http://www.sparkfun.com/products/11115
A board that has gyros built in- says that the board by itself can be used
as a 3 axis controller.
Vibration resistant enough for a model RC helo. If they can stand that much
vibration, they have to be tough.
What do you think?
Kevin Alderman
We had a big discussion about this a while back. Gyros are built into some
cell
phones and tablets. There is some software for the tablets that use SS
gyros to give
the pilot synthetic vision.
Paul Lamar
I ordered a board, and after I play with it for a bit I will try to build a
3 axis autopilot. The board also has provisions to mount a GPS chip. My
boat has NMEA 2000 GPS signal output, and a simple hydraulic motor drive
steering. I can outfit the boat with the system by interfacing the motor
drives from the unit to the steering pump. I will try to slave the unit to
the output of the built in GPS, and compare the board GPS chip performance
to the built in GPS. The advertisements said that the software for an
autopilot was already available for download, which should give a good
starting point and save a lot of time.
I will try it on my boat first, if it can navigate the boat at 12 knots in
6 foot seas for 12 hours, it should work in the plane if it can update fast
enough.
Just a thought- after reading over the info, this system with an on board
GPS chip can be programmed with a destination, degree of rotation limits, G
limits, and using tables on an SD card, a flight profile. Meaning for
around $300.00 for board, chips, and 3 servos, I can program my plane to
take off, fly somewhere and "land" within a few feet of its target. It is
unlikely that I would get to use the plane again.
I will let you guys fill in the blanks regarding the implications.
Kevin Alderman
I did some work on reading a GPS back in 1990. Here is my Kitplanes article.
I'll send some of the info on the NEMA 0183 interface as soon as I find it.
--------------------------------------------------------------------------
If you are running XP Quick Basic in a computer with an RS232 interface these
programs will run in a DOS window. Old computers with DOS or XP are pretty cheap.
Make sure they have an RS232 interface. I just bought one from Geeks.com with XP
installed. http://www.geeks.com/products.asp?cat=SYS
Unzip the QB language (attached) and you don't need to install it as all you do is
type "QB" in the DOS window command line. QB was the easiest way to write program
ever IMHO. It has never been bested.
In that case this these GPS programs will work.
OPEN "sat.dat" FOR OUTPUT AS #3 'open HD file #3 called "sat.dat"
CLS
OPEN "COM1:4800,N,8,2,OP15000,RS,RB32000,CD0,DS0,CS0" FOR RANDOM AS #1
PRINT #1, "$PLWRO"
ON TIMER(120) GOSUB doit2 'data coming in
TIMER ON
start2: 'sit in this loop until the data comes in from the GPS
IF INKEY$ = CHR$(27) THEN GOTO enditall 'somebody pressed the esc key
GOTO start2
enditall:
CLS 0
FOR del1 = 1 TO 100: NEXT del1
CLS 0
CLS
CLOSE
END
doit2: 'sub routine
x = x + 1
TIMER STOP
temp$ = INPUT$(LOC(1), #1)
OPEN "temp1" FOR OUTPUT AS #2 'open a HD #2 file name for the data
PRINT #2, temp$
CLOSE 2
OPEN "temp1" FOR INPUT AS #2
DO WHILE NOT EOF(2) 'keep checking for the GPRMC sentence
LINE INPUT #2, temp$
IF MID$(temp$, 1, 6) = "$GPRMC" THEN GOSUB gotit
LOOP
CLOSE 2 'close file 2
TIMER ON
PRINT #1, "$GPRMC"
RETURN
gotit: 'subroutine
PRINT #3, x;
PRINT #3, temp$
RETURN
http://www.gpsinformation.org/dale/nmea.htm
$GPRMC,123519,A,4807.038,N,01131.000,E,022.4,084.4,230394,003.1,W*6A
Where:
RMC Recommended Minimum sentence C
123519 Fix taken at 12:35:19 UTC 'to the nearest second
A Status A=active or V=Void.
4807.038,N Latitude 48 deg 07.038' N
01131.000,E Longitude 11 deg 31.000' E
022.4 Speed over the ground in knots
084.4 Track angle in degrees True
230394 Date - 23rd of March 1994
003.1,W Magnetic Variation
*6A The checksum data, always begins with *
There is probably an equivalent in Visual Basic using a USB port. When I get that
working I will up load that.
You can used the GPS track angle to control the heading in your auto pilot.
Any heading gyro is going to drift. Same for the pitch gyro. OK for short term but
you should check barometric altitude.
The altitude data from the GPS is not good enough so you will need the $15 barometric
pressure sensor from FreeScale like Tracy uses in his EFI.
Paul Lamar
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