Slip Ring Assembly

Parallax ping))) Ultrasonic Sensor
Desoldering Braid
Pololu Pulleys
Copper Clamps
Jumper Wires
12V Unipolar Stepper Motor

Civilizations

Africa

Predynastic Egypt [9000 - 4200 BC]

Egyptian [3150 BC - 31 BC]

Tribal (Nile Valley Civilizations)

Modern




Asia

Mesopotamia

Sumerian [5300 - 4100 BC]

Elam [c.3200 - 539 BC]

Akkadian [2300 - 2200 BC]

Amoritian [2000 - 1600 BC]

Babylonian [c.2500 - 1531 BC]

Assyrian [c.1950 - 612 BC]

Hittite [c.1750 - 1180/750 BC]








Persia


Median [728 - 549 BC]


Achaemenid [c.550 - 330 BC]






China




Ancient Chinese [c.2100 - 221 BC]

Imperial Chinese [221 BC - 1911 AD]

Modern Chinese [1911 AD - ]




Japan

Paleolithic Japanese [35000 - 14000 BC]

Jomon [14000 - 300 BC]

Ancient Japan [300 BC - 1185 AD]

Feudal Japan [1185 - 1603 AD]

Edo Japan [1603 - 1868 AD]

Empire of Japan [1868 - 1945 AD]

State of Japan [1945 AD - ]




Siberia

Mongolian [1206 - 1368]

Tribal

Modern




Europe

Greek [c.750 BC - 146 BC/529 AD

Roman [27 BC - 476/1453 AD]

Turkish

Norse

Anglo-Saxon

Napoleanic

Tribal

Modern




North America

Tribal

Modern




South America

Aztec

Incan

Mayan

Tribal

Modern




Australia

Tribal

Modern




Antarctica

Scientific

Arduino + Tiny Vibrate Motor + Pushbutton

Arduino Code

int buttonPin = 3;
int buttonState = 0;

void setup(){
  pinMode(buttonPin, INPUT);
  Serial.begin(9600);
}

void loop(){
  buttonState = digitalRead(buttonPin);
  switch(buttonState){
    case HIGH:
      Serial.println("off");
      break;
    case LOW:
      Serial.println("on");
      analogWrite(9, 123);
      delay(100);
      analogWrite(9,0);
      break;
  }
  delay(100);
}

2.2kΩ Resistor

Arduino + Pushbutton

Arduino Code

int buttonPin = 3;
int buttonState = 0;

void setup(){

pinMode(buttonPin, INPUT);
Serial.begin(9600);

}

void loop(){

buttonState = digitalRead(buttonPin);
switch(buttonState){

case HIGH:
Serial.println("off");
break;
case LOW:
Serial.println("on");
break;

}
delay(100);

}

QED by Richard Feynman

QED: Quantum Electrodynamics / Quod Erat Dictum

Everyday properties of light:

• goes in straight lines 
• bends when it goes into water 
• when reflected from a surface like a mirror, the angle at which the light hits the surface is equal to the angle at which it leaves the surface 
• light can be separated into colors 
• you can see beautiful colors on a mud puddle when there is a little bit of oil on it 
• a lens focuses light 
• light is partly reflected in some surfaces, such as glass or water

Proven using photomultipliers (which produce an audible click each time a photon hits) and monochromatic (red, green, or blue) light:

• light is made of particles (photons) 
• partially reflective surfaces return an average of 4% of photons 
• as the thickness of a given partially reflective surface increases, the return oscillates between 0 and 8% 
• because glass has two reflective surfaces (front and back), the return oscillates between 0 and 16% 
• this cycle repeats itself at different rates for different colors, so some thicknesses return only red or only blue, or blue and red in different proportions, creating effects like rainbows in oil puddles 

Grand Principle:
The probability of an event is equal to the square of the length of an arrow called the "probability amplitude." An arrow of length 0.4, for example, represents a probability of 0.16 or 16%.

General Rule for drawing arrows if an event can happen in alternative ways:
Draw an arrow for each way, and then combine the arrows ("add" them) by hooking the head of one to the tail of the next. A "final arrow" is then drawn from the tail of the first arrow to the head of the last one. The final arrow is the one whose square gives the probability of the entire event.

