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Aug 13, 2012, 05:55 PM
OlliW
Thread OP
@dspctech:
please see PM

@kenw92:
the DIY adapter can be a pain to get it working, often it does but sometimes it doesn't. I didn't got how you confirmed that with 8.2k it is working... I mean, since the flash doesn't work it seems that the connection is not yet stable... I can't really give any advice, sicne, as I said, teh DIY adapter is tricky and every single item needs it's individual solution. The only advice I can give is to use the FTDI adapter. Form HK it's cheap now.

@andrejsstrumfs:
The programing box firmware is for the atmega88 or atmega88pa, but not the atmega8. The m8 and m88 are not fully compatible. Please use the m88/m88pa.

@MGeo:
check webpage again

@ALL:
although not really relevant to most readers here, but Mick Steidl has made the heroic effort to translate to German and extend the manuals by Holger and myself. See the project webpage http://www.olliw.eu/2011/ga250-gyro-firmware/#manuals. THANKS, Holger and Mick, for your hard work to support this project!
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Aug 14, 2012, 01:19 AM
Registered User
Quote:
Originally Posted by OlliW

@andrejsstrumfs:
The programing box firmware is for the atmega88 or atmega88pa, but not the atmega8. The m8 and m88 are not fully compatible. Please use the m88/m88pa.

Hi!

I use the firmware you made specially for atmega8, which was posted earlier in this thread. Or is it not going to work with v016 gyro firmware?
Aug 14, 2012, 04:02 AM
Registered User
MGeo's Avatar
Got it. I'll get on to programming.

Thank you OlliW, and thank you for your offer Steve.

George
Aug 14, 2012, 04:03 AM
OlliW
Thread OP
hahaha... I totally forgot about that

I have remodelled my DIY boc for another purpose, so I can't double check what I did, but, yes, you're right, the firmware should be working. However, my response to your question about the fuses was then INCORRECT, since also the fuses are different for m8 and m88(pa)... sorry for that. For the DIY box with ATmega8 I have this comment in my source file:

DIY: atmgea8
- SUT1:0= 11, CKSEL3:0= 1111, BODEN=0, BODLVL=1, Bootloader @ PD1/TXD with key, Fuses BOOTSZ1:0= 10, BOOTRST= 0
- low fuse: 0xBF, high fuse: 0xDC

I don't know whether you are using a bootloader. I guess not (since I seem not to have posted it for the DIY box), in that case the bootfuses should not be set. So, low fuse: 0xBF, high fuse: 0xD9. I don't know though whether the different fuses would affect the connectability between progbox and GA250. Maybe Hyvok can jump in and tell what he used.

If the fuses are not the issue and hardware wise everything else is double checked then you have to tell/show us a bit more about your box... I mean , the evil could sit everywhere. You're sure your ATmega8 is running at 8MHz from a crystal/ceramic? Could you describe how you tried to connect to the GA250? A (good) photo of your setup (showing the details)? I notice that in contrast to Hyvok scheme I did not use the 100Ohm resistor in the Rx/Tx line (R2 in Hyvok's scheme), not sure what this does.

I am connvinced that it is just a "little" thing which prevents correct operation, it might be just hard to find it... so, don't give up...

Olli
Aug 14, 2012, 04:34 AM
Registered User
MGeo's Avatar
OlliW,

Thank you for your awesome work.

I am trying to replicate your analyses from (https://www.rcgroups.com/forums/show....php?t=1538273) to gain a greater understanding of how the gyro works.

Would you be willing to share the Xcos model files from reply #5 (https://www.rcgroups.com/forums/show...59&postcount=5) in the post above? I would like to exercise them in Scilab/Xcos. I've downloaded and installed Scilab/Xcos (can't believe it is free!). I'm still climbing the learning curve to build and run models, source files would get me to there much with less chance for errors.

Best Regards,
George
Aug 14, 2012, 04:50 AM
Registered User
Quote:
Originally Posted by OlliW
hahaha... I totally forgot about that

I have remodelled my DIY boc for another purpose, so I can't double check what I did, but, yes, you're right, the firmware should be working. However, my response to your question about the fuses was then INCORRECT, since also the fuses are different for m8 and m88(pa)... sorry for that. For the DIY box with ATmega8 I have this comment in my source file:

DIY: atmgea8
- SUT1:0= 11, CKSEL3:0= 1111, BODEN=0, BODLVL=1, Bootloader @ PD1/TXD with key, Fuses BOOTSZ1:0= 10, BOOTRST= 0
- low fuse: 0xBF, high fuse: 0xDC

I don't know whether you are using a bootloader. I guess not (since I seem not to have posted it for the DIY box), in that case the bootfuses should not be set. So, low fuse: 0xBF, high fuse: 0xD9. I don't know though whether the different fuses would affect the connectability between progbox and GA250. Maybe Hyvok can jump in and tell what he used.

If the fuses are not the issue and hardware wise everything else is double checked then you have to tell/show us a bit more about your box... I mean , the evil could sit everywhere. You're sure your ATmega8 is running at 8MHz from a crystal/ceramic? Could you describe how you tried to connect to the GA250? A (good) photo of your setup (showing the details)? I notice that in contrast to Hyvok scheme I did not use the 100Ohm resistor in the Rx/Tx line (R2 in Hyvok's scheme), not sure what this does.

I am connvinced that it is just a "little" thing which prevents correct operation, it might be just hard to find it... so, don't give up...

Olli
Yes, i got correct fuses from Hyvok, actually i flashed the uC succesfully and the box itself is working, i get the text output on lcd. The crystal IS 8MHz and the fuses look ok too.. connection to gyro is very simple, don't think i could mess something up. But i will try without 100Ohm resistor. I tried to hook up my oscilloscope to gyro and box, and i see that the gyro is giving short pulse on signal wire when power up, but the box is only listening? Is that correct?
Aug 14, 2012, 06:25 AM
OlliW
Thread OP
the electrical connection is very simple, that's true... what I meant was is that the communication is not always possible at all times, i.e., it is only possible after power up (and a further trick). So, you disconnect the servo from the GA250's servo plug, you connect the progbox to the servo plug, and then power up the heli by connecting the lipo to the BESC... could you report what the leds on the GA250 are doing after power up? And what the box display is showing? (I am trying to figure out if you have some timing issues, the progbox should have "started up" before the GA250's blue led blinking finishes)

You can confirm that your fuses are SUT1:0= 11, CKSEL3:0= 1111? I had issues before with different (shorter) startup times.

