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Apr 15, 2009, 01:27 PM
David1
bmw330i's Avatar
Quote:
Originally Posted by danstah
So heres a question. Anton and i discussed implementing a yaw controller since i have an imu at hand... From what i am reading i would still want to couple the ailerons and rudder or would that make it not possible?
Actually it depends how quickly you want to turn and the attitude you wish. High rate of turn I'd use only aileron/elevator, slow flat turn lots of rudder with some aileron and a little elevator.

I suppose negative stability helps the aileron/elevator (elevon for a FunJet) turn. You can bank then just use only elevator. High-wing or planes with dihedral will force you to keep giving aileron as the plane will naturally try and go back to level. Try this in a flight simulator and you'll see the difference. Pick a FunJet or flat wing and then a Cessna172 high-wing.

Interesting thoughts though as now I'm curious how the Paparazzi code commands a turn. The logic and Math to turn and hold the turn, holding altitude etc...
Last edited by bmw330i; Apr 15, 2009 at 01:30 PM. Reason: fixing a logic error
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Apr 15, 2009, 05:08 PM
Registered User

Connecting Paparazzi standalone GPS to U-center


Hi everybody,

we recently started with a TWOG bundle from PPZUAV. Until now, everything seems feasible but out of curiosity I was wondering how to connect the GPS v1.3 with LEA-5H chipset to the u-center. I gathered information from posts #1133 and #1134 in this thread, the wiki and the ublox manual but still I don't have clear understanding, very possibly resulting from limited knowledge in electronics.

I do understand that I cannot take the serial signals directly into the serial port of the PC because the latter can provide voltages >5V and that I can avoid this by using the level shifter or a FTDI USB-TTL cable to go into the USB port.

Not having this adapter, Couldn't I just use the USB-D+ and USB-D- pins of the 8-pin connector and connect them to the computer's USB-port directly? The 5V maximum supply voltage should be provided by it. According to post #1134 this doesn't seem to be the usual way and I don't understand neither why the wiki recommends to connect GND and +3,3V on the GPS connector nor bmw330i's soldering instructions. Thanks for your help!

Cheers,
joachim
Apr 15, 2009, 09:00 PM
David1
bmw330i's Avatar
Quote:
Originally Posted by joachim
Hi everybody,

we recently started with a TWOG bundle from PPZUAV. Until now, everything seems feasible but out of curiosity I was wondering how to connect the GPS v1.3 with LEA-5H chipset to the u-center. I gathered information from posts #1133 and #1134 in this thread, the wiki and the ublox manual but still I don't have clear understanding, very possibly resulting from limited knowledge in electronics.

I do understand that I cannot take the serial signals directly into the serial port of the PC because the latter can provide voltages >5V and that I can avoid this by using the level shifter or a FTDI USB-TTL cable to go into the USB port.

Not having this adapter, Couldn't I just use the USB-D+ and USB-D- pins of the 8-pin connector and connect them to the computer's USB-port directly? The 5V maximum supply voltage should be provided by it. According to post #1134 this doesn't seem to be the usual way and I don't understand neither why the wiki recommends to connect GND and +3,3V on the GPS connector nor bmw330i's soldering instructions. Thanks for your help!

Cheers,
joachim
Hello,
You would need a special cable like the one I built to program them with the firmware and Paparazzi config. Is there some reason you must connect it to u-center?
If so you need an 8-pin molex a voltage regulator so you can give the board exactly 5 volts. I can take a photo of the cable I made myself.
There are no shortcuts really to get around connecting things up and using the paparazzi GUI and GCS (Ground control station) to view the information.
-David
Apr 18, 2009, 10:45 AM
IAD
IAD
UAV Driver
IAD's Avatar
A couple questions for TWOG + GPS 1.3 (LEA-5H) users... (There are some out there, right?)