Derived from the above findings:

• The arrows correspond to a metaphorical stopwatch hand; their direction is determined by the amount of time it takes for them to travel a given distance. When graphed, outliers cancel each other out, so the center of the distribution has the most influence on the final direction of the arrow / path of the light. Thus, light travels along the shortest path, and the angle of incidence equals the angle of reflection. 
• If the scope of the possible paths is limited too extremely, the time of each revolution of the metaphorical stopwatch is too short, so near-identical paths end up scattering. There is a lower limit to the size of a mirror. 
• Scraping away the parts of a mirror that bias one direction biases the light towards the opposite direction, making a previously unreflective surface reflective. This is called a diffraction grating.

Magnetix Micro

Tiny Round Vibrate Motor

Supplier (Hobby Engineering)

Illuminated Push-On-Off Button

Supplier (Radio Shack)

Linescan Imaging Sensor Module

Supplier (Jameco)

SPST Momentary Button

Supplier (Radio Shack)

16x2 Parallel LCD Display

5x7 Dots
Yellow LED Backlight
3.9x0.9" display
4.8x1.7x0.6" module
5V input
Supplier (Jameco)
Datasheet (658988)

Tutorial: http://arduino.cc/en/Tutorial/LiquidCrystal
You've shorted two of these by wiring them backwards: be careful. The pin towards the middle of the board is Pin 1, Ground.

Hierarchy #1

Chromatics (of Materials)

Chemicals mixed into pigments work by absorbing some light and reflecting the rest.

Arduino + Unipolar Stepper Motor + ULN2004A + Bipolar Stepper Motor + L293DNE + 2 Potentiometers

Arduino Code

#include <Stepper.h>
#define biSTEPS 200
#define uniSTEPS 400
int last_verti, curr_verti, last_horiz, curr_horiz;

Stepper bi_stepper(biSTEPS, 7, 6, 5, 4);
Stepper uni_stepper(uniSTEPS, 8, 9, 10, 11);

void setup(){

Serial.begin(9600);
bi_stepper.setSpeed(15);
uni_stepper.setSpeed(15);

}

void loop(){

sweepVertical();
sweepHorizontal();

}

void sweepVertical(){

bi_stepper.step(10);
bi_stepper.step(-10);
delay(100);

}

void sweepHorizontal(){

uni_stepper.step(20);
uni_stepper.step(-20);
delay(100);

}

void controlVertical(){

curr_verti = analogRead(0);
if(abs(curr_verti - last_verti) > 20) blinkLed();
else bi_stepper.step(curr_verti-last_verti);
last_verti = curr_verti;
delay(100);

}

void controlHorizontal(){

curr_horiz = analogRead(1);
if(abs(curr_horiz - last_horiz) > 20) blinkLed();
else uni_stepper.step(curr_horiz-last_horiz);
last_horiz = curr_horiz;
delay(100);

}

void blinkLed(){

digitalWrite(13, HIGH);
delay(100);
digitalWrite(13, LOW);

}

Color Constancy

In an image employing a limited palette, the gray or neutral areas will take on the appearance of the missing colors.

Chromatics (of Language)

Hue
The color's place in a given color scale.

Saturation
The purity or intensity of the color; the amount of pigment:oil.

Brightness

Shade
The amount of black in the color.

Tint
The amount of white in the color.

Chromatics (of Human Perception)

The retina contains cells called rods & cones.

There are three types of cones:

• S (short-wavelength) ~420nm, violet
• M (middle-wavelength) ~534nm, green
• L (long-wavelength) ~563nm, yellowish green

Colors stimulate each cone type in different proportions—
each color accorded a tristimulus value.
The set of all possible tristimulus values yields the visible color space (10 million colors).

There is one type of rod:
Rods are only informative in dim light,
when the cones are understimulated.