The box should also respond very briefly. The communication protocoll is such that the GA250 sends one byte, then the box responds with one byte, and then the GA250 should send a couple (few ten) bytes, and this "frame" should repeat every about 15ms or so.

If all electrical connections and the hardware are correct, my guess would have been that somehow the progbox listen/talks at a different baudrate or runs at a too slow frequency.... these two reasons, a minor mistake in the progbox hardware or an incorrect clock frequency of the atmega are the two main issues I can see. The fact that the lcd and keys are working is not really telling that also the UART and/or MCU is working at the correct speed since the lcd/keys are not time critical, so from the lcds/keys one can't conclude that the box itself is really working correctly.

I am actually a bit puzzled that you have issues, and even more so since you seem to be experienced. The progbox is supposed to be a simple to build unit (usually the usb adapter is giving the head aches). Not sure what's going on here, I feel a bit of little help...
Aug 14, 2012, 07:01 AM
Registered User
Quote:
Originally Posted by OlliW
the electrical connection is very simple, that's true... what I meant was is that the communication is not always possible at all times, i.e., it is only possible after power up (and a further trick). So, you disconnect the servo from the GA250's servo plug, you connect the progbox to the servo plug, and then power up the heli by connecting the lipo to the BESC... could you report what the leds on the GA250 are doing after power up? And what the box display is showing? (I am trying to figure out if you have some timing issues, the progbox should have "started up" before the GA250's blue led blinking finishes)

You can confirm that your fuses are SUT1:0= 11, CKSEL3:0= 1111? I had issues before with different (shorter) startup times.

The box should also respond very briefly. The communication protocoll is such that the GA250 sends one byte, then the box responds with one byte, and then the GA250 should send a couple (few ten) bytes, and this "frame" should repeat every about 15ms or so.

If all electrical connections and the hardware are correct, my guess would have been that somehow the progbox listen/talks at a different baudrate or runs at a too slow frequency.... these two reasons, a minor mistake in the progbox hardware or an incorrect clock frequency of the atmega are the two main issues I can see. The fact that the lcd and keys are working is not really telling that also the UART and/or MCU is working at the correct speed since the lcd/keys are not time critical, so from the lcds/keys one can't conclude that the box itself is really working correctly.

I am actually a bit puzzled that you have issues, and even more so since you seem to be experienced. The progbox is supposed to be a simple to build unit (usually the usb adapter is giving the head aches). Not sure what's going on here, I feel a bit of little help...
Will double check the fuses, when i'm home, maybe i really messed up with them... And what trick you mention? I connect the gyro to box, power everything up, the gyro briefly flashes blue led and then starts flashing red, the box first display welcome message and then tells 'Device not connected' and stays this way.
Aug 14, 2012, 07:32 AM
OlliW
Thread OP
Quote:
the gyro briefly flashes blue led and then starts flashing red, the box first display welcome message
the welcome message on the box should last shorter than the gyro is flashing the blue led. I.e., the box should have finished with start up. welcoming etc, BEFORE the blue flashing ends and the gyro goes ahead with red flashing.
Quote:
And what trick you mention?
I found it inconvennient to always having to disconnect/connect the lipo, so it's possible to connect to the progbox by pluging it into the servo plug and hold the rudder stick for 10 secs to the left (the heli has to stand still)... this will make the gyro firmware to kind of restart and hence pass again the "try-to-connect-to-the-progbox-and-blink-blue-led" phase...
Aug 14, 2012, 10:07 AM
Registered User
Quote:
Originally Posted by OlliW
the welcome message on the box should last shorter than the gyro is flashing the blue led. I.e., the box should have finished with start up. welcoming etc, BEFORE the blue flashing ends and the gyro goes ahead with red flashing.
I found it inconvennient to always having to disconnect/connect the lipo, so it's possible to connect to the progbox by pluging it into the servo plug and hold the rudder stick for 10 secs to the left (the heli has to stand still)... this will make the gyro firmware to kind of restart and hence pass again the "try-to-connect-to-the-progbox-and-blink-blue-led" phase...
Now, i feel like stupid idiot
I used the red connector bootloader and i was sure i have to use red connector to connect prog box too. Tried the servo connector and all is working now, thanks
Aug 14, 2012, 10:48 AM
OlliW
Thread OP
No problem, I am glad your issue could be resolved that easily!
Have fun with flying. It would be nice if eventually you could report back your experiences
Cheers, Olli
Aug 22, 2012, 01:44 PM
Registered User
Hi Olli,
could you please describe how RUDD RATE exactly works?
I use iit on fixed plane and have 3pcs GA250 with RR 1.0 1.5 and 2.0 on rudder elevator and aillerons.
I wonder if RR multiplies inputs and trims to some limits or multiplies and use it in PID equation directly (with no limits trims)?
For example in TX I use 100% EPA x RR 2.0 = 200% Will I got 200% of gyro rate?
Thanks
Sep 04, 2012, 08:22 AM
Registered User
Steve Joblin's Avatar
Please ignore this post.
Last edited by Steve Joblin; Sep 04, 2012 at 01:59 PM.
Sep 04, 2012, 03:10 PM
Registered User
Quote:
Originally Posted by OlliW
No problem, I am glad your issue could be resolved that easily!
Have fun with flying. It would be nice if eventually you could report back your experiences
Cheers, Olli
Well, at last i got my heli together and weather was not terrible, so i had a chance to try gyro. I did not change any settings from default, so i got heavy back bouncing when turning counterclockwise but sharp nice stops clockwise. But wind was so strong, that i decided not to tweak the settings and wait for better weather. But at least it works and holds tail in strong crosswind
Sep 09, 2012, 09:54 AM
Registered User
Hi OlliWe

