I just wanted to share this idea to make a simple, cheap robotic hand (or any end effector) using only one motor.
Using only ONE motor for the whole hand allows the hand to be:
- extremely cheap, which is good for your wallet because usually servomotor are quite expensive
- extremely light, which is good for your project because usually the main problem of an end effector is to be too much heavy, because the distance from the center of gravity of the robot multiplies its weight.
Of course, if you need to make a complex animatronic hand, capable of moving each finger individually, there's no choice, you will need a motor for every finger/ group of fingers you want to move separately.
But, if you want to make a simple but effective end effector for your DIY robot, probably you should consider the idea of using just one motor for the whole hand!
In the video above you can see how the hand is made, and some test of the gripper.
I hope this can be useful to somebody!
FAQ (under construction):
The diameter of the hose is 1.5 cm.
The thickness of the hose is approximately 3mm for thumb, index, middle, and 2mm for ring and pinkie (if you see the video if can recognize two different kind of hoses). This is because a thicker hose is harder to pull, but is more effective to create the opposable thumb mechanism.