The brain processes tristimulus values into three opponent channels:

• red-green
• blue-yellow
• black-white (luminance)

Art Lessons from Humans (Painting)

Mrs. Ibreck (Lady Eden’s Girls School, 1989-1992)
Use linseed oil to thin
Use turpentine to clean
Lightly sketch out the desired image
Paint the highlights, then the colors, then the shadows
Repeat until image is aesthetically pleasing

Mr. Harris (Latin School, 1997-2001)
Start with a large bristle brush
Then use incrementally smaller bristle brushes
Switch to large soft brush
Then use incrementally smaller soft brushes

The face has cool undertones across the forehead and chin
And warm undertones across the cheekbones and nose tip

The human body tip-to-toe is the height of eight heads
The wingspan is equal to the height
The eyes are halfway between the top of head and bottom of chin
The nose is halfway between the center of eyes and bottom of chin
The mouth is halfway between the bottom of nose and bottom of chin
The head is egg-shaped


Samin Lama (Bhaktapur, Nepal, 2007-2008)
To prepare a thankga canvas:

Build a frame of four interlocked planks of wood wide enough to be rigid under pressure
Cut a canvas a hand-width narrower than the frame’s interior
Sew a finger-width hem around the canvas
Run twine through the hem, crosshatching over the corners of the frame
Use a leather needle to sew the canvas into the frame
Use a stitch four-fingers wide
Stretch the canvas tight and even into the frame, like a hide
Lap around until the canvas is stiff and springy
Bring a small pot of water and a hand-sized strip of animal skin glue to a boil over low heat
Do this outside, because it will stink
When the glue melts, add a fistful of clay
Stir over heat until it is smooth and spreadable, not too sticky
Add small amounts of clay and water as necessary
Lay the canvas on the ground with something clean but expendable, and rigid
We used plywood but cardboard works well
Take a rag and spread the warm primer evenly across the canvas
Take a smooth stone and rub the primer into the canvas
Apply firm pressure, using your whole arm
Flip the canvas over and repeat
Let dry between layers
Repeat until the surface is smooth and thin, like parchment

Don’t breathe while the brush is on the canvas
(This also applies to soldering)

Time breaths with brushstrokes

Use no more paint than necessary
The image should shine clearly when back-lit

Ignore any distraction

Maintain posture


Sara Bright (UC Berkeley, 2007-2009)
[Mr. Harris'] bristle/soft brush strategy is not always best
Use the brush that best suits the attitude of the subject

Keep all your tools clean

Maintain a lightness


Squeak Carnwath (UC Berkeley, 2007-2009)
Paintballs are too violent and ugly to be called painting

To paint carelessly is to insult the entire history of painting

Mineral spirits are better than turpentine as a subtractive
And can be used as a non-retarding thinner

Unprimed canvases deteriorate after 10 years

Paint well-applied can disguise itself as any other medium


Katherine Sherwood (UC Berkeley, 2007-2009)
[Cannot yet be sufficiently summarized.]

Art Lessons from Humans (Photography)

My Father

Never have the subject directly centered

Use the right camera for the right job

Aperture is the dilation of the lens

Shutter speed is the length of time the lens is open, in tenths of a second

Focal point marks the distance from you to the subject

Ms. Ross (Latin School, 1997-2001)

Three ways to take a photo:

Fully com/posed

Right place, right time

Premeditated composition, waiting for the perfect moment

A tight aperture (high number) has a long depth of field (more is in focus)

A wide aperture (low number) has a short depth of field (less is in focus)

To prepare black & white film:

With your hands in a lightproof bag (even darkroom light will ruin undeveloped film)

Use a bottle opener to pry open the film canister

Slide the film onto the ridged spool of the developing tank

Encase the spool in the lightproof tank

Add chemicals and water as directed into the tank

Shaking carefully

Disposing of chemicals properly

Practiced, takes 5 minutes

Developed film is light-safe

To prepare color or slide film:

Is too difficult and not worth doing yourself, send them to a lab

To print on an enlarger:

Any errant light will ruin photo paper

Objects placed directly on paper will produce an image (Rayographs)

Place negative in holder, focus

Place photo paper on enlarger rack

Expose light (time is critical: longer exposure leads to a darker image)

Dodge and burn as necessary

Put photo paper in developer for around 30 seconds (time is critical, may vary)

Then stop bath for a minute (time not critical)

Then fix for four minutes (time is critical, may vary)

Then rinse for a minute (time not critical, image is now light-safe)

Then hang to dry (let dry fully)

Final prints should range from full black to full white

Digital photos are the wave of the future

Art Lessons from Humans (Drawing)

