REFLECTOR: Reflector Digest, Vol 94, Issue 37

Wed Jan 23 16:01:22 CST 2013

Hi Dave,

I'm sorry I didn't make myself clear. I was going on the premise of building your own because the topic had mentioned building a single PCB computer to do what you needed. My comment was on how Avidyne handled it with the information from the Garmin and it was something that if you were thinking of designing on your own could give you some ideas on how to implement it. And I should add if you did build it, I would be happy to take one off your hands. ;)

Richard 

Sent from my iPhone 5

On Jan 23, 2013, at 2:43 PM, Dave T Nelson <dtnelson at us.ibm.com> wrote:

> I'll respond to Rich Ervin and Rich Gentil below...
> 
> From:
> ----- Message from Rich Ervin <rich_ervin at hotmail.com> on Wed, 23 Jan 2013 13:54:25 -0500 -----
> 
> To:
> <reflector at tvbf.org>
> Subject:
> Re: REFLECTOR: Need a topic... gear down check
> Any way to build this based on altitude or distance to ground? Some simple range detecting device that can measure the distance to the ground?
> 
> What I'm planning is to use the Dynon altitude (referenced to MSL), and subtract the altitude of the destination airport (using the three letter identifier and a quick database look up)... to approximate the AGL altitude.  This is far from perfect... I've looked at trying to find an elevation database I could use and reference via lat/long... but so far no luck.  
> 
> From:
> ----- Message from "Richard J. Gentil" <richard at naples-air-center.com> on Wed, 23 Jan 2013 14:22:12 -0500 -----
> To:
> Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Subject:
> Re: REFLECTOR: Need a topic... gear down check
> Rich,
> 
> You could use a radar altimeter. Also the Avidyne System in the Cirrus uses the GPS to give you TAWS terrain warnings when you are more then 5 miles from an airport and it calls out 500ft when you are on approach before landing at an airport. 
> 
> I would think that something like that would be what you are looking for in order to integrate with a gear warning if the gear is still up. 
> 
> Richard 
> 
> I've actually looked at homebrew radar altimeters for this application... complicated and expensive.  The Avidyne system in a Cirrus is quite different from my Garmin GNS-530W... my Garmin has terrain warnings, but unfortunately does not output anything usable regarding terrain warning or AGL altitude in the RS-232 data string.  As I'm not ready to by an Avidyne (or a Cirrus), I'm kinda out of luck on that front and working on my own solution.
> 
> To all - thanks for the input!
> 
>   
> Dave
> 
> Dave T. Nelson
> T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
> Program Director, ISC ECAT NPI & Test Engineering
> 
> 
> 
> To: reflector at tvbf.org
> From: dtnelson at us.ibm.com
> Date: Wed, 23 Jan 2013 10:56:02 -0600
> Subject: REFLECTOR: Need a topic... gear down check
> 
> OK, because the reflector is quiet, I'll bring the team up to speed on a little side project I've got going & again ask for any input...
> 
> I've never been happy with the gear up warning system... I like to fly a tight pattern, and often times I won't have the throttle fully cut off until I'm right over the numbers.  A warning system based on throttle position therefore doesn't give much warning.  So, since winters are long here in Minnesota, I dreamed up a really complicated but maybe better solution.  
> 
> In net, I'm working on programming for a very small (think size of a pack of cigarettes) and very cheap ($35) Single Board Computer, which will be interfaced to watch the various gear position microswitches.  It also is taking the RS-232 serial data stream from my Dynon D10-A and my Garmin GNS 530W as inputs to set up the following test...
> 
> If I am within, say, 3 miles of my GPS destination, and
> if I am going less than 120 knots (maximum gear extension speed), and
> if I am less than say, 300 feet AGL, and
> if my gear is NOT extended.... THEN
> My wife Ali's voice will come over the intercom, loud and clear, saying "PUT YOUR GEAR DOWN, STUPID!  YOU'RE ABOUT TO CRASH!!!"
> 
> What dya all think?  Pretty cool if I can get it to work!
> 
> I'm using a SBC called a Raspberry Pi... it's got a 700 mhz processor, 512 MB of onboard RAM, two USB ports, audio and HDMI outputs, an onboard ethernet port, and an onboard SDRAM slot.... all for $35 (!).  I've got the interface electronics worked out (buffers, voltage shifters, a MUX for the two RS-232 serial data streams, etc.), and I'm working on the programming.  
> 
> Obviously, this is pretty much a "one of" implementation, since it's dependant on my Dynon and Garmin panel.  If it all works as planned, though, it should be just a SMOP (Simple Matter Of Programming) to adopt it to other panels. 
> 
> Any thoughts out there?  What else could I use it for, like other warning systems?
>  
> Dave
> 
> Dave T. Nelson
> T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
> Program Director, ISC ECAT NPI & Test Engineering
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