# EFIS For Homebuilt / Experimental Aircraft.

Discussion in 'Instruments / Avionics / Electrical System' started by JMillar, Apr 11, 2008.

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1. Apr 11, 2008

### JMillar

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I love the look and functionality of a 8 inch or so screen displaying navigation and engine information. Advanced Flight systems has a setup like that listed for several thousand dollars, but then you have to upgrade it with sensors, etc. There are some others also, from Garmin down (price wise)

So, how about taking a barebones computer (probably a laptop for light weight), stripping of all unnecessary brackets, case, etc., and basing a EFIS around that?

• Use a remote (add-on) screen, preferably a touchpanel, mounted on the panel, with the existing screen (in the case of the laptop) disconnected entirely.
• Remove the hard drive, boot from flash and run from RAM, saving all data to a (separate from the boot disk) flash card.
• Run the system off filtered alternator / battery power, with its own internal backup.
• Use a cheap USB or serial GPS system (even most cheap ones support WAAS now) – Garmin sells good ones under 100.
• A PIC or AVR microcontroller, again interfacing thru RS232 or UPS has enough channels to digitize data from engine sensors, a pressure transducer for altimeter, accelerometer for G-meter, etc
• Should be a XM-radio module that can get weather information.
• Decent graphics card would mean that adding a second screen is trivial

Do you think that you'd end up saving money over a equivalent commercial system? I think it would. Might end up close to the cost of fairly cheap unit, but with significant features, not to mention ease of adding features as needed. One would have to put a lot of time into it, but aren't homebuilders already all right with that?

2. Apr 11, 2008

### Jman

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I have wondered along the same lines. My thoughts were that a tablet PC could mount in a shock stabilized docking station arrangement in the instrument panel. You could pop it out after the flight and use it as a trip planner to plan the next flight and configure the software. Heck, it could even display an in-flight movie for the passenger(s) if you wanted it to.

I have no illusions that it would be as stable as a purpose built set-up, but it could work. In fact, I think I remember reading that Burt Rutan's boomerang design did not use a traditional instrument panel but used laptop computers.

It's not EFIS but an interesting product was mentioned by Orion about a year ago that can be used with a tablet PC. Here is the link.

3. Apr 11, 2008

### rtfm

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Hi guys,
I'm one of the first to put my hands up when it comes to endorsing a small-guy effort, but I think we need to temper the urge to innovate (or at least, to emulate) with a healthy dose of reality.

And the reality is (in my opinion) that you and I just can't do as good a job as the people who live and breathe and infuse themselves with this technology can. I'm in the computer industry, and into programming in particular. I could write software which would do what you have suggested. But I also know that it would take me an age to debug it, and to enhance it and to do everything that needs to be done in order for someone to trust their lives to it.

I guess it is very much like converting a car engine for aircraft use as opposed to buying a ready-engineered aircraft engine. Spend the money, bite the bullet and do it right. And sleep easy.

Regards,
Duncan

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4. Apr 11, 2008

### Jman

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I read a couple of days ago, on another forum, that there are over 1 million lines of code in the MGL line of EFIS systems and they are only adding more as the features continue to expand.

I guess it depends on what you are relying on the system to do for you. I think it would be foolish to use such a system as your sole navigation or instrumentation, especially in situations that were less than full VMC conditions. But, for Day VFR experimentation and recreation, I would not lose any sleep over trying something new and untested. I think being able to make a system like that work would be very enjoyable and a good challenge for some people. It's one of the big reasons I think this sport is so darn exciting.

However, if your goal is to get exactly what you would get from a purpose-built aviation grade EFIS in reliability and functions, but only cheaper.....I don't think that would be a realistic goal. But, I'm not an engineer, just a pilot who flys a outdated EFIS every day. So take my opions with a grain of salt...<grin>

5. Apr 11, 2008

### Dana

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I suspect what you're describing would cost a lot more than the "several thousand" JMillar mentions. Also stripping apart a laptop isn't a simple proposition, let alone reassembling it with other components. If you really wanted to go that route, there are a couple of outfits making micro desktop computers based on laptop components (with external power supply so they'd run on 12VDC). I do industrial automation for a living, and my latest machine was controlled by one of those in conjunction with a 26" touchscreen (actually the machine was controlled by an industrial PLC, with the Windows PC only an operator interface). There's some industrial software out there that would make the programming relatively easy. But as Jake suggests, a tablet PC would probably be a better choice... and a fun project for a hobbyist, but not a truly cost effective solution.

