REFLECTOR: Reflector Digest, Vol 94, Issue 37

Dave T Nelson dtnelson at us.ibm.com
Wed Jan 23 13:43:06 CST 2013


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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