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Stronger Servo For Arms Strength.

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ok i bought 10 of these hd servos. tower pro mg995 digi hi-speed. I set up my arm or omni3000. One servo in the wrist, one servo in the forearm and 1 servo joining the upper arm to the body. when i was testing it out without the claw attached the arm moves perfectly. after i added the claw when it goes to lift up it moves quickly even though i have a speed controller set to 4 and disconnects from ez-b causing me to re-connect via bluetooth and do it all again. so i figure i need 2 xtra heavy duty servos for the arm to body attachment. any ideas?

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Are you running them with the power from the EZ-B?

I found I needed to make an external power board, throw in a 6V regulator and power them that way with Melvin's arms as they were browning out the board. I found the same happened with his head servos (all of which are MG90s or MG995s)

This is what I knocked up;

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And powered it from the battery directly, via a regulator. I used an Etronix 6v Lipo Regulator


Yeah, rich is correct. You can run the heavy duty servos off the EZ-B... only until you start drawing more power than the EZ-B can provide. Eventually you will need to power the servos off the battery itself.

I use a 6 volt or 7.2 volt battery with no issues using the Heavy Duty Servos in my Omnibot 2000

Keep in mind... you may eventually burn one out because they're lifting LOTS.... but I have only burnt one Heavy Duty Servo in 1.5 years Smile


would this regulator work?

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also for extra support on the arm-body joint. if i used a lazy susan bearing 3" attached to the arm socket and attached the other side to the arm center the servo and run. in theory this might work just like the 6" bearing works on the waist. I noticed that the weight of the arm rides on the little metal servo pole. you guys have been doing this longer than myself, so I will go by your suggestions.


I found this. It's not the cheaper way but it's a clean board for a lazy builder like me. Grin

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As far as the bearing, I will throw back together Pinhead soon and show what mine is doing with direct drive servos with a hub relief bearing mount. That will give you a reference. However, I will be changing it to a worm gear arrangement in the future like the one I recommended to you in the other thread.


That regulator should work if you have over 8V in. It is good for 5A so that will be 2 or 3 heavy duty servos. You can use more than one and have for instance 1 regulator for the left arm, 1 regulator for the right arm, 1 regulator for the head etc.

Troy's idea is also a cool one. I've been playing with a PCB for a while to make a board that is all on one, regulator and output pins at 0.1" spacing so you can just plug the board in to the EZ-B ports for the signals and the servos in to the boards. But I've not had chance to test the regulator circuit or anything yet.


@aameralis you can use A bearing to help support the shoulder but it won't give the servo more torque. You could grab a couple gearbox kits From servocity they have two heavy duty ball bearings and are rated for up to 200 pounds lateral weight support each. I have two they are nice.


Here's two options. The first is just something to keep in mind
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This is your best option , use your current servo and insert it into.
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This is the gearbox with mounting tabs I think you would utilize to mount against the omni torso.

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