Mr. Bough (Latin School, 1997-2001)
“Draw what you see, not what you know”
“Look at the subject 90% of the time, the drawing 10%”
“Move your entire arm as you draw”
“Erasers are more dangerous than heroin”
"Draw one eyebrow hair at a time"
"Heads are egg-shaped"

Perspective / Vanishing point
Foreshortening
Golden Ratio

Nora Salzman (Latin School, 1997-2001)
Drawing pencils are unnecessary; any implement will do
Practice frequent, casual drawings

Art Lessons from Robots

Mr. Springs (robot, built 2008)

Acrylic paint dries in a matter of hours
Especially the cheap generic kind you bought
Nothing comes of putting down globs of primary colors

Straight out of the bottle
Onto a pre-stretched, pre-primed canvas
And hoping the robot mixes them well

Colors must be coaxed gently through hue and tone
Never applied unmixed
And all rough materials must be selected and prepared
With time and care
(Well, most of this came from the visibly distraught
Squeak and Katherine during my formal critiques)

But the sound he made, like snoring, was sweet
And everyone liked the way his box body twitched from the servos



Nila (robot, built 2008) 

Colors mix unpredictably
Linseed oil retards drying

and spatters
and is hard to clean

Mineral spirits seep through layers and canvas
Plain Ivory soap is good for getting paint out of things
Act on it quickly
Light is a noisy signal,
but slow to change in an empty room
A light sensor left in the dark will see random noise
And Nila alone in the dark,

jittering around the still-wet paint from the day,
and the days before, smearing the information together,
sort of seems to be dreaming

Calculina (AI, built by Tom Lippincott 2010)

Random strokes coupled with a simple feedback mechanism will converge on a desirable result

UNIX Commands

change directory
cd \find_this_directory/sub_directory
/this_directory/sub_directory

list files
ls

list permissions
ls -l

change permissions
chmod -permission filename.ext
r, w, x (read, write, execute)

The Four Laws of Thermodynamics

0. About thermal equilibrium
If two thermodynamic systems are separately in thermal equilibrium with a third, they are also in thermal equilibrium with each other.

1. About the conservation of energy
The change in the internal energy of a closed thermodynamic system is equal to the sum of the amount of heat energy supplied to or removed from the system and teh work done on or about the system. So, we can say (1) “Energy is neither created nor destroyed.”

2. About entropy
The total entropy of any isolated thermodynamic system always increases over time, approaching a maximum value or we can say, “In an isolated system, the entropy never decreases.” Another way to phrase this: Heat cannot spontaneously flow from a colder location to a hotter area— work is required to achieve this.

3. About the absolute zero of temperature
As a system asymptotically approaches absolute zero of temperature all processes virtually cease and the entropy of the system asymptotically approaches a minimum value; also stated as: “the entropy of all systems and of all states of a system is smallest at absolute zero” or equivalently, “it is impossible to reach the absolute zero of temperature by any finite number of processes.” Absolute zero, at which all activity would stop if it were possible to happen, is -273.15°C, or -459.67°F, or 0K.

Lever

From French lever, “to raise”

A rigid object used with an appropriate fulcrum to realize a mechanical advantage.

Archemides said:
“Give me a place to stand, and I shall move the Earth with a lever.”

The ratio of the force applied to each end points of the lever is proportional to the ratio of the length of the lever arm measured between the fulcrum and the force’s application point at each end.

M = Fd

where M is the moment, F is the force,

and d is the distance between the force and the fulcrum

F*L_F = R*L_R

where F is the force, L_F is the distance between the application and the fulcrum

R is the resistance, and L_R is the distance between the resistance and the fulcrum

Class 1: The fulcrum is located between the applied force and the load

Class 2: The load is located between the fulcrum and the force

Class 3: The force is located between the fulcrum and the load

Pulley

Reasons to use a pulley:

• Change the direction of an applied force 
• Transmit rotational motion 
• Realize a mechanical advantage in either a linear or rotational system of motion

Pulleys are composed of a wheel on an axle or shaft
that may have a groove between two flanges along the edge

A rope, cable, belt, or chain usually runs over the wheel and inside the groove
if present.

Belt and pulley systems transmit mechanical power, torque, and speed across axes, and if the pulleys are of differing diameters, realize a mechanical advantage.

Rope and pulley systems transmit a linear motive force (in tension) to a load through one or more pulleys for the purpose of pulling the load.

