Week of Nov 11

Meetings:

Nov 14

Members present: Usama, Steven, Dat

We discussed two different design options for the knuckle. The new design will build off of the advantages of both by incorporating a "fork" that will help to align the tension strings that will ultimately keep the Arduino hand in an open palm position when not being interfaced by the analog input. The existing design will have to be updated to accommodate this combination.

The Arduino code was also discussed. In general, mapping the flex sensors to the servos will be a relatively simple task. The difficulty arises in how we will decide to have the glove interact with the servos from a distance, perhaps remotely i.e. how we decide to connect the electronics to the mechanism. More research is required.

We also discussed the issue of power consumption, since we will need five servos running independently at one time. We aren't sure of whether this is an issue of voltage or current draw. In any case, this has been put on the backburner, and can be worried about later.

For this upcoming weekend, research on IR or RF transmitters and receivers will need to begin, as well as ideas on the control glove and mounting the Arduino and flex sensors. We will also have to determine how far we go with the thumb design (how intricate will it's motion be?).

Nov 12

Members present: Kendrick, Dat

Today we discussed the design of the knuckles, as well as the overall design of the entire assembly, which included choosing materials, costs, etc. One concern was whether the stock servo motors that came with the SparkFun kit would have enough torque to control the fingers. Kendrick will determine if these servos provide enough torque and get back to the rest of the group.

Weekly Progress:

Dat

Time spent: 4-5 hours

I made some initial designs of the knuckle and eventually came upon a design that would accomplish everything we needed it to do in terms of replicating a real human hand's opening and closing motion. It took some time to determine how excess material could be shaved off the part, since we are only given 4 cubic inches of material to work with. Show below is the part and its dimensions.

Knuckle Part File

Knuckle Drawing File

This part was designed with the intention of taking two identical pieces, rotating them 180 degrees so that they face each other, and then insert a pin to connect them. The part is made to sit flush against the end of a 5/8 inch dowel, and attach by using a countersunk wood screw, perhaps around the size of #4 and 1/2 inch depth. 

The group discussed the issue of aligning the tension strings along the length of the fingers whenever the fingers would close. This design did not take that into account, but we did come up with the idea of adding a sort of "fork" that would be at the top of this component. Whenever the hand closes, the fork is lifted, and the string will stay aligned. Further implementation of this concept in combination with the above design will be required this weekend.

I also spent time determining the best materials to use. In general, the fingers will be something along the lines of 1/2 inch to 3/4 inch wooden dowels, cut down to size. 5/8 inch is about the diameter of my fingers, so that is how I designed the knuckles. I also found some elastic band at a JoAnn Fabrics. It's much more springy than elastic thread, but not as strong as elastic cord. It's a good in-between stretchiness that I believe will work when keeping the hand open when not being controlled. It should also be weak enough for some servo motors to pull against when closing the fingers.

The wooden dowels, the elastic bands, and wood that will be the palm and forehand will be the cheapest materials, probably all under $20. I would guess that the electronics (more flex sensors and servos if it so happens that we need them) will be the most expensive. We estimated that the whole project could cost around $100.

Kendrick:

Time spent: 2 hrs

I looked into what type of glove should be used. It was decided that a standard glove would by insufficient and too weak, whereas a mechanic's glove would be stronger and better. I got yellow and black DeWalt's mechanical glove that will be used for the hand. Our group also wanted to find out if the servos provided in the SIK would be sufficient enough to use with the strings, in terms of strength. I will perform a torque test on the servos and decide whether or not they will work.

Steven:

Time spent: 2-2.5 hrs

Over the weekend I looked into possible configurations for the control glove as well as possible ways to mount the thumb to the base piece. The most prominent thing we need to decide for that is if we want the thumb to have full range of motion or if it should only be able to bend inwards. 

Usama

Time spent: 2 hrs

After the initial meeting, it was determined that I would effectively be in charge of the Arduino code which would interface and run the Master Hand system. As such, I began by brainstorming and imagining various ways in which I could approach the task, thinking of what some of my potential options might be for assembling the code.

Our initial discussions had entertained the idea of a remote control with presets for the hand configuration as well as having the human interfaced glove which would allow for active participation and an analog input that would be more dynamic. After some thought, I determined that I would pursue the dynamic hand code more aggressively and see if there was any time left to add an additional remote control for preset figures.

In terms of the dynamic glove input, I categorized and wrote out a brief outline that detailed some initial thoughts:


     Glove:

• Five Sensor Variables 
• Five Servo State Variables
• Five Servo Value Variables
• Map each of these separately.
• How will we communicate glove to hand? Wired or wireless?

     Remote:

• Maintain each servo variable (independent of functions) 
• Map each servo according to sub function? 
• Each servo controlled by if function of buttonstates? 

      ** Also need RF Transmit Code


Based off of this template, I began to explore a pseudocode that would provide a template that I could further pursue in building the code for the Master Hand system.