Looking to control a Servo motor with an arduino

Help & Support Robot Parts
1

Hi

I am looking to control a servo motor with an Arduino or Rasberry Pi. I can control a normal RC servo, but require a slower speed and more torque. I have found the below item and am currious about which one is the traditional signal wire, as a normal servo only has 3 cables normally?

robotshop.com/uk/devantech-1 … Al-N8P8HAQ

Thanks

Mark

2

That’s not really a servo. Do you mean an RC hobby servo? You would need to look here:
robotshop.com/uk/servo-motors.html
Note that these tend to rotate only -90 degrees to +90 degrees.
Do you need a DC gear motor which accepts RC input?

RB-Dev-40 is a brushed gear motor with an encoder and does not have onboard electronics (aside from the encoder).

3

I basically need to control movement slowly, 180 degrees travel is fine, need slow and high torque.

Just want to know if an encoder can transmit a signal to an arduino or rasberry pi, the same as a standard servo does, allowing 3 of these motors to be controlled, dependent on each others positions?

4

You can program the servo to accept the signals from the encoder (Arduino is easiest because the pins are at 5V, whereas on a Pi they are 3.3V).
To control a DC motor like a servo (speed and direction only, not position), you need a DC motor which accepts RC PWM input:
robotshop.com/uk/rc-motor-controllers.html
You then program the Arduino to read the encoder output to know relative position.

5

So there is no way to know the position, as with a standard servo.

Can you recommend anything as the big cnc servo are a bit pricey and I thought this would act as a cheap alternative.

Also if I want to use a rasberry pi I could use an external power supply?

Thanks