Simple Questions for small Motors

Hello. I am doing a project which a part of it is about controlling small robots. I am at the point where i am looking for components, actually the motors.

Questions:

(1) for the movement of the whole robot, the most appropriate (i think) is a dc motor. No greate accuracy needed just power, forward and reverse. Does anyone know where to buy small dc motors in UK? I looked RS electronics but i cant find any. (small and cheap)

(2) What are the appropriate motors to use for simple movements on the robots. For example moving a small arm. I am a bit confused between servo and stepper motors.

Please keep in mind that the robots will be contructed using LEGO parts and will be approx. 15-25cm long.

Thank you for reading.

demestav said:

Hello. I am doing a project which a part of it is about controlling small robots. I am at the point where i am looking for components, actually the motors.

Questions:

(1) for the movement of the whole robot, the most appropriate (i think) is a dc motor. No greate accuracy needed just power, forward and reverse. Does anyone know where to buy small dc motors in UK? I looked RS electronics but i cant find any. (small and cheap)

Click to expand...

RS Components do some cheap model makers motors, they also do VERY expensive professional motors!.

(2) What are the appropriate motors to use for simple movements on the robots. For example moving a small arm. I am a bit confused between servo and stepper motors.

Click to expand...

A servo (usually) only turns a limited number of degrees, but it does this as an absolute position - i.e. you tell it a position to go to, and it goes there. Because it's a geared DC motor, it's small and powerful.

A stepper motor only provides relative positioning, you can tell it to move a number of steps from it's current position, either clockwise or anti-clockwise, but you have no way of knowing where it was in the first place. Steppers are generally expensive and fairly low powered - as they aren't normally geared.

Please keep in mind that the robots will be contructed using LEGO parts and will be approx. 15-25cm long.

Click to expand...

If you're using Lego parts, why not use the Lego motors?.

hello nigel and thnx for the reply.

If you're using Lego parts, why not use the Lego motors?.

Click to expand...

That is because LEGO motors are very very overpriced ( in my opinion ).

demestav said:

That is because LEGO motors are very very overpriced ( in my opinion ).

Click to expand...

All lego parts are 8)

As far as the motors go, the ease of use will help to compensate for the cost.