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Anyone experiment with electronics / avionics?

DCat22

DCat22

Well Known Member
Just noticed this inexpensive 9dof AHRS board available from Sparkfun (3 gryo, 3 accel, mag): http://www.sparkfun.com/commerce/product_info.php?products_id=9623

Along with open source code: http://code.google.com/p/sf9domahrs/

I'm not exactly planning to make my own avionics for an RV, but I experiment with RC control and autonomous stuff on a limited/small scale. Flying this stuff up sitting in a "real" plane is a good way to test it though.

Once I have a flying plane, was planning to have one screen as a PC (secondary/tertiary to the main avionics) which could be interesting to experiment with as well, since it would be easy to pull in data from temporary/test sensors. (ie. Maybe something that would record and visualize an acro routine?)

Anyway -- just a curious general question if any folks have delved into this area of "experimental" -- mainly for the fun of it? I know it's faster/easier/etc to buy the fine commercial products out there for your main systems.

09623-04_i_ma.jpg
 
Cool unit.

Combine that unit with a very cool open source flight emulator (flightgear.org) and you could easily build a nice EFIS. I had started on a similar project a few years ago, but let it slide when then MGL Enigma debuted.

The key, of course, is integrating all the components smoothly, as well as stabilizing the adhrs unit. It's "non-trivial". :_)

DCat22 said:
Just noticed this inexpensive 9dof AHRS board available from Sparkfun (3 gryo, 3 accel, mag): http://www.sparkfun.com/commerce/product_info.php?products_id=9623

Along with open source code: http://code.google.com/p/sf9domahrs/

I'm not exactly planning to make my own avionics for an RV, but I experiment with RC control and autonomous stuff on a limited/small scale. Flying this stuff up sitting in a "real" plane is a good way to test it though.

Once I have a flying plane, was planning to have one screen as a PC (secondary/tertiary to the main avionics) which could be interesting to experiment with as well, since it would be easy to pull in data from temporary/test sensors. (ie. Maybe something that would record and visualize an acro routine?)

Anyway -- just a curious general question if any folks have delved into this area of "experimental" -- mainly for the fun of it? I know it's faster/easier/etc to buy the fine commercial products out there for your main systems.

09623-04_i_ma.jpg
Click to expand...
 
I did. Someday I'll post photos, but I made a little 4 line LCD thing that fits in a 3 1/8" hole on my panel. I used an Atmel microcontroller and it does the following things:

* Display trim position
* Reads fuel data from my GRT box
* Outputs fuel datamy Garmin GPS 430 (diffrent protocol from my GRT)
* Change trim speed based on airspeed (from the dynon air data) - just changes a voltage divider, so the actual trim controls are just regular relays and don't depend on a microprocessor

Been working great for 300+ hrs.
 
N131RV said:
Combine that unit with a very cool open source flight emulator (flightgear.org) and you could easily build a nice EFIS. I had started on a similar project a few years ago, but let it slide when then MGL Enigma debuted.

The key, of course, is integrating all the components smoothly, as well as stabilizing the adhrs unit. It's "non-trivial". :_)
Click to expand...

I was vaguely considering doing more before I saw the MGL (and Vertical Power) stuff... :)

kevinh said:
I did. Someday I'll post photos, but I made a little 4 line LCD thing that fits in a 3 1/8" hole on my panel. I used an Atmel microcontroller and it does the following things:
Click to expand...

Found a pic of it from you sig links, I believe. Nice!
 
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I've been working with the sparkfun 6dof v4 at work. We have 6 of them, and I haven't been very impressed with the quality of the boards. Some of the chips are slightly out of alignment, probably from their reflow process. For the inertial sensors, this translates to the axis' being slightly out of sync. The magnetometers aren't amplified properly, so the output only changes a few percent during a 360 degree rotation. With the 10-bit ADC that's not enough precision to come up with a good compass heading.

Hopefully the newer units are better.
 
Here is a link to a guy that took homebuilt avionics to the extreme:
http://www.s5tech.net/s53mv/avionics/avionics.html

The cliff notes version is that this guy built a DME, GPS receiver, multiple VOR receivers (including one with a localizer), a Mode A/C transponder, TCAS, and a bunch of other stuff from scratch. He has uploaded his schematics and drawings for anyone interested.
 
Wow, awesome stuff all around. (Even built his own radar altimeters and TCAS!)

(Thanks for the Sparkfun info as well...haven't used their board stuff. I'll probably try that 9dof board for an RC project, so I'll let you know what I find.)
 
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Autothrottle

I've been playing around with some of my old industrial automation hardware with an eye toward creating automatic controls for the throttle/prop/mix. Not for shooting 0/0 approaches with the autopilot, but for optimizing performance in enroute flight. The system would pull engine parameters from the EMS and make small corrections to optimize engine operation.

Using similar hardware, I think I'm going to build a trim servo for the RV that works more like the systems in certified aircraft - it'll drive the manual trim. That way, for stick and rudder flying, you can still have the feel of a mechanical trim, without losing the benefits of autotrim in IFR flight. On the electronics side of things, I'll have to come up with a motor drive and an interface to an autotrim module for my TT autopilot.

Matthew
 
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