Great Work

Is it possible to convert code for DIY program box for BLheliBox (Atmega328)

Thanks Nick
Sep 10, 2012, 08:17 AM
OlliW
Thread OP
@ablack:
it just multiplies to the incoming rudd signal...

if the incoming rudd signal is e.g. 1639 us, it is centered by subtracting the signal for rudd midd (let's assume it to be 1507 us) and then multiplied by Rudd Rate (let's assume 1.1), so the rudd signal used by the gyro is then

1.1 * ( 1639 us - 1507 us ) = 145 us

@andrejsstumpf:
COOL
keep us posted how it goes further

@nikosd:
not sure I understand your question

if you are asking if it's possible to use the hardware, which you are using as progamming box for the modded GA250 (e.g. the Robe box or one of the various DIY boxes presented in the above) to operate as BLHeliBox, then the answer is: maybe. If it uses an ATmega8 or ATmgea88 then its no, if the mcu is ATmega168 or ATMega328p, then yes but with some (minor) hardware modifications

if you are asking if it's possible to use the hardware, which you are using as BLHeliBox, to operate as programming box for the modded GA250, then the answer is: most likely. If its a Arduino Uno + LCD shield, it can be directly used as GA250 programming box (I have the code somewhere, but think I have never posted it anywhere)


Cheers, Olli
Sep 11, 2012, 12:31 AM
Registered User
Good Morning OlliW

The second option

{ If its a Arduino Uno + LCD shield, it can be directly used as GA250 programming box }

Please if you have a code send us a link to download.

Have a good day Nikosd
Sep 13, 2012, 01:02 AM
Registered User
Quote:
Originally Posted by OlliW
@andrejsstumpf:
COOL
keep us posted how it goes further
Well, yesterday i had a chance to fly heli and tune the gyro. What can i say? It works really great At least from my unprofessional point of view. And sure i can recommend this mod to all heli flyers.
Oct 17, 2012, 09:32 AM
Registered User
Hi olliw,
I just programmed my hk450 gyro. However, each time that connect the battery, for a few instants, the servo reaches its end position, going to force the command on the tail beyond the limits. I'm afraid that in the long run can lead to the failure of the servo.
The servo is a MKS480, firmware is 0.16
I made a video to show my problem.

Assan GA250 gyro with olliw firmware 0.16 startup issue (0 min 15 sec)


Thank you for this fantastic project
Oct 17, 2012, 10:15 AM
OlliW
Thread OP
Hey Sparkie,

there is nothing obvious which comes to my mind here... unfortunately... so, we need a bit patience and have to do a bit of research (but I am sure we get this sorted out, so far it always got sorted out :-))

Maybe at first some little checks.

- The MKS480 can handle only 5.0V at most (it is IMHO also a bit "small" for a 450, but that's another cup of tea). I assume that you have checked that your BESC is not delivering more than 5.0V, and that the servo is working properly when e.g. attached directly to the reciever?

- According to the sepcs I found on the web the servo can handle 1520us at 333Hz. This should be perfect. Nevertheless, just as a quick double check, what would happen if you would set the gyro output to 70 Hz?

- You are sure you have connected the gyro correctly to the reciever? And that the reciever is set up properly (in particular failsafe settings can be a pain)

- You are sure that burning the bootloader and flashing the firmware was really successful? (maybe you could post a screenshot of the output tab of AVRootloader)

I know, most likely all this is perfectly OK, but things happen, you know, and I am just trying to sort out things... Ok, let's assume now a problem with the gyro. Unfortunately, as said, at the moment I can't be of much help, I'd like to ask for some more info:

- The GA250 has two Leds, a blue and a red one. What are the leds doing after you power up the gyro/heli? Try to look carefully and to report carefully what they are doing, the leds behavior can be a tremendously useful diagnosis tool. Repeat also with the gain switch at the transmitter set to heading hold and to rate mode. (in one of the first posts you find a description of what the leds are supposed to do, as well as in the pdf manual).

- Could you also post a screen shot of AvrConfig with the settings of your GA250? This too can be a most helpful info

- What transmitter and reciever are you using?

Cheers,
Olli
Oct 17, 2012, 10:41 AM
Registered User
Sparky79: It sounds like you have too much throw in your servo. Adjust your rudder links to compensate for that. You want full throw but not overriding. Then make adjustments in the gyro to make sure it do's not cause the servo to over ride. I have'nt used the gy250 for a long time so cannot remember how thats done Ed
Last edited by prop bender; Oct 17, 2012 at 10:43 AM. Reason: spelling
Oct 18, 2012, 04:26 PM
Registered User
Hello olliw,
thank you very much for your interest to my issue.
I agree with your methodical approach to problem solving and I will answer point by point.

Quote:
Originally Posted by OlliW
- The MKS480 can handle only 5.0V at most (it is IMHO also a bit "small" for a 450, but that's another cup of tea). I assume that you have checked that your BESC is not delivering more than 5.0V, and that the servo is working properly when e.g. attached directly to the reciever?
Of course, power supplies are ok, 5v leaves the bec and 5v enters into the servo
Quote:
Originally Posted by OlliW
- According to the sepcs I found on the web the servo can handle 1520us at 333Hz. This should be perfect. Nevertheless, just as a quick double check, what would happen if you would set the gyro output to 70 Hz?
I confirm the characteristics of servo, if i set output to 55Hz (70 is not present), nothing change, the issue remains.
Quote:
Originally Posted by OlliW
- You are sure you have connected the gyro correctly to the reciever? And that the reciever is set up properly (in particular failsafe settings can be a pain)
Of course, I checked all connections many times
Quote:
Originally Posted by OlliW
- You are sure that burning the bootloader and flashing the firmware was really successful? (maybe you could post a screenshot of the output tab of AVRootloader)
I think so, I have not see any alarming message during flash
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Description:
Quote:
Originally Posted by OlliW
- The GA250 has two Leds, a blue and a red one. What are the leds doing after you power up the gyro/heli? Try to look carefully and to report carefully what they are doing, the leds behavior can be a tremendously useful diagnosis tool. Repeat also with the gain switch at the transmitter set to heading hold and to rate mode. (in one of the first posts you find a description of what the leds are supposed to do, as well as in the pdf manual).
The problem seems to occur while the blue LED flashes, practically while bootloader is trying to establish a connection.

