Cheap 5D gimbal

[apejovic]

Are those Savox 360º? If so will you use an external pots? I´m happy with the gimbal results but I think it will work much better with good servos. Also my biggest problem is that the 90º pitch I get with the hitecs is not enough for the works I use to do. Please keep me informed once you receive the gimbal.

 

[hexacop]

I will modify the Savox myself for 360° operation with external multiturn potentiometer. It's not a big deal and can be done easily.

 

[mbsteed]

I am a bit naive when it comes to servos pots - could someone explain what those are used for and how one goes about adjusting those and why you would want to do that.

 

[Bowley]

Anaka...Followed your advice out of necessity, I dropped my X650 from roughly 100ft and broke among other things the roll gearing on my XA CM130 TPS. In the absence of any available parts, as yet, for these mounts I modified it to a direct linkage push/pull in roll axis. I would actually say this has improved its performance. This makes me think the MC6500 could work well with the right servo's and FC. I wonder it would work with 2 good quality Head Hold Gyros.

View attachment 4501View attachment 4502

 

[hexacop]

Yes ik has ballbarings. 2 for roll and 4 for pitch.
They are placed inside the 6mm POM
But one on the roll isn't fitting well. Going to fix that.
The rest fits very well. No play at all. (is play the correct word for this?)

In the meantime I got my gimbal too and can add some comments.
Yes it has got ball bearings but actually those are useless. As the shaft is a simple 3mm thread it can't fit perfectly in the ball bearing and of course this is ends up in play. Also the tilt belt gearwheel has a 3.2mm bore and it is mounted on the the 3mm thread, so it is impossible to mount it 100% centered.
The reason why the wheels are made from white material is that the white material is the little more expensive one called POM (Delrin), the black material is not POM it is a cheaper plastic which is not as stiff as POM is.
The gimbal feels solid enough for a light weight camera like a GH2 or a Nex, but I would not use it for a heavy camera > 1kg
Some of the crews are 5mm too long and it would be better to use self-locking nuts instead of the simple nuts which should be secured http://dict.leo.org/ende?lp=ende&p=DOKJAA&search=nut&trestr=0x801 with locking varnish.
My conclusion is; yes the gimbal is usable but you must be able to improve yourself.
This is what I plan to improve:
1. replace the screws with shafts
2. add external poti to the tilt axis in conjunction with a modified gear ratio and a Savöx servo.
3. replace the simple camera plate by a camera plate mounted on gel type bushes to avoid vibrations

 

[anaka]

Hi Bowley, happy to help you i'd like to see some videos

I can suggest one more improvement, just in the case you will need to improve even more the performances, you should use aluminium linkages or bigger plastic linkages, more you make the connections rigid and more you reduce eventual jittering

one more improvement you can make is to have the linkage elements work more perpendicular, in your pictures i can see that they dont work aligned to the servo, this could produce problems in stability

wich electronics do yuo have? MK or Dij?

 

[apejovic]

1. replace the screws with shafts
2. add external poti to the tilt axis in conjunction with a modified gear ratio and a Savöx servo.
3. replace the simple camera plate by a camera plate mounted on gel type bushes to avoid vibrations

It´s great news to hear that you have received the gimbal. I´ve been working with it and as you said once "fixed" it works fine. I have upgraded it to 360 pan but for me now it´s mandatory to change the servos with some decent digital ones. The provided servo due to it´s pulse setup it´s only allowing me 45º of manual control (I do get 90º with the stabilization controller) Can you tell me exactly which/where pot and servo should I buy for both axis? Shipping is slow here in the Canary Islands so I could order the parts and then set them up with your help (thanks in advice).

I have added two levels of antivibration, one with rubber m3 male female parts between the gimbal and my lower frame and another one between the 360 platform and the upper part of the frame. For now I´m quite happy with the lack of vibrations. I think another interesting way to reduce them would be putting moongel between the gimbal´s upper tube and the two plates that actually link it to the frame.

Here you can see some of the tests I´ve done with the 360 setup:

 

[hexacop]

I'll be using the Savox SC-1257TG servos and modify the tilt servo with a external potentiometer.
You can get 5k potentiometers manufactured by Eti Systems, Bourns or Vishay.
I've replaced the roll servo gear with the larger gear which was mounted on the tilt servo. This modification is needed to reduce the gear ratio of the roll gear and to be able to maintain the roll angle using servos which do not turn 180° like the Hitec servos used by the builder of the gibmal.
Next I've completely replaced the tilt drive with my own belt drive with a ratio of 4:1 to get more resolution on the tilt.
As soon it will be finished I'll post some pictures.

 

[hexacop]

Here we go, the modifications as mentioned in the previous thread.
Modified gear ratio on roll
View attachment 4846
New gear on tilt with external potentiometer on the other side of the camera plate.
View attachment 4847
The camera plate is mounted on alpha gel pads to absorbe vibrations.

 

[apejovic]

Nice work hexacop. I will try to do the same to mi gimbal. I need a buying list, so lets start:

1-Servo: I found this at a good price http://www.ebay.es/itm/Savox-SC-125...Control_Parts_Accessories&hash=item58946c2951 but I also noticed that freefly used savox until they have now made their own servos that already come modified for 360º. I don´t know if these are better than the savox or they have simply rebranded them. These are the ones http://www.kopterworx.com/vmchk/Spares-Cinemastar/CS-360-servo . Let me know if you have any information about those, if not I´ll order the 1257TG.

2- Gear: You mention you have put the provided tilt gear on the roll. With my gimbal I got both roll and tilt with the same gear. Can you tell me the specs and where should I order all the gears and belts neccesary for doing your same modification to both the roll and tilt?