A fixed pulley has a fixed axle
and is used to change the direction of the force on a rope
and has an MA = 1

A movable pulley has a free axle
and is used to multiply forces
and has an MA = 2

A block and tackle system uses a combination of fixed and movable
and has an MA > 2

Mechanical Advantage

MA = output force / input force

MA = distance over which effort is applied / distance over which the load is moved

Gear

Reasons to use a gear:

• Reverse the direction of rotation 
• Change the speed of rotation 
• Move rotational motion to a different axis 
• Keep the rotation of two axes synchronized 

Gears are read left-to-right when counting ratios (left gear is bigger in a 2:1).

Gears are manufactured such that tooth count is more accurate than circumference in determining gear ratios.

To create large gear ratios, use a gear train.

Worm gears function as “one tooth” gears
and flip the axis of motion 90°.

A planetary gear system uses the same axis for both input and output gear
and is very rugged.

Rotation (Torque)

A twist that causes a perpendicular body to rotate.

Thrust (Force)

A push or pull that causes a free body to accelerate.

Resistor

Req = Equivalent Resistance

In Series

Req = R1 + R2 + R3 + ...

In Parallel

1/Req = 1/R1 + 1/R2 + 1/R3 + ...

Black	Brown	Red	Orange	Yellow	Green	Blue	Violet	Grey	White
0	1	2	3	4	5	6	7	8	9

(ex. Brown Black Red = 1000 = 1KΩ)

Ohm's & Joule's Laws

V = Electric Potential Difference (Volts)
I = Current (Ampere)
R = Resistance (Ohms)
P = Power (Watts)

V = I/R

P = IV

P = V2/R

P = I2/R

Potentiometer

Arduino Code

void setup(){
Serial.begin(9600);
}

void loop(){

Serial.print("Value: ");
Serial.print(analogRead(0));
delay(100);

}

Arduino + Unipolar Stepper Motor

Arduino Code (Back & Forth)

#include <Stepper.h>
#define STEPS 400 //360° divided by step angle

Stepper stepper(STEPS, 8, 9);

void setup(){
stepper.setSpeed(30); //RPMs
}

void loop(){

stepper.step(100);
delay(100);
stepper.step(-100);
delay(100);

}

Arduino Code (Back & Forth)

#include <Stepper.h>
#define STEPS 400 //360° divided by step angle
Stepper stepper(STEPS, 8, 9, 10, 11);

void setup(){
stepper.setSpeed(30); //RPMs
}

void loop(){

stepper.step(100);
delay(100);
stepper.step(-100);
delay(100);

}

Arduino + Bipolar Stepper Motor

Arduino Code (Back & Forth)

#include <Stepper.h>
#define STEPS 200 //360° divided by step angle
Stepper stepper(STEPS, 9, 10, 11, 12);

void setup(){

stepper.setSpeed(30); //RPMs

}

void loop(){

stepper.step(100);
delay(100);
stepper.step(-100);
delay(100);

}

L293DNE Dual H-Bridge

Supplier (Jameco)
Datasheet

PNP Transistor

NPN Transistor

Emitter Base Collector

Supplier (Jameco)

Datasheet (2N3904)

ping))) Ultrasonic Sensor

const int pingPin = 7;

void setup(){

  Serial.begin(9600);

}

void loop(){

  long duration, inches, cm;

  pinMode(pingPin, OUTPUT);

  digitalWrite(pingPin, LOW);

  delayMicroseconds(2);

  digitalWrite(pingPin, HIGH);

  delayMicroseconds(5);

  digitalWrite(pingPin, LOW);

  pinMode(pingPin, INPUT);

  duration = pulseIn(pingPin, HIGH);

  inches = microsecondsToInches(duration);

  cm = microsecondsToCentimeters(duration);

  

  Serial.print(inches);

  Serial.print("in, ");

  Serial.print(cm);

  Serial.print("cm");

  Serial.println();

  

  delay(100);

}

long microsecondsToInches(long microseconds){

  return microseconds / 74 / 2;

}

long microsecondsToCentimeters(long microseconds){

  return microseconds / 29 / 2;

}

Supplier (Jameco)

47Ω Resistor

Supplier (Maplin)

3V DPDT Relay

Supplier (Radio Shack)

7-Segment LED

LED (Light Emitting Diode)

Jumper Wires

Supplier (Sparkfun)

Diode

Electricity can pass from silver to black, but not black to silver.

