Hi Terry Im interested in rolling my own flap and trim control. Are
you willing to share your setup and code design.

Steve Izett



Steve, what board are you planning to use? I have a program that I
wrote for an Arduino Mega that reads a POT connected to the flap
actuator and activates an H bridge. It works- press the down button
and get 10 degrees, press it again get 20 and the third time get max,
which on my plane is 40. Press it once and it goes up a notch, etc. I
have tried to put it on an Uno or Tiny and it doesn't work just
right, but on the Mega 2560 it works fine.

I re-purposed a pair of Microsoft joysticks for my sticks- the center
joystick is elevator and aileron trim, the buttons on the left are up
and down flaps, and the buttons on the right are interior lighting.
The thumb button is autopilot off and on. The trigger is PTT. Works
great.

If anybody wants more info, shout at me.

Let me know if this will work for you-

Kevin Alderman


Hi Kevin Thanks for the feedback. I’m using the Colour Maximite
which used interpreted basic script. Your flap control is similar to
what I plan to do. A few lines of code with a pot as feedback. I’m
interested in automating the pitch trim and wondering whether air
speed, flap position and weight and balance will be consistent data
to reliably adjust trim, or will it require feedback from the
autopilot system? If it requires data from the skyview bus then that
  puts it beyond my time/ability/risk decision matrix.

Cheers

Steve Izett

https://www.kickstarter.com/projects/818225433/maximite-bbx-the-modern-day-basic-language-compute





<https://www.kickstarter.com/projects/818225433/maximite-bbx-the-modern-day-basic-language-compute

Wow! That is really cool Steve. I got to get one and try it out.

Looks like I can port my GPS driven Moving Map software I wrote in
1990.

Finally one can write real time software on this jewel.

Paul Lamar

Not sure I would try to couple trim to the A/P. The A/P is always
making minute adjustments as it flies, and to add another variable
to the system such as an automatically adjusting pitch trim might
cause an oscillation issue. Also, I can see the system being able to
adjust for burned fuel if you have a totalizer, but any other
adjustments would require in depth programming.

I plan to measure the pressure i.e output at the pitot static lines
connected to a pressure sensor so I can equate the pressure to
airspeed. I can also connect a pressure system to an airspeed
indicator at my desk as well- might be safer. I will then use this
to correlate the flap deployment speeds into the program so that you
can only get 10 deg of flaps 110, 20 at 100, and 40 at 80. I also
have incorporated a sort of failsafe to raise the flaps at any
indication of full throttle- like a missed approach. The flaps will
retract at first quickly from 40 to 20, then slowly to 0 as airspeed
increases. In low visibility conditions like an IFR approach the
flaps would be one less thing to worry about.

Kevin Alderman


Hi Kevin

Thanks for the thinking. Get the feedback path between auto and auto
trim. Yes, could oscillate. Appreciated Steve Izett

Steve, what is the part number on that main chip in the Maximite?

What is the operating system like? Can you save and load files?

Paul Lamar

Paul
See attached schematic.
PIC32MX695F512L-80I/PF or the PIC32MX795F512L-80I/PF (includes a CAN interface)
Operating system is fine - just think TRS80 or Commodore64 just a whole lot faster.
MMBasic is derived from Microsoft basic, but more powerful with lots of direct hardware drivers embedded in the language.
At startup it will run the “autorun.bas” if present on the SDCARD (drive B:) or internal to PIC32 (drive A:) If no autorun.bas then system sits waiting for commands at prompt.
Load “enginemonitor.bas” - Run…..

Geoff has added - hardware interrupts, watchdog, read period or freq signal on pins. etc etc etc.
Get this. Connect the I2C between a Maximite (master) and a Micromite (slave) and just a few lines of code and the Micromite turns into a port extender for the Master.
Having said that the Maximite has 40 ports.
Read the MMBasic Language Manual DOWNLOAD <http://geoffg.net/Downloads/Maximite/MMBasic%20Language%20Manual.pdf
Just to easy and cool.

Steve

Thanks Steve. I am heavy into researching this thing. I think it would
make a great combo EFI/EFIS.

I am interested in running MMBasic on this board.
I like it because all ports are on it.

BTW I don't think the Maximite has enough RAM to run my moving
map software.

Paul Like