-guess you'd have to write a 3D type program depiction of the instrument. What type of circuitry/device would need to be in the middle? Wish I had the smarts to figure this out.

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My idea has always been to use the co-pilot technique to provide a solid reference to horizon where refresh rate was not an issue. I would rely on a gyro in the motion contol loops offset to the calibration value determined from the IR sensors 'not-so-often'.

-matt

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