Breadboard

Supplier (Carnegie Mellon University's Fun With Robots Club)

The input pins on a breadboard are connected row-wise, divided by the gutter; i.e. 1A-1E are connected.

The power pins are connected column wise: canonically the blue column is ground and the red, source.

AA Battery Holder

9V Battery Holder

Arduino Duemilanove

Supplier (Sparkfun)
Developers' Site

Accelerometer ADXL335

Supplier (Sparkfun)

Atomic Number

Symbol is Z.

Equals the number of protons in a given atom.

Each unique atomic number corresponds with an element on the periodic table.

Proton

Symbol is p+.

Subatomic particle with electric charge of +1e.

Mass is 1.672621637(83) * 10-27kg.

Exists as a nucleon in all atoms.

Exists independently as the hydrogen atom, H+.

Number in each atom (atomic number, Z) determines its element.

Composed of two up quarks and one down quark.

Quarks

Symbol is q.

From James Joyce, Finnegans Wake

“Three quarks for Muster Mark!”
Three being a natural organizational number for quarks,
color is also employed as a metaphor.

Elementary particle.

Never exist independently.

Up Quark
Symbol is u.

Elementary particle with electric charge of +2⁄3e.

Have gravitational, electromagnetic, weak, and strong interactions.

Stable quarks.



Down Quark
Symbol is d.

Elementary particle with electric charge of -1⁄3e.

Have gravitational, electromagnetic, weak, and strong interactions.

Stable quarks.

The Four Known Fundamental Interactions

Electromagentism
Causes interaction between electrically charged particles
in areas called electromagnetic fields

And binds (negative) electrons to (positive) protons

which together form atoms
which together form molecules
which are categorized as elements
which together form chemicals
which together form everything we see

A changing electric field generates a magnetic field

and vice-versa
in a process called electromagnetic induction

Strong Interaction
Causes the (netural) neutrons to bind to the (positive) protons and form the nucleus

and quarks to bind to gluons and form nucleons, etc
overriding electromagnetism
The strongest of the Interactions

Weak Interaction
Causes radioactivity through beta decay
(the emission of electrons by neutrons or positrons by the protons in atomic nuclei)

And is due to the exchange of the heavy W and Z bosons



Gravitation
Causes dispersed matter to coalesce

And is due to the curvature of spacetime which governs the motion of inertial objects

Newton's simpler, still reliable theory states:

I deduced that the forces which keep the planets in their orbs must [be] reciprocally as the squares of their distances from the centers about which they revolve: and thereby compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the Earth; and found them answer pretty nearly.

MCMC (Markov Chain Monte Carlo)

A class of algorithms used to find the probability distribution of an event given the probabilities of causally linked events.

Random walks are taken through the causal chain,

the results of these walks eventually converging on a stationary distribution within an acceptable margin of error.

Combinatorics

nCr : "from n choose r"

n = length of possibility set (ex. 5 letters)
r = length of combination set (ex. pick 2)



Permutation with Repetition
Order matters and elements of the possibility set can be repeated.

nr

	a	b	c	d	e
a	aa	ab	ac	ad	ae
b	ba	bb	bc	bd	be
c	ca	cb	cc	cd	ce
d	da	db	dc	dd	de
e	ea	eb	ec	ed	ee

Permutation without Repetition
Order still matters, but elements cannot be repeated.

n!
(n-r)!

	a	b	c	d	e
a		ab	ac	ad	ae
b	ba		bc	bd	be
c	ca	cb		cd	ce
d	da	db	dc		de
e	ea	eb	ec	ed

Combination without Repetition
Order does not matter, and elements cannot be repeated.

n!
r!(n-r)!

	a	b	c	d	e
a		ab	ac	ad	ae
b			bc	bd	be
c				cd	ce
d					de
e

Combination with Repetition
Order does not matter, but elements can be repeated.

(n+r-1)!
r!(n-1)!

	a	b	c	d	e
a	aa	ab	ac	ad	ae
b		bb	bc	bd	be
c			cc	cd	ce
d				dd	de
e					ee