how the fingers work

the fingers are moved using wires and tension.

each finger is looped through with a wire/string/line in a top-bottom fashion.

when the top wire is loosened/bottom wire is tightened, the finger curls in its joints, resulting in a "bent finger".

you don't have precise control of each joint movement, but it is simple enough to be controlled by a single actuator (in this case a servo).

here is me just using my own hands as an actuator:

here it is hooked up to as servo and controlled by a potentiometer:

the movement is not smooth because
1) it's controlled by a potentiometer that I am controlling, as seen in the background, and I was unable to move it all the way with one smooth finer motion.
2) the tension in the line was not entirely tight. I need to learn how to tie these well.

now I have a get a bunch of servos.

much credit and thanks to Inmoov once again.

Comments

duty cycle testing

Now that I saw a physical response, I should try to make it similar to how a servo should be controlled. Servos are actuators that receive (expect) position input (as opposed to motors, which receive speed/intensity input). Simply put, it registers input as pulses, decoding the ratio of high (a "on" signal) to low in a given period as a position value. A better explanation : http://learn.adafruit.com/adafruits-raspberry-pi-lesson-8-using-a-servo-motor/servo-motors As I am waiting for my servo to be shipped, I will continue to work with the LED light. As opposed to my previous setup of having the light turn on every time the request is given, I will have the light turn on and off in a regular pattern until a request is given, upon which the pattern will change for one "cycle" (on-and-off pair). The on-and-off logic (previously the LED control logic) will be run in a separate thread: def dCycle(*args): global dCVal ...

dabbling with android

I've been wanting to dabble with Android development recently, and yesterday I realized that there is a Socket.IO client API available for Java/Android. The API is pretty straightforward, so I loaded a test Android project I had made for going through Android basics and connected to the OpenSesame Node server. and it works! I mean, the interface is non-existent and it's really just bare-bones, but having the servo respond through an Android application was pretty refreshing. (the web client and the android client "communicating" with each other--messaging is pretty much for debugging purposes)

playing with servos

some servos that I had ordered were delivered. the instructions suggested another brand/model of servos, but these were a much more economical (cheap). I tried adding them to the hand: I'll have to print the "pulley" pieces that will be attached to the servos. meanwhile, I did somewhat (hackily) got the wrist to work, for now: you keep hearing the "usb plugged out" sound in the background, and that's because the servo was being powered by the arduino. the servo's power draw appears to be causing a shutdown of the device. will need a better power source for the servos. it feels like these pieces that are supposed to be plugged into the servo will have size issues.

the quest for robots

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