Some of the glider guys are using a PDA with GPS and assorted sensors, though it's a rather small screen.

But check out PCEFIS.

-Dana

A rolling stone .... kills worms.

6. Apr 11, 2008

### JMillar

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Ok, Dana is right about the micro-desktop being a good fit for the system. The reason I was thinking laptops is, I've often been able to get really good deals on dead-screen laptops, because no one wants to spend the money replacing it. Then a bit of refurbishment, and it's a decent desktop once you add a real mouse and keyboard. In this case, you strip it, and add whatever interface you need.

They are a pain to take apart and re-assemble, but nothing a competent amateur can't handle. You just have to be really delicate, and keep good notes. I used to fix all kinds of that sort of thing, for spending money. Cell phones are the worst.

That's it exactly. Doesn't substitute for your basic instrumentation, just decreases navigation workload and increases the "cool factor" ... while it's working. As Duncan says, I certainly wouldn't try to write all the software for it, that could take a lifetime with my programming skills, (a short lifetime with my pilot skills!) I would want to re-use existing nav software and write my own stuff to do instrument overlay on the nav screen. If I find a nav package that would deal with it, Real Time Linux would be the ideal platform. I've dealt with it in a minor way before to run machines, but not enough to call myself competent.

Digikey stocks sensors, including a very nice dual axis clinometer + accelerometer in one package, and a barometric-range pressure sensor. Don't have part numbers handy because I'm typing this on my lunch break at work. They also have all the other sensors you could ever need in terms of temp, oil pressure, etc. Programming a AVR or PIC to report outputs from those would be trivial for an expert, which I'm not, but have access to.

The screens available for seatback DVD players in SUVs might be a good start for the display. They're already 12 volts. Maybe buy cosmetic rejects or something, since the bodywork into the panel would be custom. Cnet.com used to (maybe still do) have showcases of people doing this with their cars - built-in computers with navigation and stereo control, stuff like that. They have more freedom with space and weight.

Obviously I should get my plane going before I get too serious with this - but I'd like to know what hardware I should plan for. This might be completely ridiculous in a KR2 (what I'm still leaning towards) but still... fun.

Edit: Oh, and... what sort of gyro sensor do I want for turn rate?

Last edited: Apr 11, 2008
7. Apr 11, 2008

### Topaz

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Yep, these are becoming very common. Full flight logging, terrain avoidance, weather, etc. All runs on the PDA's own batteries, since most gliders don't have an electrical system.

Here's one that's fairly common.

Guys, no need to re-invent the wheel. Examples such as the PC-EFIS Dana lists above do everything you're talking about (including linking to a gyro module), and run on existing hardware. One of the options for the unit is an external 1024x768 sunlight-readable display. The basic module is only $895. Here's another one that I personally really like. It already runs on a Windows Tablet PC (or PDA) - if you like gee-whiz factor, this one's got it. That's a synthetic vision display at the top of the window - with the terrain color-coded by proximity to your altitude. There are modules you can buy that will overlay realtime weather, gyro input to drive the 'windshield' synthetic vision display as an attitude indicator, and more. The software is$495, so if you pick up either a gutsy PDA or one of the cheaper tablet PC's you'd have a system with some pretty substantial capabilities for a lot less than the cost of a dedicated EFIS system - and you won't have to do any programming.

8. Apr 11, 2008

### Midniteoyl

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Forget 'micro'.. go 'pico' : http://www.via.com.tw/en/initiatives/spearhead/pico-itx/index.jsp

10cm x 7cm and all the power you need.. These things run Windows, WinCE, Tablet PC, Linux, you name it. One could put already made software on it such as mentioned above.