First, how long does it take to get lock? I got the first lock after 30 minutes (normal enough), shut it down for a couple minutes, tried to do a warm start, and 20 minutes later still didn't have a lock... Tried cycling the power a couple times... This is outside, with a clear view of the sky. My LEA-4P Tiny 2.11 would get a warm start lock after a minute or two, tops..?

Second, I just tried to do a cold start (hit the button in the GCS) and now it's not doing anything, the Paparazzi Center is telling me "Invalid_argument("Latlong.of_utm")?
My best guess is that the "last good" coordinate the GPS has in memory is corrupted, but why did doing a cold start do that?

Any thoughts? I do have the -DGPS_USE_LATLONG in the airframe config. file...

Edit: I've just verified that it is a reproducible issue... If I remove the USE_LATLONG from the config. file, allow it to get a lock, then put it back, and do a cold start, the "Invalid_Argument" message comes up, and I have to go back to non-USE_LATLONG to reset it.

Edit-edit: Alternatively, I wait until it obtains a lock, which is now quite quick... Then the "Invalid_Argument" message goes away, the GCS finishes booting, and all is well. But, if there's a fix for this, I'd be interested, since until the GPS has a lock, I can't do anything in the GCS. (It behaves as though the datalink isn't running.)

~Luke
Last edited by IAD; Apr 18, 2009 at 11:45 AM.
Apr 18, 2009, 07:32 PM
Registered User
IAD,
it sounds like the configuration file on your GPS receiver is messed up. You should hook it up to U Center and take a look.

AJ
Apr 18, 2009, 09:07 PM
David1
bmw330i's Avatar
Quote:
Originally Posted by AntonK
IAD,
it sounds like the configuration file on your GPS receiver is messed up. You should hook it up to U Center and take a look.

AJ
Maybe the CAP on the board is keeping a bad storage value in the module? Daniel has gotten pretty good with the GPS boards/modules.
Apr 18, 2009, 09:53 PM
Registered User

Will PPM Encoder work with Futaba 7C FASST 2.4Ghz radio?


Hi Hendrix and others:

Does anyone know whether PPM Encoder will work with Futaba 7C FASST 2.4 Ghz radio? In Futaba 7C, only channel 3 (throttle) can be set into fail safe mode. The 3-position switch G for "Mode" is on channel 7 with no way to set the fail safe mode (I guess that the receiver will hold its last valid signal value for channel 7 in case the RF signal is lost).

Has anyone had actual success in using this radio personally?

Thanks.
Last edited by SteveRoss; Apr 19, 2009 at 12:52 PM.
Apr 18, 2009, 10:34 PM
IAD
IAD
UAV Driver
IAD's Avatar
Ok, I have checked the config, it looks good, but I'll take another look, maybe I missed something. However, the slow locks went away... It's getting a lock within a minute or less, which is what I'm used to. So, the only thing left is the invalid arg. error, when it is first starting up.

Any pointers on generally where I should look?

Thanks!

~Luke
Apr 18, 2009, 10:42 PM
Registered User
mecevans's Avatar
Quote:
Originally Posted by SteveRoss
Hi,

Does anyone know whether PPM Encoder will work with Futaba FASST radios (7C, 9C, 10C, etc.)?

Thanks.

It works with ANY RECEIVER WITH SERVO PINS.
Last edited by mecevans; Apr 20, 2009 at 12:42 AM.
Apr 19, 2009, 12:24 AM
Registered User
Luke,
The invalid argument Ive seen as an issue with how the Tiny/GCS deals with the non UTM coordinates. Should be fine once it goes away.

