Subject: sending engine data to the PC
From: rotaryeng
Date: 8/27/2012, 11:54 AM
To: AAAA Put this in the To box 


  There are two kinds of serial interfaces in most single chip
 microcomputers. SPI and
  UART/USP.

  SPI is the simpler of the two but it is unsupported in tablets, cell
 phones and PC's
  of all kinds. The so-called "terminal" programs that run in these devices
 requires
  data in ASCII form. There are three different "terminal" programs for my
 wife's Asus
  Transformer tablet alone. Look it up. Unfortunately, I think, Tracy is
 using SPI to
  send data to his EM-2. To get that data into a PC I think would require
 another
  single chipper to reformat the data to ASCII and send it out a RS232 or
 USB interface.

  Now, what I am doing in this EFI design  is converting the binary engine
 parameter
  data to ASCII format in real time and sending that out the RS232/USB.

  Once it is in the PC and saved to a hard disk file it can be read
 directly as a
  spread sheet csv text file. That is a human readable file where the
 numbers are
  separated by commas. AKA "comma delimited file". It then becomes a piece
 of cake to
  write a QB or VB program that displays the file in some sort of a graphic
 form. Or
  one can load it into a spread sheet and let the spread sheet plot the
 data. The late
  great Mistral had all that worked out in their EFI system.

  Here is an example of the data from the Mistral Turbo-Piper crash.
  Be careful with those cheap car mufflers on rotary powered airplane.
  If you have one on there now inspect it with a bore scope (home depot) on
 a regular
  basis.

  Paul Lamar


  Paul,

  Most uC can handle SD [card] interface.

  Pretty simple to have write the data to a SD card, using a FAT16 file
 format.   Pop
  the card out, and use a SD card reader in the PC.

  I'm still thinking of using Ethernet connections due to the electrical
 isolation.
  Solves a lot of issues if you do a data dump between aircraft computers
 and Home PC's.
  1500V isolation is more than adequate, one reason the new SAE diagnostic
 port will be
  Ethernet.

  Tom W

  I don't have a SD card interface in the AT89S2853. (AVR 8051).
  I have one in the ARM. The ARM also has an Ethernet connection.

  I want to display the engine data on the tablet or notebook LCD display
 mounted on
  the instrument panel in real time. When you need it as you are flying
 around. That is
  what Tracy does with the EM-2 but it is very limited display IMHO.

  No pulling out of SD card and plugging it in :) It is simple to use the
 note book
  display as it can run QB or VB and talk to the EFI directly. In QB it is
 real simple
  as you can use the ON COM hardware interrupt but that means you are
 running DOS.
  I have an old Lenova X61 that is either a notebook or a tablet depending
 on how you
  twist around the LCD touch screen. Great for mounting it on the
 instrument panel. It
  has system 7 on it now but it could boot DOS no problem. Of course the
 touch would
  quit working I think. I have installed DOS in the past on old notebook
 computers.
  DOS is the closetet thing to a real time OS with direct hardware access
 as one is
  likely to find. No scheduler.

  I am a simple man :)

  Paul Lamar

 Paul,

 Ethernet buffer management is a nightmare for simple stuff like this.
 Don't go down that route. You have to break down the data into
 packets, keep them in sequence, ack for each packet, do
 re-transmission, etc. then re-assemble them into a single packet. It
 it like re-writing the entire TCP protocol in BASIC, not to be taken
 likely, and forget about assembly for this purpose.

 RS-232 is a current loop interface with build in isolation. Usually
 optical isolation with chips like MAX232. SPI is not appropriate
 because of lack of protection. It is OK to be used within a single
 system. Not if you have many things on different power supply and
 potential sparks from static build up.

 It is really simple to convert byte data into ASCII with Basic. I
 think a simple print statement would do the trick.

 Henry

 Thanks for the tips Henry. I have all the parts ordered and I am about to
 order the
 PC board but I had a better idea for the tach. So the board needs more
 work.

 Paul Lamar


Guys, I think you are making this harder than it needs to be. This board
will read all of your sensors and output them to a tablet, pc or whatever.
It comes ported to Android, but Android is basically Java, and so you can
output it wherever you want. You can also use the touch screen of the
android to control the unit. There are many youtube videos showing using
tablets to turn on lights, dim them, etc from tablets and phones.

http://arduino.cc/en/Main/ArduinoBoardADK

I am going to use this board initially for testing, and have much of the
code written for the EFI now. Depending on the out come of the testing and
the subsequent "load" on the board processor, I may just use 2 of these
back to back for redundancy. I have also considered using the Uno board for
ignition, and let the Mega board read everything else and handle the EFI
and data logging. My first inclination is to use the tablet just for
logging and for display, and keep everything else separate. However, the
program that the Android will use will be resident on the Arduino, so in
theory if your tablet dies in flight you could plug in your phone and keep
going.

I will keep you posted.

Kevin Alderman



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