Hoverfly Tilt axis help with HFP

[i love nachos]

I have been trying to get this 2 axis gimbal set up for a few days. :black_eyed: I have the roll servo dialed in, but the tilt axis is a mess. I don't know if I am missing something on my setup through the HoverFlyPro (Green Board) or if the POT is bad. Its acting like a switch. Just on and off and the servo is always spinning the same way. I would appreciate any input you guys have.:nevreness:

http://www.youtube.com/watch?v=xqzNbZTaS_4

Thanks!
Nick

 

[Bartman]

nick,

who wired the pot? does the pot have stops at each end or is it a continuous rotation pot?

 

[i love nachos]

I wired it.

The pot does have stops on the ends. When its all the way to one side is when it turns off. All other positions the servo is running

 

[i love nachos]

http://copterframes.blogspot.com/2012/11/basic-servo-hacking-with-7-photo-shots.html

This is the guide I followed for the wiring if that helps

 

[Bartman]

there are three contacts in the pot, one at each end of the resistor element and one that sweeps across the resistor to give you varying degrees of resistance making position sensing possible. You've got three wires, you can't hurt anything by trying various combinations so desolder them and switch them around until you get the desired response. ONe combination will make the servo react opposite to what you need so be careful you don't get tricked into accepting that one.

good luck.

btw, i love nachos too!

bart

 

[i love nachos]

Awesome. I appreciate the advice. I will try that tonight!

...and we all love nachos.....

 

[i love nachos]

OK Bartman, I resoldered the wires in every configuration I could and the best result I got was it spinning the other direction.....

 

[Bartman]

OK Bartman, I resoldered the wires in every configuration I could and the best result I got was it spinning the other direction.....

something isn't right if the servo isn't responding at all as the pot is turned. are you sure the pot is the right spec, it's usually a 5k ohm potentiometer.

i'd recommend you pull the servo apart again and check your wiring, there may be two wires touching where you pulled the pot and tapped into the wires.

bart

 

[i love nachos]

ok i will check it out. the pot comes from the manufacturer and i am using the recommended servos. I will see whats going on inside the thing tonight hopefully. thanks again.

Nick

 

[i love nachos]

OK I had two wires switched inside the servo and I am getting movement in both directions finally. I messed with calibration for about 30 minutes and it kind of works. I am still not sure if my pot is acting correctly or not though. If I barley touch it the tilt servo just spins again. Should the base (the part that I soldered the wires onto) be locked in place? I will hopefully have more time to play with the calibration again tomorrow. The roll servo was so easy I am just not sure if I am missing something major with this tilt servo. Let me know if you have any ideas or if I can give you any more info. Thanks again

Nick

 

[Bartman]

nick,

if the servo spins in both directions as you move the pot then it's a matter of the wires being in the wrong order. there are only a handful of combinations so go through them again. as the pot gets close to the position the servo controller is looking for the servo will slow and then stop. if you keep turning the pot the servo will reverse direction and try to bring the pot back into position.

the controller in the servo is trying to move towards the commanded position by referencing the resistance in the pot. if the pot isn't responding the way the servo controller expects then it all goes to hell, as you've seen....

 

[i love nachos]

Well actually that's what I have it doing. I can turn the POT and the get the servo to slow down and pretty much stop. When I then lift the HEX up and start testing it with the HFP the servo responds correctly, but will then suddenly kick in to the death spin again. I guess I am just not sure if I have the POT mounted correctly at this point. The way its setup right now the whole thing rotates with the the pitch/tilt axis. Should the brain section with the wires on it remain stationary while the other end rotates with the pitch/tilt movements? Thank you again Bart

 

[Bartman]

Well actually that's what I have it doing. I can turn the POT and the get the servo to slow down and pretty much stop. When I then lift the HEX up and start testing it with the HFP the servo responds correctly, but will then suddenly kick in to the death spin again. I guess I am just not sure if I have the POT mounted correctly at this point. The way its setup right now the whole thing rotates with the the pitch/tilt axis. Should the brain section with the wires on it remain stationary while the other end rotates with the pitch/tilt movements? Thank you again Bart

Yes, absolutely, the body of the pot should be fixed and the shaft should rotate with the camera. many camera mounts, mine included, use the pot as a pivot point for one end of the camera tray.

You're getting close.

Bart

 

[i love nachos]

OK great. I appreciate the reassurance, I just needed the confidence that I was doing things correctly. I will continue on and report back!

Thanks
Nick

 

[i love nachos]

Got it mounted correctly and I am almost there. I am still having one issue though. The tilt doesn't come completely back to center when the aircraft is level. Not sure if that is a servo, pot or programming issue. I am going redo the wires tonight and see if that helps. Let me know of you have any other ideas. Thanks

 

[Bartman]

Got it mounted correctly and I am almost there. I am still having one issue though. The tilt doesn't come completely back to center when the aircraft is level. Not sure if that is a servo, pot or programming issue. I am going redo the wires tonight and see if that helps. Let me know of you have any other ideas. Thanks

if the pot/servo are wired correctly now you'll probably have to go back to the setup client and tweak the settings.

bart

 

[i love nachos]

I am thinking I have a bogus POT. When I move any of the wiring withing 2 inches of the connection the servo goes nuts and spins at full speed. So I think there is some kind of connection being made inside the POT when there is any pressure applied to the the prongs.

 

[Bartman]

I am thinking I have a bogus POT. When I move any of the wiring withing 2 inches of the connection the servo goes nuts and spins at full speed. So I think there is some kind of connection being made inside the POT when there is any pressure applied to the the prongs.

given the way it's been acting, it wouldn't be surprising if there's a short in there somewhere.

 

[Efliernz]

I have diy'd my camera mounts and have a variety of Pot feedback arrangements (direct and reduction)... but if you have to buy another pot, get a good one. Some cheap ones become intermittant with any flexing/movement near them.

Pete

 

[i love nachos]

Good tip Pete. I have heard that the way this gimbal mounts the pots that it is hard to use anything besides what is supplied. Any tips on where I can look for some new ones?