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Old Jan 09, 2008, 05:31 PM
Registered User
Joined Jan 2005
731 Posts
Discussion
1.2 gm servo improvements

The 1.2gm servo has been updated to use the original gears from
4.3/4.7 gm servos without purchasing a 2nd set of gears. The output
gears are made by modifying G5 and G6 from orig. servos.

I will have a number of the updated units completed for sale in 2
weeks.

See attached photos of completed servo and individual parts. The servo
weight includes 2" wire leads and connector pins. The servo operates on
3 to 5.5V and has >1 oz. thrust. The servo is made from the following
parts: 4 x 8 mm, 10 ohm pager motor; 3mm, 10k ohm feedback pot;
five 1/64" laser cut ply parts, 2 CF & 1 Alum gear shafts, 6 gears from 4.3 gm
servos, servo amplifier from United Hobbies 4.3 gm servo, # 36 AWG
stranded wire. If you are interested in some of these servos
let me know. I sell completed/tested servos and complete kits for
DIY. Note: The DIY kits should only be attemtted by those who have
mechanical and soldering skills, to work with very small parts!






I have tested these servos in 1/2 oz to 3 oz airplanes with great results.
The 1/2 oz airplane operates on a single 90mah Lipo cell.
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Last edited by scharlach; Mar 28, 2008 at 10:45 AM. Reason: Updated design
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Old Jan 09, 2008, 05:53 PM
Inciting Riots
village_idiot's Avatar
Joined Dec 2006
9,682 Posts
Is it correct to assume that the gears and circuit board are from the same servo?
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Old Jan 09, 2008, 06:23 PM
I used to be all thumbs...
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United States, KS, Pittsburg
Joined Mar 2005
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Very impressive!!!
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Old Jan 09, 2008, 06:59 PM
Thanks for the Fish!
aerogel's Avatar
Land of cajuns
Joined Dec 2001
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I love it...it's what I love about this board
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Old Jan 09, 2008, 07:10 PM
Good Better Best quest.
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Australia, VIC, Cranbourne East
Joined Apr 2004
10,354 Posts
I think hes done a fine job one suggestion i would like to make is ,if you take the allum cover off a floppy disc a u shaped chanel could be formed into wich the servo could be built ,this not only would be light but dimensionally stable to keep gear mesh tolerences lash free.
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Old Jan 09, 2008, 08:13 PM
Registered User
Joined Jan 2005
731 Posts
servo gears

Yes, you can use pinion gear, and gear 2,3,4,5 from 4.3gm servo but
you need to order a second gear 3 as this size gear is used twice in
this design. BP Products carry gear sets for Arrow 4.3gm servos.
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Old Jan 09, 2008, 08:21 PM
A&P Mechanic
may-day's Avatar
San Antonio
Joined Mar 2005
326 Posts
will you sell any pre built servos?
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Old Jan 09, 2008, 08:27 PM
Inciting Riots
village_idiot's Avatar
Joined Dec 2006
9,682 Posts
OK, thanks. I wonder if we could source that extra gear from someplace like http://www.smallparts.com so that the waste could be kept down. I guess the extra gears would be useful for repairs.
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Old Jan 09, 2008, 08:40 PM
:)
Dongo's Avatar
Here, There, Somewhere
Joined Jul 2004
267 Posts
Hey,

What servo board are you using the Blue Arrow 4.3g or the EM 4.3g? What about the pot, source or datasheet?

Thanks,

Daniel.
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Old Jan 09, 2008, 09:00 PM
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AleG's Avatar
Bangkok
Joined Oct 2007
1,587 Posts
Quote:
Originally Posted by scharlach
Yes, you can use pinion gear, and gear 2,3,4,5 from 4.3gm servo but
you need to order a second gear 3 as this size gear is used twice in
this design. BP Products carry gear sets for Arrow 4.3gm servos.
How about using less gears? less weight and complexity.

Here´s a picture of my attempt at modding an 7.5g servo; end weight is 2.5 but doesn´t work, way too jittery. I think it should be OK with a second gear reduction.

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Old Jan 10, 2008, 03:16 AM
Registered User
ITALY
Joined Sep 2004
913 Posts
diy servo

This is the servo that i make:
http://it.youtube.com/watch?v=vvHrTpgxhZo
little 2g servo (0 min 22 sec)
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Old Jan 10, 2008, 04:41 AM
diy heli maker
U.S.U.L's Avatar
Poland
Joined Sep 2004
615 Posts
Scharlach, thanks for posting.
I already bought two nokia 3210 vibra motors(4x8mm), will they be strong enough?

I also wonder about choosing the right SMD pot, they make much resist while being turned and this reduces speed and torque a lot. Did You try to mod them anyhow?
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Old Jan 10, 2008, 05:00 AM
Registered User
ITALY
Joined Sep 2004
913 Posts
info

For my experience in work with diy servo you have to use 4x8mm motor 24 ohm or 4mm motor 13ohm.Please verify the ohm between the + and - of your motor.Ivan
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Old Jan 10, 2008, 05:24 AM
It's a spiderweb of knit lines
Souderton Pa. USA
Joined Mar 2002
2,633 Posts
Hi scharlach,
Thanks for posting you servo, it looks very nice! I was working on doing a similar servo but with a worm drive. My problem was the shaft connection to the pot, can you show how you did yours?
Thanks,
Mike
Edit: On closer examination of your parts picture I see how you did it.
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Old Jan 10, 2008, 05:42 AM
A.K.A sir Crashalot
methuso's Avatar
Östersund, SWEDEN
Joined Sep 2005
888 Posts
For trimpot, would a Vishay TS3Y do ?
http://www.vishay.com/docs/51041/ts3y.pdf

(Im Electically challenged)

/Ulf
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