By: Rob Adams on April 1, 2013
Using the cardboard mock up from last week I have been working on the mechanized articulation of the hand. instead of building a brand new remote control system I dissected a cheap remote control taking out the motors and circuit board containing the remote control system.
Initially I was going to replace one of the motors that was came with the car with a servo. As I traced the electronics back I found the motor was a two pin system with only a positive and negative terminal while the servo required three. Initially I believed that if I were to mount only the two pins to the servo I would be able to run it’s direction by reversing the current like the remote control motor bypassing the third pin all together. Because I had taken apart the car I had no way of supplying power to the system, so in order to do so I wired our variable power supply to the circuit board and set the max voltage to around 3 volts which is what the car ran on which was three AA batteries. When I flipped the switch on and began testing the system I was disappointed to find that the servo only twitched because the third pin was actually needed to regulate the motor within the servo. As a result I began to experiment with using the remaining motor wired to the circuit board as a means to create articulation.
Seeing as i only needed to test articulation i only mounted tendons to the bottom of the finger so that I could test the finger’s ability to move via remote control. I then attached one end of the tendon to the wheel mounted to the motor and the other end to the tip of the finger. When I tested this method the motor was able to rotate drawing the tendon around closing the finger. Success! a remote controlled articulating joint. The next step is to experiment with multiple fingers and perhaps a wrist.
here are some pictures of the testing