Motherboards based on this design pre-made are known as the EPIA series..
http://www.via.com.tw/en/products/mainboards/motherboards.jsp?motherboard_id=472

Or, you can buy a complete kit to do what you want: http://www.via.com.tw/en/products/embedded/artigo/index.jsp

Last edited: Apr 11, 2008
9. Apr 11, 2008

### Topaz

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No... Power... Supply... In.... Glider.... :roll:

You power guys have all the luck on things like this.

Very, Very, Very cool, however!

10. Apr 11, 2008

### Midniteoyl

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11. Apr 11, 2008

### PTAirco

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Skin those giant wings in solar panels and you'll have all the power you need!

12. Apr 11, 2008

### bmcj

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Excellent point, especially for the electronics hobbyist.

Bruce

13. Apr 11, 2008

### JMillar

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Ok, I've cut my goals back somewhat, or modified them, or whatever. I now like the idea of, still taking a miniaturized PC or laptop, and integrating an external screen into my dash. Then I run mainly existing software on it, adding on in small increments whatever is lacking in terms of sensors and features.

Does anyone know anything about GPS / nav software under linux? I'm looking at a few options, but nothing seems to be adequate *and* mature.

14. Apr 11, 2008

### Rhino

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15. Apr 13, 2008

### Waiter

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I'm sure you've seen it before, but I'll post it again.

This software currently interfaces with Dynon, Grand Rapids, and standard (and special Garmin) serial outputs.

http://www.iflyez.com/EFISRecorder.shtml

Send me a serial format for your EFIS and I'll modify the program so it can acceft the inputs.

Waiter

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16. Apr 13, 2008

### JMillar

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Wow, Waiter. I'm almost as impressed with the software as with the airplane. Now, if I could couple that with a moving-map package, it would be the perfect setup. Should be do-able.

I guess it's time to set myself up a Windows computer and play with all this stuff. No one seems to want to bother with Linux for these kinds of applications. Ah well. Soon, I'll order some sensors and see if I can get a AVR sending the output thru serial to a computer.

17. Apr 29, 2008

### JMillar

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Well, I've just found out the race ended before I got there. JStock posted a link to a site on Soobs, where I also found this: http://www.maddyhome.com/canardpages/pages/alwick/index_files/Page575.htm

It's about a "glass cockpit" system self-designed by this guy... it uses off-the-shelf sensors and interface, and he sells the software (which you can modify yourself) for \$40!

It's just sensors relating to engine / fuel / gear / etc, no navigation, as far as I can tell, but if you add that to a moving-map software package in another window, you're set.

18. Jul 29, 2016

### ninelima

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I have been working on something for the standard Android devices. I named it kwik EFIS.

The results are very dependent on the device used though. Quad Core devices with suitable sensors like the Nexus 7 work OK. Also tested om om some of the later model Samsung devices.

For more information and details on how to install the app, see:
http://members.iinet.net.au/~ninelima/efis/index.html

19. Aug 1, 2016

### Bill-Higdon

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In my opinion, you need to includes support for a Pitot Static system Like Open Soar and some of the others including all of the "name brands" do

20. Mar 18, 2017

### ninelima

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I am pleased to announce that Kwik EFIS has been accredited and accepted as Free and Open-Source software (FOSS) by F-Droid.

Thus, the Kwik EFIS package will now also be available from the F-Droid catalogue at:
https://f-droid.org/repository/browse/?fdfilter=kwik&fdid=player.efis.pfd

The current released version is 2.4. It features the portrait mode and the HITS navigation display.

Changelog
=========
2.4 (2014-03-17)
------------------
* Waypoint database cycle 2017-03 (usa.can)
* Change bank/skid correction filter constant
* Add automatic de-clutter to HITS

Users may want to install the F-Droid catalogue application as well. It provides a most excellent Free Software portal similar to the Google Play Store.

F-Droid provide easy access to a variety of great FOSS software and a easy mechanism updating your installed apps.
See: https://f-droid.org/