olliw ga250 firmware HH mode (0 min 21 sec)

Olliw GA250 rate mode (0 min 13 sec)

Quote:
Originally Posted by OlliW

- Could you also post a screen shot of AvrConfig with the settings of your GA250? This too can be a most helpful info
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Description:
Quote:
Originally Posted by OlliW
- What transmitter and reciever are you using?
Transmitter is a turnigy 9x reflashed with er9x firmware
Receiver is a turnigy 8 channels 2.4Ghz

If I find something I'll let you know immediately
Oct 18, 2012, 05:44 PM
OlliW
Thread OP
Hey Sparkie,

I first have to say that I'am impressed by the detailed info you gave, in particular the videos, good idea. I can confirm that you indeed have done everything expertedly, and that everything (except of course the servo) looks perfect. I also only now understand what your issue is. From your first post I was thinking that the problem is that the servo horn runs to an end position after power up and stays there. But looking at all videos the problem seems to be clearly in the initializing state.

There is actually one thing which I find confusing in the 3 videos, namely that the behavior of the servo after power up is not the same in all three videos:

video 1: servo in mid (?), power up, quick large deflection to the right, then big deflection to the left
video 2: servo mid (?), power up, quick large deflection to right just BEFORE the blue led goes on, ca. 1 sec in this position while blue led is on, return to mid after blue led goes off
video 3: servo mid (probably not exactly mid here?), power up, blue led goes on without any servo reaction, quick large deflection to right and back to mid position at the time the blue led goes off...

Not very consistent...

So, again some questions please:

- in the last two videos, if you would have let the power on, would the gyro and/or servo then have behaved as expected upon movements of the rudder stick and movements of the tail boom? (in short, once the initial deflection event is passed, does the gyro then seem to work?)

- have you tried another servo? (you can use a cyclic servo, or any other servo, but have the frequency set to 55Hz)(yes 55Hz not 70Hz, my mistake, I forgot that exact number LOL)

- would the tail servo work properly if you would put it into a reciever slot intended for one of the cyclic servos?

- if you would put the tail servo in a cyclic servo slot at the reciever, would power up everything, would wait a dozen secs for everything to settle, what would then happen if you would disconnect ONLY the servo signal line (not the gnd and power line) of the servo? What would happen if you would have plugged in the servo but WITHOUT the servo signal line connected, would power up everything and would then connect the servo signal line after a dozen secs?
(I'd like to learn about the servos' behavior if it doesn't see a signal).

- have you tested/used the gyro BEFORE you did the conversion? If so, what did the servo do then?


I can currently see only three explanations
- the servo is a dude
- the servo output signal cable of the gyro is damaged (e.g. bad solder joint, insulation layer cut through, slack joint... the gyro is IMHO pretty well build, nevertheless I had all this before)
- there is indeed a sort of a compatibility issue in that your servo behaves with a running-to-the-right-end when it's powered but doesn't get a valid signal at its signal line

Looking forward to learn the answers,
Olli

EDIT: there is another thing which came to my mind (sorry that it didn't earlier)... during the blue led period the gyro attempts to find a programming box at the servo plug, and for that purpose it emits some particular signals and looks if it gets a reasonable response to them. The point is that the emitted signals are not conform to a PPM signal a servo expects. All my servos didn't had any problems with ignoring these invalid signals, but it could well be that the MKS tail servo behaves differently here. If at the end this indeed turns out to be the case, there are only these solutions

i) accept the deflection (wich is probably no option because of mechanical binding?)
ii) another servo (maybe no option either)
iii) I have to modify the firmware and provide an option to switch off the programming box (a programming box could then not be used, sad sad)
iv) I have to generate another firmware which uses another plug for the programming box (at the disadvantage of some inconvennience in using it)
v) I have to rewrite the firmwares and change the communication protocol between gyro and programming box

hmhmhm... solution (iii) would be the easiest... let's see what your answers are, in particular if the gyro is working correctly otherwise.
Last edited by OlliW; Oct 19, 2012 at 02:00 AM.
Oct 19, 2012, 03:27 AM
Registered User

Fixed plane


Hi Olli,
I used use your fixed plane FW in plane some time so I have experience to talk about.
In rate mode is awsome. Sometimes it whip with ailerons, rudder or elevator during flight. Its not wag and its hardly to see because it has no influence on stability of plane.
In HH mode (I used only twice) it has issues. It seem that gyro has too much "angle memory". When i hit full throw and plane has low speed that is not able to has such high rotation speed around particular axis, then release the stick gyro continues to rotate around axis. Yes, its the role of HH, but it continues to hunt the angle too far. Comercial gyro has about 45° in possition memory, so there is only 45° turn "overshots" in these cases.
I think that on heli could be the same in cases when tail has low rotation speed ability.
What is your oppinion?
Thanks
Oct 19, 2012, 02:00 PM
OlliW
Thread OP
Hey ablack,

thanks for your biref feedback, much appreciated.

What setting are you using for the Controller Structure? Fixed Wing?

It's correct, my implementation works slightly different in some aspects than the commercial (heli) gyros (I don't have any knowledge for fw gyros). And one difference is that in default, as you observed, the HH "memory" is much longer than in commercial gyros. But you can adjust this via the I Limit and Gyro Limit parameters in the experts menu. I have not played around with them myself, but I would expect that e.g. reducing I Limit should reduce the angle memory (I don't know but you might have to lower it to something like 150 for a 45° memory).

For helis I can't see any problem with that (at least I never experienced any), since the maximum rate the tail can be turned is not very dependent on the flight condition. However, I understand what you're saying, that for a plane the max rotation rate depends strongly also on the speed of the plane.

