BlackJack
The robot hand that deals cards
Skills:
Inverse Kinematics, Arduino, 3D Printing
Objective:
We wanted to build a robot hand that could draw cards with at least 70% success rate, pick up cups, and do it in less than 30 seconds. This is unique in that most robotic manipulators aren't designed to handle and manipulate 2d-planes like a piece of paper.
How it Works
Finger Design
The material for the base arm is brushed aluminum and the hand is made of plastic. We selected aluminum for the price and structural rigidity, while we used the 3d-printed plastic because we could prototype quickly. The other components of the finger were determined around our sensor needs.
Before Contact
Putty is used to connect the force sensing resistor (sensor) to the finger. Latex is used to increase friction because the force sensor would otherwise be too slick.
After Contact
The Force Sensing Resistor has trouble detecting force when flush with a flat surface such as a deck of cards, so putty was also used as the adhesive because it deforms and bends the FSR during contact, but will return to normal when lifted off. Other adhesives we tested were either too rigid or would activate the sensor by holding it deformation when we didn't want it to.
Software and Electronic Design
We wrote our own inverse kinematics functions to control the 5 digital servos (1 for each finger and 3 for the arm). The digital servos were selected for torsional strength and small tolerance of movement. We used a power source to run the 5 servos and used a pressure sensor to know when to stop the finger from moving. Here's the a quick overview of what we did with the code.
