Hi all,

I am having a problem with the controllor of my tinygo GEPRC drone. the issue is that i am experiancing ia input in the roll and pitch direction without touching the controller. The controller is centered. I have already tried oploading the following CLI: https://geprc.com/wp-content/uploads/202....2.5-1.txt. 

And adjusting the various roll components in the cli file to compensate for the values displayed. It seems that the gyroscope is functioning fine and the controller is giving the correct inputs for throttle and jaw. Does anybody know how to fix this issue or how to compensate for this?

Thanks in advanced

roll pitch and yaw need to be 1500, as examüle on roll; 1600 value is gently roll to the right and 1400 is gently to the left...

only throttle is from zero to 2000.

i guess all is right and you missunderstood the values?

Hi, thanks for the reply. I am aware that the roll, pitch and yaw should be 1500 for a stable system. however the rolla and pitch are standard 1648 and 1671 as in the picture. thus creating an instable system which is impossible to fly. these values are immediate as i turn on the drone and with no controller input. There is probably something wrong with the potentiometers or something in that ranged but i cant seem to fix it on the software level.

Any ideas are appreciated

Am I correct in assuming that if you connect the FC to Betaflight Configurator with your controller switched OFF that the Roll, Pitch and Yaw bars stay centred with a value of 1500, but as soon as you switch your controller on that the Roll and Pitch bars move to values of 1648 and 1671 respectively? If that is the case then it's a problem with the gimbals in your controller. I would try taking the case of the controller apart and look to see if there is anything obvious fouling the back of the gimbals of if there is any debris in them. If not, then try re-seating the connectors from the gimbals to the main board by unplugging and re-plugging them. Unfortunately there doesn't appear to be any photos of the of the internals of the GEPRC GR8 transmitter anywhere so you are going to be doing that blind without any help. If you do manage to get the back off the controller case then it would be helpful for reference purposes if you could take some nice clear photos of the internals and post them back here.

Which version of the GEPRC GR8 controller do you have? Is it the earlier version (which makes use of some kind of proprietary FHSS protocol), or is it one of the later GEPRC TinyRadio GR8 version (which makes use of the ExpressLRS protocol)? If you're not sure, post up a photo of the label on the back of your controller so we can see the information printed on it.

(06-Mar-2024, 10:30 AM)SnowLeopardFPV Wrote: Am I correct in assuming that if you connect the FC to Betaflight Configurator with your controller switched OFF that the Roll, Pitch and Yaw bars stay centred with a value of 1500, but as soon as you switch your controller on that the Roll and Pitch bars move to values of 1648 and 1671 respectively? If that is the case then it's a problem with the gimbals in your controller. I would try taking the case of the controller apart and look to see if there is anything obvious fouling the back of the gimbals of if there is any debris in them. If not, then try re-seating the connectors from the gimbals to the main board by unplugging and re-plugging them. Unfortunately there doesn't appear to be any photos of the of the internals of the GEPRC GR8 transmitter anywhere so you are going to be doing that blind without any help. If you do manage to get the back off the controller case then it would be helpful for reference purposes if you could take some nice clear photos of the internals and post them back here.

Which version of the GEPRC GR8 controller do you have? Is it the earlier version (which makes use of some kind of proprietary FHSS protocol), or is it one of the later GEPRC TinyRadio GR8 version (which makes use of the ExpressLRS protocol)? If you're not sure, post up a photo of the label on the back of your controller so we can see the information printed on it.

Hi that is correct as soon as i turn on the controller the values change from 1500 tot 1648 and 1671. I was able to disasemble the controller but i have no clue which versions it is. I check for anything in the gimbal and nothing. i also reseated the connector and i still have the 1648 and 1671 values. here are some images

Oscar and others talk about calibrating the gimbals. Try that.

(06-Mar-2024, 02:03 PM)segler999 Wrote: Oscar and others talk about calibrating the gimbals.  Try that.

Hi how do I do that in betaflight (not an expert at all)

Thanks for posting images of the internals. I think those are currently the only internal images of the GEPRC GR8 controller that have been posted anywhere on the internet.

segler999 makes a good suggestion. With no screen on the controller and no software for it I didn't think that it was possible to (re)calibrate anything on the GEPRC GR8 transmitter after it had already left the factory, but there is actually a section on stick calibration at the bottom of the 3rd column in the user manual (click HERE for the user manual). So try following that procedure and see if it solves your issue.

Quote:The Rocker keep in the center and calibrated

Hold the left and right rocker still, press and hold the SETUP button for more than 4 seconds until the buzzer beep three times continuously, and the center calibration is completed successfully.

(06-Mar-2024, 02:21 PM)SnowLeopardFPV Wrote: Thanks for posting images of the internals. I think those are currently the only internal images of the GEPRC GR8 controller that have been posted anywhere on the internet.

segler999 makes a good suggestion. With no screen on the controller and no software for it I didn't think that it was possible to (re)calibrate anything on the GEPRC GR8 transmitter after it had already left the factory, but there is actually a section on stick calibration at the bottom of the 3rd column in the user manual (click HERE for the user manual). So try following that procedure and see if it solves your issue.

Thanks for the suggestions that indeed did work, i am baffled that the fix was so easy. Thanks for the help all!

I guess opening up the controller turned out to be an unnecessary exercise, but on a positive note your posted photos might help someone else who needs to see what the internals of a GEPRC GR8 look like, so you've at least helped the FPV community by contributing those