Try plaing with the above limits (don't go higher than the default, but you can lower them).

Cheers, Olli
Oct 19, 2012, 04:14 PM
Registered User
Quote:
Originally Posted by OlliW
Hey Sparkie,

I first have to say that I'am impressed by the detailed info you gave, in particular the videos, good idea. I can confirm that you indeed have done everything expertedly, and that everything (except of course the servo) looks perfect. I also only now understand what your issue is. From your first post I was thinking that the problem is that the servo horn runs to an end position after power up and stays there. But looking at all videos the problem seems to be clearly in the initializing state.

There is actually one thing which I find confusing in the 3 videos, namely that the behavior of the servo after power up is not the same in all three videos:

video 1: servo in mid (?), power up, quick large deflection to the right, then big deflection to the left
video 2: servo mid (?), power up, quick large deflection to right just BEFORE the blue led goes on, ca. 1 sec in this position while blue led is on, return to mid after blue led goes off
video 3: servo mid (probably not exactly mid here?), power up, blue led goes on without any servo reaction, quick large deflection to right and back to mid position at the time the blue led goes off...

Not very consistent...

So, again some questions please:

- in the last two videos, if you would have let the power on, would the gyro and/or servo then have behaved as expected upon movements of the rudder stick and movements of the tail boom? (in short, once the initial deflection event is passed, does the gyro then seem to work?)

- have you tried another servo? (you can use a cyclic servo, or any other servo, but have the frequency set to 55Hz)(yes 55Hz not 70Hz, my mistake, I forgot that exact number LOL)

- would the tail servo work properly if you would put it into a reciever slot intended for one of the cyclic servos?

- if you would put the tail servo in a cyclic servo slot at the reciever, would power up everything, would wait a dozen secs for everything to settle, what would then happen if you would disconnect ONLY the servo signal line (not the gnd and power line) of the servo? What would happen if you would have plugged in the servo but WITHOUT the servo signal line connected, would power up everything and would then connect the servo signal line after a dozen secs?
(I'd like to learn about the servos' behavior if it doesn't see a signal).

- have you tested/used the gyro BEFORE you did the conversion? If so, what did the servo do then?


I can currently see only three explanations
- the servo is a dude
- the servo output signal cable of the gyro is damaged (e.g. bad solder joint, insulation layer cut through, slack joint... the gyro is IMHO pretty well build, nevertheless I had all this before)
- there is indeed a sort of a compatibility issue in that your servo behaves with a running-to-the-right-end when it's powered but doesn't get a valid signal at its signal line

Looking forward to learn the answers,
Olli

EDIT: there is another thing which came to my mind (sorry that it didn't earlier)... during the blue led period the gyro attempts to find a programming box at the servo plug, and for that purpose it emits some particular signals and looks if it gets a reasonable response to them. The point is that the emitted signals are not conform to a PPM signal a servo expects. All my servos didn't had any problems with ignoring these invalid signals, but it could well be that the MKS tail servo behaves differently here. If at the end this indeed turns out to be the case, there are only these solutions

i) accept the deflection (wich is probably no option because of mechanical binding?)
ii) another servo (maybe no option either)
iii) I have to modify the firmware and provide an option to switch off the programming box (a programming box could then not be used, sad sad)
iv) I have to generate another firmware which uses another plug for the programming box (at the disadvantage of some inconvennience in using it)
v) I have to rewrite the firmwares and change the communication protocol between gyro and programming box

hmhmhm... solution (iii) would be the easiest... let's see what your answers are, in particular if the gyro is working correctly otherwise.
here I am
I can confirm that the servo is working properly in other configurations.
I tried another servo and it does not suffer this the issue, I noticed, however, that during the blue led phase, this servo emits four distinct short ticks. Probably, as you say, these are attempts to contact the programming box. Also the mks servo is programmable The mks servo and probably these pulses immediately after power up will deceive him.
The programming box serach is done by the firmware or boot loader?
I'll give you this question because i thought that motivation immediately and so I tried to program the red gain plug bootloader alternative but nothing is changed.
Can you try to insert a 1 or 2 sec loop in the firmware before blue led procedure?
Another option might be an attempt to 'sense' servo on start up (I think that the servant has an internal pullup) and if it is detected, skip blue led phase.

What do you think about that?

Thank you
Cosimo
Oct 19, 2012, 09:54 PM
OlliW
Thread OP
Hey Cosimo,
thanks for the info

Once the blue led goes off, does the gyro then behave as expected, i.e. once the initial deflection event is passed, does the gyro then seem to work?

Quote:
The programming box serach is done by the firmware or boot loader? ... so I tried to program the red gain plug bootloader alternative but nothing is changed.
smart idea, but its in the firmware, the bootloader has finished by then (it runs only for ca 0.3 secs)

Quote:
Can you try to insert a 1 or 2 sec loop in the firmware before blue led procedure?
not sure what your real intention is here. From your tests do you have evidence that the servo would accept false signals once it has gotten correct signals for a short period? That is, this
Quote:
- if you would put the tail servo in a cyclic servo slot at the reciever, would power up everything, would wait a dozen secs for everything to settle, what would then happen if you would disconnect ONLY the servo signal line (not the gnd and power line) of the servo? What would happen if you would have plugged in the servo but WITHOUT the servo signal line connected, would power up everything and would then connect the servo signal line after a dozen secs?
(I'd like to learn about the servos' behavior if it doesn't see a signal).
would not lead to a deflection of the servo but would work?


Quote:
Another option might be an attempt to 'sense' servo on start up
well, the box would also be a load, would be difficult to distinguish whether its a "servo load" or a "box load"...

