Motors for Arduino and embedded PC projects

Question

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.)

shabaz · Accepted Answer

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 mo st 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).

shabaz · Answer

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.

Motors for Arduino and embedded PC projects

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