3- Pots: Does any 5k potentiometers manufactured by Eti Systems, Bourns or Vishay do the work or should I get them for a certain number of turns?

I hope you will post your tests soon.

Sorry for the questions but I want to be sure before ordering everything.

Heres a quick work I´ve done a few days ago:

 

[TooSlow2Care]

i'd love to get my hand one of these... too bad the seller won't ship to the US. ( and has no stock at the moment)

 

[hexacop]

1-Servo: agree the Savox is proven to work fine for a reasonable price, I don't now how the servos from kopterworx.

2- Gear: I get my gears either from
Maedler http://www.maedler.de/Product/1643/1616/986/987.aspx
or GHW Modellbauversand
http://www.modellbauershop.de/antrieb/zahnriemenscheiben-teilung-t-25.php

3- Pots: In general you can take any good 5k potentiometer, you need only one for the tilt axis, multi turn is not necessary in this case.

 

[apejovic]

1-Servo: agree the Savox is proven to work fine for a reasonable price, I don't now how the servos fromkopterworx.

2- Gear: I get my gears either from
Maedler http://www.maedler.de/Product/1643/1616/986/987.aspx
or GHW Modellbauversand
http://www.modellbauershop.de/antrieb/zahnriemenscheiben-teilung-t-25.php

3- Pots: In general you can take any good 5k potentiometer, you need only one for the tilt axis, multi turn is not necessary in this case.

Hexacop thanx for the info:

1: Ordered 2x 1257 TG shipping is slow here in the Canary Islands so they should be here in 10-15 days.

2: Could you send me the reference number of the gears and belt you used for tilt axis from any of the two dealers (maedler or modellbauershop). As I told you before my gimbal came with both tilt/roll gears of the same size (black color not white). You said your tilt had a different ratio so you have moved it to the roll axis. Could you tell me also which belt and gear should I buy from the previous dealer to take advantage of the savox on the roll. Am I right thinking that with a 4:1 ratio with the original unmodified savox I should get 40-45º of rotation?

3: Found these pots here in Spain, 3852A BOURNS POTENTIOMETER 1 TURN AXIS 6mm 5K Ohm, here are the specs: http://descargas.cetronic.es/3852.pdf I suppose this one should work could you confirm me that before ordering?

By the way, how are your progresses with your modified gimbal? Are you happy with the results?

Vielen Danken

 

[Reginak]

Hey guys!

I'm not a DIY person, can't someone point me a ready gimbal to carry a 5D? I have a skyjib6 and now i'm building a second machine, a cinestar 8. But I don't want to spend US$1600,00 (I think) on a cinestar 360 gimbal right know. Is there a good gimbal and ready to use?

Thanks

 

[hexacop]

@apejovic, You need the following:
Tilt gear: gears with 84 and 16, belt 245
Roll gear: gears with 72 and 18, belt 230
http://www.modellbauershop.de/antrieb/zahnriemenscheibe-azetalharz-teilung-25-16-z.php
http://www.modellbauershop.de/antrieb/zahnriemenscheibe-azetalharz-teilung-25-84-z.php
http://www.modellbauershop.de/antrieb/zahnriemenscheibe-azetalharz-teilung-25-18-z.php
http://www.modellbauershop.de/antrieb/zahnriemenscheibe-azetalharz-teilung-25-72-z.php
http://www.modellbauershop.de/antrieb/zahnriemen-teilung-25-wl-245.php
http://www.modellbauershop.de/antrieb/zahnriemen-teilung-25-wl-230.php
The potentiometer looks good, you can use that.

I did not had much time to test it, but the first impression is good.

@Reginak
you may have a closer look to the AV200 from photohigher.

 

[apejovic]

@hexacop Thank you very much.

I´ll order the pots and gears inmediately. Once I get the parts I´ll just need to sort out how to modify the savox for continuous rotation, I suppose it´s done adding 2 x 1k resistors in the place of the internal pot and removing the gears physical limit. Like it´s done in this tutorial:

It would be nice if you could post some photos of how you adapted the pot on the tilt roll.

Thanks again for being so helpfull.

 

[hexacop]

The video you posted is related to some cheap servos, you don't want to do it like that ...
Look at this tutorial how they modify it, the Savox servo is very similar...

But, in our case we need to remove and unsolder the potentiometer, do not glue it like shown in the video!

The potentiometer is fixed with 2 screws, you can unscrew those with a little screwdriver by pushing the pcb a little bit (1-2mm) to the side. After you have removed the 2 hidden screws you can pull out the electronics (including the motor and the potentiometer) from the servo case.
After that you can unsolder the potentiometer and solder a 3 wire cable (servo cable).
Be aware of the potentiometer turn direction and where you connect the 2 poles of the potentiometer. If you reverse them your servo will turn into wrong direction and will damage the potentiometer...

 

[apejovic]

@hexacop: I have received the savox servos but unfortunately I still had no time for ordering the other parts. I know the setup will not be complete until I get the rest and tilt will be much shorter in travel (130/2=65º against the actual 180/2= 90º) without the 360 mod + pot, but in a few days I will exchange the hitecs for the savox just to see how much improvement the savox will provide against the hitecs (I hope it will improves a lot)

I´ve been quite busy lately including some tests done at 2300 meters, here´s a small reel made by some of these works:

I hope you find some time and show me your tests with the improved gimbal.

 

[apejovic]

@hexacop: Do you know which is the recommended hz setup for the savox? I have read they can handle 333hz and was plannning to use them at 300hz and 6v. I suppose mid pulse should be 1500 µs with min and max values of 1100-1900 µs. What is your setup?

Thanks

 

[Thomb]

did you guys noticed hes now selling the gimball with the pots?