Generally the implementation of the programming box feature gave me headaches... because many things have to work hand in hand... (and I had some specific goals such as for instance that you don't have to reprogram the programming box when you install a new firmware on the gyro, that you don't have to modify the hardware of the Robbe box, etc. pp, otherwise it would have been much easier)(also, the GA250, or better the Spartan Quark, is ill designed for that purpose... even Spartan apparently had issues with the design, otherwise they would not have had to "invent" the fancy need of a special inconvennient linker)

At one point I decided that the gyro has to be the active player. But this came from another project (the GA250 coax gyromixer project) and I wonder if, for the GA250 alternative firmware, I could not have made the box the active player... (which would avoid the issue)... can't see a problem at the moment, but might miss it... and it would need some substantial work

Another, easy to implement option would be to look for the rudder signal at startup, and jump into the blue led mode if it is e.g. fully right or left. This would be easy and not too inconnvenient for a user, but bears the problem that you can construct situations where the servo again would see a false signal (and deflect and bind), e.g. then you start with rudder fully left but have the servo still connected... should happen rarely and if must not be totally destructive... so, this approach is relatively safe but not totally safe

The best solution in some ways would be to modify the hardware of the GA250 by soldering a servo cable to the GND, VCC, and maybe SCK pin of the ISP pads, i.e., to kind of build a special programming port.

The ultimative solution would be to switch off the blue led phase at the cost that a mobile programming box can't be used anymore.
Oct 20, 2012, 01:36 AM
Registered User
Hi Olliw
Quote:
Originally Posted by OlliW
Once the blue led goes off, does the gyro then behave as expected, i.e. once the initial deflection event is passed, does the gyro then seem to work?
Sure, the gyro works wery well after blue led goes off. Occasionally it happens that the servo does not respond at all (probably it has entered the programming mode) but after disconnecting and reconnecting the servo, it resumes operation immediatly (the gyro is ok)

Quote:
Originally Posted by OlliW
smart idea, but its in the firmware, the bootloader has finished by then (it runs only for ca 0.3 secs)

not sure what your real intention is here. From your tests do you have evidence that the servo would accept false signals once it has gotten correct signals for a short period? That is, this
would not lead to a deflection of the servo but would work?
Not a good idea, i thought that the servant in the first seconds might be more sensitive to impulses. I do another test:
- servo power connected directly to receiver
- gyro power (red plug) disconnected from receiver
- plugged in battery
a this point servo doesn't see any signal and won't initialize but if i shortly touch the +5v pin with the signal line, servo start to move towards right end
- plugged in gyro power
same old problem

Quote:
Originally Posted by OlliW
well, the box would also be a load, would be difficult to distinguish whether its a "servo load" or a "box load"...
But programming box comm line is not normally down? If servo has a internal pull up, on startup you can do a quick:
Line low -> check for programming box
Line high -> nothing

Quote:
Originally Posted by OlliW
The best solution in some ways would be to modify the hardware of the GA250 by soldering a servo cable to the GND, VCC, and maybe SCK pin of the ISP pads, i.e., to kind of build a special programming port.
This can be a good alternative.
Oct 20, 2012, 02:32 AM
OlliW
Thread OP
Quote:
Sure, the gyro works wery well after blue led goes off.
ha, LOL, this wasn't very clear to me from the beginning

OK, I guess we have nailed down the problem, that's a good thing (and your diagnosis efforts where very helpful)

Now we only have to hammer out a solution...

If (and only if) you would like to go with the extra programming plug option (it needs some soldering and some modifying the gyro case, both would be obviously a piece of cake for you, but I am not sure you like to go this route), I should be able to quickly send you an modified firmware (I should have to change only one line in my code and recompile).

Otherwise I guess I would go with the rudder stick left/right procedure. It's the easiest to do and nearly safe.

Äh, I should have asked actually beforehand, do you actually have or plan to use a programming box?

good work, Cosimo


PS: the line of the box is normally high impedance (=nothing) since its an input, but it has a pull up resistance, both similar to what a servo would have (but it was another good thought!)
Oct 21, 2012, 10:00 AM
Registered User
Quote:
Originally Posted by OlliW
Hey ablack,

thanks for your biref feedback, much appreciated.

What setting are you using for the Controller Structure? Fixed Wing?

It's correct, my implementation works slightly different in some aspects than the commercial (heli) gyros (I don't have any knowledge for fw gyros). And one difference is that in default, as you observed, the HH "memory" is much longer than in commercial gyros. But you can adjust this via the I Limit and Gyro Limit parameters in the experts menu. I have not played around with them myself, but I would expect that e.g. reducing I Limit should reduce the angle memory (I don't know but you might have to lower it to something like 150 for a 45° memory).

For helis I can't see any problem with that (at least I never experienced any), since the maximum rate the tail can be turned is not very dependent on the flight condition. However, I understand what you're saying, that for a plane the max rotation rate depends strongly also on the speed of the plane.

Try plaing with the above limits (don't go higher than the default, but you can lower them).

Cheers, Olli
Thanks Olli for advise.
Im using fixed wing controler structure.
I will try to experiment with I limit asap.
I also have a remark to switching modes of gyro by gain signal and RUDD RATE multiplier. From my experience it would be nice if each gyro mode (rate, HH, OFF) could have its own RUDD RATE multiplier. Now I have some not easy solution by using complex mixing in TX, but its not transparent at all. Im using all 6 mixers only to tune RATE and OFF mode. I miss mixers for tunning HH mode.
Fo explanation, in RATE mode roll is slow, in HH fast, in OFF insane fast. Dual rate helps only a little because I cant program my TX to switch modes and D/R by one switch.
What do you think about this?
One more question, when I use RUDD RATE 2.0 do I loose any resolution?
Thanks
Oct 21, 2012, 12:17 PM
OlliW
Thread OP
hey ablack
Quote:
it would be nice if each gyro mode (rate, HH, OFF) could have its own RUDD RATE multiplier
I understand what you're saying. But to be honest I am not going to implement it. The firmware has increased in complexity quite a bit because of the fixed wing support, and introducing further parameters wouldn't be convenient at all for all others. I mean, if there would be 20 fixed wing pilots jumping out of the woods and wanting to use the modded GA250, then it could be worth a thought to branch off a fixed wing version, but that's not what it is (remember, that's my hobby and not my bussiness, and I don't have any fixed wings...). So, this is mainly a heli gyro.

