12V DC Motor Attachments

Question

I have an Arduino that I am running two DC motors off of. I have the L298N motor shield that I am using to power the motors. Now that I have the system hooked up and running, I want to add the next step.

My end goal is that I want to create a robotic 'arm' of sorts and write some code that can move the different 'joints' independently. I just want to be able to code an action directly so I don't need functionality where I manually control the movements.

I've been trying to find DC motor 'attachments' or 'heads' that I can build on top of the motor so when it spins, it will move the piece but I can't seem to find anything that fits the little DC motors (some of the heads are for Servo motors). I'm really attempting to build this from scratch so I'm trying not to use any 'kits' and am trying to learn about the different components that would go into building this. Everything I find seems to point me towards a kit or something which sort of defeats the purpose of building it from scratch.

Are DC motors ok for this or should I be looking into something like a servo motor?

Also, I'm aware there is a robotics stack exchange forum but this seems to fall under this a little better because I'm basically just trying to get an idea of what kinds of attachments can go with a DC motor and what exactly I can be using them for.

Thanks for your help!

Answer 1

Well, first of all, that depends very strongly on which DC motor you're using. There's tons of them, all with different output shaft types and diameter.

Secondly, the attachments you're looking for are unlikely to be found commercially, you'd likely need to manufacture them yourself. This is because of my next point:

A plain DC motor is a poor choice for this system (and, truthfully, many systems). You have effectively no feedback system (that you've mentioned), so you don't know in your code how far the motor has moved. You can estimate with some measurements, but it's usually very inaccurate. You're not going to be able to move the arm in any sort of reliable manner with a plain DC motor. You'll also have no way to "hold in place", as there's no holding torque from an unpowered DC motor.

You likely want to look into small hobby RC servos. They're easy to control with Arduinos, have tons of commercial atttachments, are easy to manufacture custom attachments for without metalwork, and cheap. If you need something higher-power, perhaps a stepper motor will work, but you'll likely have the same issues with finding attachments.