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I am trying to build a robotic arm and also using a lot of metal in it, now the real challenge for me have arrised at first I was using tower pro mg995 but that servo is worse than scrap. So I ditched them and got myself Johnson geared motors. Now as long as I apply the voltage the motor running holds the weight and move it to the desired position but when current is shut down it drops it. Please help me understand the concept of holding torque or even how much duty cycle will be required to hold the motor in place. I am using external potentiometers for position feedback and have achieved accuracy with it. Also I have cut open the tower pro servo to use its gear mechanism and found it worked nice so I wonder if I could use them too. I aim to control 8 motors but for the time being struggling with just one. Please help. And one more question should I consider using L298N IC for the motor control and not build my own H-Bridges.

Thank you, you guys are awesome.

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    While you can break the motor by essentially connecting both ends of the coil through the driver, that breaking might not be enough. It might need active driving of the motor to keep the position. So how are you currently moving to a set position? A common way of achieving such things would be implementing PID control in your software. Please show us your current code.
    – chrisl
    Jul 10 at 13:42
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    @st2000 I understand your point and that is the reason why I said I am using potentiometer to get the position feedback. Jul 10 at 14:39
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    @chrisl I had tried the breaking mechanism by short circuiting the wires of the motors but the force was of more intensity. Should I consider a gearbox for further reduction, I have an option to 3d print the mechanism. Jul 10 at 14:39
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    Dynamic breaking is likely not going to stop a motor as it only generates a stopping force when objects are in motion. This is the reason a lone locomotive is more dangerous (only or mostly relies on dynamic breaking) then an entire train (now the engineer has air breaks on all the cars attached to the train). So, if you are going to cut the power, you likely need a mechanical break. Posting in this forum usually indicates a low budget project. So I would consider a small amount of friction applied to the motor shaft so that you can take advantage of the gear box multiplication effect.
    – st2000
    Jul 10 at 14:58
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    Do you really need to cut power? Then you definitely need mechanical braking. Otherwise just keep driving the motor actively. Please show your code
    – chrisl
    Jul 10 at 16:34

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