I would think that any programmable transmitter should provide at least two flight modes. Not sure why yours doesn't.

Quote:
Fo explanation, in RATE mode roll is slow, in HH fast, in OFF insane fast.
Is this actually a commonly known issue with fixed wing gyros?

Quote:
One more question, when I use RUDD RATE 2.0 do I loose any resolution?
I think that this should not be any problem.

cheers, Olli
Oct 21, 2012, 12:33 PM
Registered User
Quote:
Originally Posted by OlliW
Now we only have to hammer out a solution...

If (and only if) you would like to go with the extra programming plug option (it needs some soldering and some modifying the gyro case, both would be obviously a piece of cake for you, but I am not sure you like to go this route), I should be able to quickly send you an modified firmware (I should have to change only one line in my code and recompile).
this might be enough to solve my problem. I would not have difficulty to modify my gyro to get new programming port

Quote:
Originally Posted by OlliW
Otherwise I guess I would go with the rudder stick left/right procedure. It's the easiest to do and nearly safe.
This may be the best solution in a general vision of your project. I think it may be more difficult for you but this solution might solve my problem to other people in future.

I leave you the decision.

Quote:
Originally Posted by OlliW
Äh, I should have asked actually beforehand, do you actually have or plan to use a programming box?
No,my computer it's enough for me


Thanks Olliw!
Oct 21, 2012, 12:53 PM
OlliW
Thread OP
Quote:
No,my computer it's enough for me
if you don't need the progbox support I also could just switch it off (i.e. no blue led seqence)... have send you a PM
Oct 21, 2012, 01:19 PM
Registered User
Quote:
Originally Posted by OlliW
hey ablack
I understand what you're saying. But to be honest I am not going to implement it. The firmware has increased in complexity quite a bit because of the fixed wing support, and introducing further parameters wouldn't be convenient at all for all others. I mean, if there would be 20 fixed wing pilots jumping out of the woods and wanting to use the modded GA250, then it could be worth a thought to branch off a fixed wing version, but that's not what it is (remember, that's my hobby and not my bussiness, and I don't have any fixed wings...). So, this is mainly a heli gyro.

I would think that any programmable transmitter should provide at least two flight modes. Not sure why yours doesn't.

Is this actually a commonly known issue with fixed wing gyros?

I think that this should not be any problem.

cheers, Olli
Olli,
yes I see. I hope there will be more fixed wing FW version users because it could be well parametrized and still is smaller than KK 2.0.
Yes I can program 3 modes (gain), but only 2 modes (3 gain channells) I can mix in my DX7.
I dont know because I use only 3 GA-250 in plane.
As far as I know cheap 3-axis plane gyros uses only rate mode and are not even switchable from TX.
Thats not a problem. I only have to find compromise between modes.
With I limit I would solve the main HH flight issue.
Thanks
Oct 21, 2012, 01:29 PM
OlliW
Thread OP
the 3 flight modes of the DX7 do not allow to also set the D/R independently?

I understand that you can't set different D/R easily depending on the gyro gain switch, but why not using the 3 flight modes for No gyro, Rate gyro, and HH gyro and set each for your specific wishes... (and kind of inactivate the gyro gain switch)

looking forward to hear if the I Limit has allowed to get your HH behavior right
Oct 21, 2012, 03:53 PM
Registered User
Quote:
Originally Posted by OlliW
if you don't need the progbox support I also could just switch it off (i.e. no blue led seqence)... have send you a PM
Bingo! Problem solved!
Thanks Olliw!
Oct 22, 2012, 09:54 AM
OlliW
Thread OP
GREAT!

once you're airborne, would you tell? I'd like to add you then as a user to my web page, if you allow

have fun, Olli
Oct 26, 2012, 02:29 AM
Registered User
Hi OlliW,

Please tell me how can I login to your site to get this firmware. I've registered and got email with password in return, but unfortunately I'm getting following error:
"Du hast nicht die erforderlichen Rechte, um auf diese Seite zuzugreifen." My knowledge of German is "nicht zu gut" but in my understanding it means "You don't have required privileges for login to this site". What am I doing wrong?
Oct 26, 2012, 02:36 AM
Registered User
Quote:
Originally Posted by OlliW
GREAT!

once you're airborne, would you tell? I'd like to add you then as a user to my web page, if you allow

have fun, Olli
OK
Helicopter took off successfully with tail perfectly stabilized.
Yes, add me to your web page.

Cheers
Cosimo
Oct 26, 2012, 03:32 AM
OlliW
Thread OP
hey Dazur,

ha, you have not done anything wrong... you just need to give me the chance and time to approve your registration request...
Should work now. So, welcome to the club.

hey Cosimo,

fantastic. Thx for reporting back. I've added you. Maybe you could consider posting your setup and parameters (heli type, transmitter/reciever, head speed, tail servo, Rate Gain, PID Gain, PID I, frame length, debounce, etc. pp.). There are still too few of these reports to see trends for useful parameters...

heli:
Tx: turnigy 9x reflashed with er9x firmware
Rx: turnigy 8 channels 2.4Ghz
head speed:
tail servo: MKS480
GA250 parameters:
Last edited by OlliW; Oct 26, 2012 at 04:38 AM.
Oct 26, 2012, 02:34 PM
Registered User
Thanks OlliW. I just flashed it and it looks like everything is working perfectly. I plan to use it in a fixed wing so have to become familiar with all those options, but it'll be a joy I'm sure. If those two I own meet my expectations I'll buy a next batch for future use. THANK YOU VERY MUCH FOR YOUR EFFORT FOR THE COMMUNITY.
Oct 29, 2012, 08:58 AM
Registered User
Quote:
Originally Posted by darzur
Thanks OlliW. I just flashed it and it looks like everything is working perfectly. I plan to use it in a fixed wing so have to become familiar with all those options, but it'll be a joy I'm sure. If those two I own meet my expectations I'll buy a next batch for future use. THANK YOU VERY MUCH FOR YOUR EFFORT FOR THE COMMUNITY.
Great another GA-250 OlliFW fixed-wing user
I can comfirm it works well i my plane. I have used it on 900mm and now on 1200mm aerobatics plane.
Oct 29, 2012, 11:51 AM
Registered User
Quote:
Originally Posted by ablack
Great another GA-250 OlliFW fixed-wing user
I can comfirm it works well i my plane. I have used it on 900mm and now on 1200mm aerobatics plane.
Hi ablack,

For testing purposes I will put two of them to my small EPP flying wing. If they pass this test then will be used in 1.8m nitro Decathlon on tail and ailerons. Can you share your fixed wing settings?

