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Motors for Arduino and embedded PC projects

amrrahmy

I have read a bit about the differences between DC / servo / stepper motors, but I would like to know more before delving any deeper.

 

the projects will use

  • Arduino Uno (possibly Arduino Zero in the future or other ARM micro-controllers),
  • 5.3V 2A USB smartphone charger as the input

 

wanted to make a "pan / tilt"(possibly 360 degree) platform for a solar panel (3W or 5W + the weight or the platform (probably made of wood))

  • are there any pros or cons if I use a servo vs stepper motor(more components, more expensive, more power required, more accuracy)

 

wanted to make a lift(elevator) and pulley system that would lift and move maybe 1-2KG(2-4 pounds) across 1 meter distance(might add hydraulics if needed)

  • would a DC motor have more torque if I added gears or would I be better off looking for a servo motor(any additional electronics needed for either? transformers, more power required to do the same job, ...etc.)
  • 0

    Hi Amr,

     

    There is a post here that highlights some differences between the various types of motors. There are example photos there too, so you can recognise the motors.

    A 3W/5W panel is fairly small, so you could possibly use a hobby servo, I don't think you need much accuracy. If you use a stepper or some other motor then you need a driver circuit; you won't need that with a hobby servo.

    For a suitable circuit for brushed motors, consider the infineon DC motor driver board. It is overkill if you just want to drive a very small motor though. (Also I think most cheap motors are not brushless by the way).

    Virtually any motor can lift 2-4 pounds, as long as it is geared down heavily enough (but then will take time performing the motion of course).

  • 0 in reply to shabaz

    Thank you for the quick reply,

     

    I have settled on the 2 servo for the pan / tilt panel. I can plug the servo into external power source and plug analog wire into the Arduino, right? it would not need to take power from the Arduino?

     

    I am still confused about

    • motor drivers and driver shields (this is for higher voltage devices?)
    • transformers and mosfets (I think its for controlling a higher voltage circuit using a lower voltage circuit)
    • ESC for brush-less motors (this is for higher current devices?)
  • 0 in reply to amrrahmy

    Hi Amr,

     

    You can connect the hobby servo to an external supply yes, and connect the control wire to a digital output on the Arduino (a pulse width modulation or PWM signal is used, see here).

    Motor drivers are for controlling a power source (e.g. battery) to drive a motor, based on control from the Arduino. They are needed because motors use far higher power that the digital outputs available from the Arduino. The analog signal is not used - it is easier to rapidly pulse the digital signal to control speed based on PWM.

    Transformers or MOSFETs are used to construct motor drivers, but it is harder than just buying a motor driver board. (The Infineon board blog post describes what the internals look like using MOSFETs in a

    'Half-Bridge' or 'H-bridge' representation , but it is just a high level diagram. Beware there are plenty of bad circuits circulating on the Internet that attempt to construct motor driver boards from discrete semiconductors).

    For brushless motors a different circuit is needed, sometimes known as an ESC. Like any other motor, brushless motors use higher power than the Arduino outputs are capable of.

    Again, transistors or MOSFETs (technically a MOSFET is a transistor by the way - just by 'transistor' alone people usually mean a 'Bipolar Junction Transistor' or BJT) are used to construct this circuit too.

  • 0

    My suggestion for lift is use high torque (less RPM) gear motor and by using arduino's PWM pin you can control motor position as well as speed too. By doing this you will get accuracy in lift.