hamilc

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Why use Open Pilot and Revolution?
« on: December 28, 2017, 06:11:51 pm »
I have been reading about flight controllers on the Internet and trying to find out the best one. Unfortunately, the Revolution and Open Pilot do not seem to be recommended. So, I am wondering, what is the advantage of Open Pilot? Should I consider switching to a different controller and software? I amk just fishing for opinions here.

Re: Why use Open Pilot and Revolution?
« Reply #1 on: December 28, 2017, 07:04:04 pm »
There are many good controllers and many good firmwares available these days.  LibrePilot requires fairly high end hardware and is limited to a smaller set of controllers (but that is expanding in the next version).

LP is the descendant of OP.  The base code is written using more modern techniques such as threads and semaphores rather than one big loop and polling.  That has pluses and minuses when running on limited hardware.

LP currently supports many vehicle types and GPS modes, but GPS is an advanced topic.  Best to learn to walk before you try to run.

There is an active community here at LP and devs are always working on new features.

hamilc

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Re: Why use Open Pilot and Revolution?
« Reply #2 on: December 28, 2017, 10:32:41 pm »
Cliff, do you think the other controllers have as many bells and whistles as LP does?

Is the Revolution a F4 computer? I read about the F numbers going up thru F7 as the performance increases.

Finally for this post, Where are the LED flashes on the Revo listed.? Mine gives a blue flash followed by two yellow flashes when I only have the Revo connected to my computer. After arming the sequence goes to blue then yellow back and forth.

Also the what about the tones and what do they mean?

Mateusz

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Re: Why use Open Pilot and Revolution?
« Reply #3 on: December 28, 2017, 11:07:07 pm »
I have been reading about flight controllers on the Internet and trying to find out the best one. Unfortunately, the Revolution and Open Pilot do not seem to be recommended. So, I am wondering, what is the advantage of Open Pilot? Should I consider switching to a different controller and software? I amk just fishing for opinions here.

Depends what you want to do. You want race or do some autonomous flights ? It seems BetaFlight has more forgiving single loop PID controller, LibrePilot has dual loop PID controller and proper Autotune, which gives perfect PID, so that's I guess a tie. BetaFlight has always stabilized when armed (if you want to do diving and use that feature), LP has that broken in release but fixed in "next" branch if you compile yourself.
Also "next" branch contains more FC hardware supported. BetaFlight does not offer autonomous capabilities, its purely racing stack, LP has many interesting autonomous flight modes.
LP has multiple banks with configs which you can change in flight, no other software does.

I think both BetaFlight and LibrePilot can be flashed onto Revolution board, and I advise you not to listen to people who can often blame firmware for lack of their own knowledge, or there are people who complain about things that are their own fault but they like to blame others. I just can't imagine using different firmware than LP, you hate it or love it. Just try both yourself, that's best, perhaps give feedback to devs if something is missing.

When it comes to hardware F0, F1, F3, F4, F7. Well these are STM32 numbers.

F0 is Cortex M0 core
F1 is Cortex M3 core and little memory
F4 is Cortex M4F core with lots of memory
F3 is Cortex M4F with less memory
F7 is Cortex M7 with caches and lots of memory

there are differences between these MCU, like cache on F7 which is not used, bus matrix how internal peripherals are connected and how you can use DMA, technicals details, but currently we are not using 50% of F4 resources. One could oversample gyro on F4 and use CPU 100% and be stupid, but that would not give any measurable increase in flight performance. F3 core is an interesting MCU as it has built-in inverter on UART and could potentially do FrSky telemetry both ways.

I would suggest Omnibus F3 or F4 flight controller with integrated OSD for racing. LibrePilot will support that soon, its not merged yet but flies very well and can be compiled from dev branch (there is thread on forum how, and maybe someone posted binaries).
If you want to do autonomous flights, I suggest Revolution board or Sparky2.
 

hamilc

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Re: Why use Open Pilot and Revolution?
« Reply #4 on: December 29, 2017, 12:19:01 am »
Mateusz, I rally appreciate the detailed explanation of the controllers. I am a beginner and was just wondering the differences.

I wish I knew enough to be able to download the LP source and compile it myself and perhaps make improvements but I am not that familiar with the software development process.  It seems to be very complicated given the number of options that LP supports. I am learning more and more as I continue to read the documentation and play with my quad.  It seems I am always finding something I do not understand. 

Like I mentioned above, the LED sequences are puzzling. The documentation I see calls out a red and blue led, I have a blue and yellow one. The doc I read shows that sometimes both are illuminated at the same time. I do not see that. It is probably not very important but I am interested anyway.

My quad is ready to fly and I will launch it probably tomorrow.

Mateusz

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Re: Why use Open Pilot and Revolution?
« Reply #5 on: December 29, 2017, 12:47:26 am »
To be honest I never cared to understand these LEDs, I approach them intuitively. I found this old OP archive http://opwiki.readthedocs.io/en/latest/user_manual/revo/leds.html
not sure if this matches current 16.xx version of LibrePilot firmware or where that information is buried on Wiki.

Maybe someone drops in and explains. But my advice would be to connect GCS and look at green squares in Health System panel. If there is Red box there, firmware for safety reasons should prevent arming. You should see reason in tooltip by hovering over that box. You need to fix this, and have all squares green to fly safely or fly at all.

I think it's more important and shows more than LEDs on the board. The only time I cared about LEDs on board was when I was flashing entire chip with SBL boot method (bootloader+firmware image).
But I guess you're not doing that ? Maybe LED behaviour is explained on Wiki in bootloader update page. But don't do that if you dont need to.

hamilc

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Re: Why use Open Pilot and Revolution?
« Reply #6 on: December 29, 2017, 04:46:46 pm »
 I think will pose the LED question on another thread as the LED question is not related to the topic of this thread.

Since I do not have a laptop, I cannot see the system status in the field.  It would be nice if the LEDs would show a general OK status. For example, how would I know if I had good GPS signals?


Mateusz

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Re: Why use Open Pilot and Revolution?
« Reply #7 on: December 29, 2017, 05:27:30 pm »
I think will pose the LED question on another thread as the LED question is not related to the topic of this thread.

Since I do not have a laptop, I cannot see the system status in the field.  It would be nice if the LEDs would show a general OK status. For example, how would I know if I had good GPS signals?

Led is too simple to show GPS signal, also Chinese sometimes install different colors than standard.
I suggest using LP2Go Android application in the field. You just need OPLink and Bluetooth module connected to that OpLink. Than you pair phone with Bluetooth. You should see most important things on the phone.

https://play.google.com/store/apps/details?id=org.librepilot.lp2go.beta
https://librepilot.atlassian.net/wiki/x/BgARAg

Re: Why use Open Pilot and Revolution?
« Reply #8 on: December 29, 2017, 06:48:48 pm »
You can install a simple, cheap WS2812 LED connected to an unused ESC/servo connection.  You get all the warning/error status info from it.

https://librepilot.atlassian.net/wiki/display/LPDOC/Setup+WS281x+Led

Something like this 5 for $1.37 shipped.  You will probably want to solder a servo/ESC connector/wire on it.

https://www.ebay.com/itm/5pcs-WS2812B-5050-RGB-LED-white-black-PCB-Board-1-LED-Module-Pixel-Light/232533913097