P.S. I noticed on the bench that with this gyro is not possible to use trims. After every gyro reboot it centers the servo no matter how much trim I apply even in rate mode. Is it normal? I have two other piezo gyros (E-Sky EK2-704B) and they allows me to use my trims.
Oct 29, 2012, 06:56 PM
Registered User
Quote:
Originally Posted by ablack
Great another GA-250 OlliFW fixed-wing user
I can comfirm it works well i my plane. I have used it on 900mm and now on 1200mm aerobatics plane.
Quote:
Originally Posted by darzur
Hi ablack,

For testing purposes I will put two of them to my small EPP flying wing. If they pass this test then will be used in 1.8m nitro Decathlon on tail and ailerons. Can you share your fixed wing settings?

P.S. I noticed on the bench that with this gyro is not possible to use trims. After every gyro reboot it centers the servo no matter how much trim I apply even in rate mode. Is it normal? I have two other piezo gyros (E-Sky EK2-704B) and they allows me to use my trims.
Just subscribed to this thread ...

Interesting to see a guy from olomouc, a city that I did cross my car countless time, and the first polish guy not far from my polish place 'wroclaw'

Still studying the work of OlliW ... thinking if I will ever hack my ga250

Tchuss

E_lm_70

Ps: in the other world I read exactly what did puzzle me ... this gyro has 3 free pin, 2 in, 1 out ... perfect for map a normal usart ... instead of hacking with diode and use 1 line only ... if just firmware would be open ... it will be nice to play with it
Nov 03, 2012, 10:55 AM
Registered User

New Adopter


I'm a newb. Just putting it out there.

I got my parts in from HobbyKing. Once all the soldering was completed everything else was straight forward.

I did have to burn the bootloader twice before I could flash the firmware using the avrloader.

I uploaded the firmware and left all settings at default for the time being. Flew for about 3 lipos. Tail was holding excellently. Unfortunately I am still learning how to fly a little better.


Keep RC 450 Pro
DX6i
Spectrum RX
Gain at 73.5%
Emax 9258
Calculated head speed 2900 rpm
Nov 07, 2012, 01:58 AM
Registered User
Quote:
Originally Posted by darzur
Hi ablack,

For testing purposes I will put two of them to my small EPP flying wing. If they pass this test then will be used in 1.8m nitro Decathlon on tail and ailerons. Can you share your fixed wing settings?

P.S. I noticed on the bench that with this gyro is not possible to use trims. After every gyro reboot it centers the servo no matter how much trim I apply even in rate mode. Is it normal? I have two other piezo gyros (E-Sky EK2-704B) and they allows me to use my trims.
Hi,
yes you have to trim all mechanically and not by trims in TX. I did it on the ground so all is in one line when still and 0 trims.
Then fly with gyro OFF to check, make slight changes and then in most cases its OK after one or two flights.
Or you can trim in flight in RATE mode, on the ground note posittion of trims or mechanical position and then program trim in gyro (or make mechanical adjustments).
But, when you use gyros on fixed wing all the time you dont need to make precise mechanical adjustment, gyro makes the plane stable, so no diving or rolling occurs even the plane is untrimmed.
Nov 07, 2012, 03:45 AM
Lt. Col. Crash 'n Burn
Hi Olli,

Great work you have done here! I'm really impressed, and I would love to try your FW on my GA-250. I tried to register on your site yesterday, but I haven't received any emails yet?

My GA-250 (with the original FW) doesn't seem to work very good in my HK-250GT.
It would be nice to try your FW on it, instead of just buying a new (and more expensive) gyro.

Thanks.


\ Martin
Nov 07, 2012, 05:02 AM
OlliW
Thread OP
@dazur:
a trimming via TX shouldn't work for a gyro in hh mode, also not for the commercials ones (and for all gyros I know, and all gyros I read about, this is indeed not possible).

if you don't like the auto-center feature at start-up, you can switch it off by setting the parameter Rudd Mid Mode to fixed (go to the Advanced tab in AvrConfig). You can the select the mid value which should be used by the gyro with the parameter Rudd Mid, a value of 0 us means a rudder signal of 1520 us, a value of 10 us means 1530 us, and so on.

@dazur, ablack:
doing the trimming mechanically is the best, but to a significant extend you can achieve the same with the Servo Mid parameter! that's why it is where, you may wish to try it.

@netmav:
patience, my friends... I am not always focused to 100% of my time on this project, you know, family, work, other projects, etc. pp
should work now though
Nov 07, 2012, 08:15 AM
Lt. Col. Crash 'n Burn
Quote:
Originally Posted by OlliW
@netmav:
patience, my friends... I am not always focused to 100% of my time on this project, you know, family, work, other projects, etc. pp
should work now though
Hi Olli,

I understand completely.
I still haven't received any emails, though? And if I try to register again, I get a message saying that the username and email address is allready registered?
But I don't have a password, and if I click on "Forgot password", both my username and email address is not recognized?
I'm sorry for all the trouble..

Now to something completely different: While I'm waiting for the FTDI adaptor to arrive, I was thinking about building the DIY adapter. But I don't have any Shottky diodes, so I was wondering if anybody know if it will work with "standard" 1N4148 diodes instead?

Thanks.


\ Martin
Nov 07, 2012, 08:45 AM
OlliW
Thread OP
hey Martin

you've got a PM

just try the 1N4148... you can't damage anything... no idea if its will work or not (and the DIY adapter reportedly worked very dependent on the particular computer, so its hard to make any predictions anyhow)


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