Hackberry portal Forum HACKberry Q&A S03N servo substitute

This topic contains 6 replies, has 3 voices, and was last updated by  Hiroshi Yamaura 4 years, 3 months ago.

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    Hi all,

    I have problem with GWS S03N servo, Its already stop production.
    I checked with others servo and found that 3001 servo also come with ball bearings, but using nylon gear, so not suitable here.
    Search entire Hobbyking.com, and most metal geared standard servos are high torque, too high for Hackberry.

    May I know if the EMAX ES08MD can can be used to substitute the S03N by adding another 3D printed servo bracket to suit ?
    is it enough torque for the index finger ? if it is enough torque, then the BOM can be simplified, and also easier to buy one type of servo. The palm also have more empty space, and maybe can make the whole palm slightly thinner.

    If the ES08MD not enough torque for the index finger, then please discuss which one is suitable , I even open a MG995 servo ( 15KG) and try to add resistor in series with the motor to reduced its torque but not really successful.


    Hi Ew,

    I have been using 3001HB. It seems to work very well.
    ES08MD barely has enough torque for the three fingers.


    Hiroshi Yamaura

    Thank you for the information!
    I will add 3001B to BOM as a substitution of S03N.

    The torque of ES08MD is 1.6 kg・cm@4.8V or 2.0 kg・cm@6V.
    The torque of S03N is 3.4 kg・cm@4.8V.
    Maybe ES08MD can work but the torque is not so strong.
    I can’t say it is enough or not.

    ES08MD’s electrical circuit is also not so strong. If you repeatedly stall the motor, it may burn.
    (Therefore, I recommend you to insert polyswitch to each motor if you want to make the hand more durable).



    Hi Tima, Thanks for your info. I will buy some 3001HB servo. Its nylon geared , thats why I’m worry at first, but since you already tested , I think should be OK to use.

    I also don’t know if 1.6Kg.cm@4.8V is enough for the index fingers or not, I will try to make a servo mounting adapter and try it out. Good to know that the smaller ES08MD will burn out the circuit if stalled for a longer period. I will see what modification can be done in the ES08MD circuit, other than using polyswitch. User might drop the object they holding when the polyswitch is cut off.

    Thank you.



    You’re welcome.

    Hiroshi, would you try 3001HB with ABS gears?



    I also bought couple of EMAX ES08MA II , which is the same as ES08MD but its an analog servo, and the MD is digital servo. I will try to stall it and see if the mark II of MA series can last longer than the 08MD, without burning it circuit.

    I will share info here once I received it from HongKong.



    Hiroshi Yamaura

    Sorry, 3001HB is not common in Japan.
    I can buy it from Pololu but it takes time for shipping.

    I just added 3001HB to BOM as a substitution for S03N.

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