DIY Servo Motor: Cheap and with Plenty Muscle!

DC Motors can be made to turn either clockwise or counter-clockwise by changing the polarity of the voltage applied to their terminals. The torque that is generated at the output shaft can be scaled up or scaled down by using a gear train.

What is torque? In simple words, torque is a quantity that decribes the ‘strength’ of a motor. A motor torque of 50 kgcm means that lifting a 50kg weight at 1 cm could be achieved with that motor. By the law of moments, lifting 50 kg at a distance of 1 cm is equivalent to ……

Lifting 500 kg     at 0.1 cm
OR    Lifting 5 kg        at 10 cm
OR    Lifting 0.5 kg        at 100 cm

In most motors, like the one shown below, the gear train scales up the torque of the motor by using a reduction gearing that outputs a much higher torque (albeit at the cost of a much reduced output RPM).

Geared DC Motor

Geared DC Motor: This one generates 120kg-cm torque at 3.5 RPM

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DC Motor Control Class for Arduino

One of the most rewarding aspects about building robots is understanding and designing individuals components, getting them to work and finally putting everything together into a more complex machine.

DC motor control under test

DC motor control under test

One of the key design aspects I am trying to learn is component re-usability. I don’t know what the technical term for this is, but in essence it means that I need to build components that are generic and can be reused in different robots with little or no modifications needed. This concept is very similar to Classes in Object Oriented Programming, something that I am trying to learn as well.

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