AJ
Apr 19, 2009, 05:32 PM
Registered User
Quote:
Does anyone know whether PPM Encoder will work with Futaba 7C FASST 2.4 Ghz radio? In Futaba 7C, only channel 3 (throttle) can be set into fail safe mode. The 3-position switch G for "Mode" is on channel 7 with no way to set the fail safe mode (I guess that the receiver will hold its last valid signal value for channel 7 in case the RF signal is lost).
Hi.
This is a problem as you must be able to set a failsafe value of 2000 microseconds to the "MODE" channel otherwise the system will not go to
"AUTO2" when the signal will be lost.
Other than that the ppm encoder will work alright.
Since you probably can't assign channels like The royal evo or the mc4000 you also can't assign channel 3 to be the "MODE" channel and move the throttle stick to another channel.
I could make a special firmware for you where you can set the failsafe for the throttle channel to max and then make sure that the throttle channel will not reach that value during normal operation by using the ATV limiter.
This way when the ppm encoder sees that the value for the throttle is the max it will switch to "AUTO2".
Chris
Apr 19, 2009, 09:50 PM
Registered User
Quote:
Originally Posted by hendrix
I could make a special firmware for you where you can set the failsafe for the throttle channel to max and then make sure that the throttle channel will not reach that value during normal operation by using the ATV limiter.

Chris
Chris,

I thought the firmware you just described has been in the version 3.8 code. Could you please tell me how to program the new special firmware to this PPM Encoder board. I knew that the PPM Encoder board has 2 x 3 AVR programmer pins. What other device is needed to program this PPM Encoder board? I checked the Futaba 7C manual and knew that the ATV is an older name for End Point Adjustment (EPA). I tried to set the EPA in fail-safe mode when the throttle in max position and change the EPA to 140% and record the 140% position as the fail-safe position. I then tried to change the EPA back to the 100% position (It is still under the choice of fail-safe mode, not normal mode for channel 3). If I turn off the Transmitter while throttle is at the 100% (normal max) position, I can see the extra 40% movement in the servo angle in channel 3 (throttle) after the Transmitter is off.


Thanks.

Steve.
Last edited by SteveRoss; Apr 20, 2009 at 04:03 AM.
Apr 20, 2009, 12:39 AM
David1
bmw330i's Avatar
Quote:
Originally Posted by mecevans
It works with ANY RECEIVER WITH STANDARD SERVO CONNECTORS.
Should work with any receiver regardless of the servo connectors. You could simply solder wires directly to the board and save space/weight. I imagine most UAV builders will want to solder their own connectors to save the space and weight by eliminating the RC servo connectors and pins.
Apr 20, 2009, 12:47 AM
Registered User
Quote:
Originally Posted by bmw330i
Should work with any receiver regardless of the servo connectors. You could simply solder wires directly to the board and save space/weight. I imagine most UAV builders will want to solder their own connectors to save the space and weight by eliminating the RC servo connectors and pins.
Chris is right, I have just tested my Futaba 7C FASST and it cannot get into the Auto2 mode because the 7C only allow channel 3 to be set into fail-safe mode, not the channel 7 (3-position switch G). I am waiting for Chris to reply my previous posting about the special firmware and the ATV in channel 3 (throttle), etc.
Apr 20, 2009, 12:54 AM
David1
bmw330i's Avatar
Quote:
Originally Posted by SteveRoss
Chris is right, I have just tested my Futaba 7C FASST and it cannot get into the Auto2 mode because the 7C only allow channel 3 to be set into fail-safe mode, not the channel 7 (3-position switch G). I am waiting for Chris to reply my previous posting about the special firmware and the ATV in channel 3 (throttle), etc.
Give him some time. It's the weekend and he's gone above an beyond to design it and give it freely along with the code to the community. That means tech support is up to us not him. Anyone is free to modify the code and then using an AVR programmer flash in the new program.
It's also a case where you want that feature and others want it to default into manual (like me). One of the versions out there before 3.8 I think did what you ask. It's posted online if you brows back (and Chris hasn't deleted/edited the post).
To program them is fairly easy. I bought an AVR programmer from SparkFun then installed AVRStudio software (Windows only). Using the two it's pretty easy to program following the steps Chris wrote. It also might help to google AVR ATMega168 programming with AVR Studio. It's no different for loading this code than any other code. Have patience it will get sorted out.


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