Let’s talk a bit about grippers and actuators.

Most robots whether they are humanoid animal like or industrial will want to pick something up at some point.

if you are shooting for realism then you need to go with a hand with 5 fingers or an animal claw but this all adds to the complexity, cost and weight of the robot.

Just like cartoons like Mickey mouse were made easier to draw by giving him 4 fingers instead of 5 the same could go for your robot .

You may just need some variation of a cheap $5 2 finger pincher device or maybe add a thumb to grab round objects better.

You could use a simple 2 finger magnet hand gripper if you are picking up metal objects.

But the mechanism to make each finger move like a human hand does get fairly complex. Luckily with Arduino boards most of the software to make fingers move on a robot hand is open source and free .

The Barrett Advanced Robotics company makes several interesting robotic products including their BarrettHand ™ which has a sensor in the palm allowing it to be used in an industrial setting and see items in a container and then pick them up with the fingers/hand. Here is a link to their product video for the BarrettHand ™. Perception Palm .

The palm has features like dual cmos cameras, IR range finder, a laser and more along with a very smooth rotation which is shown as it grabs a glass and pours like a professional bar tender.:)