Arduino 102

/ / digital in-digital out

Buttons
LEDs
Motors

These little switches are a 1/4" on each side, and can plug directly into a breadboard. These mechanical devices have 4 legs, which may make you think that there are 4 wires that are switched on and off, but in fact, two on each side are actually connected together inside. So really, this switch is just a 2-wire switch.

Normally, the two wires are disconnected (normally open) but when you press the little button on top, they are mechanically connected.

To get the buttons to sit better in the protoshield, you may want to straighten out the legs (just squish them with a pair of pliers) so that they look like the button on the left.

Adding the Microcontroller

Now connect the led and the switch to the chip:
NO Push button

The Arduino chip has uncommitted inputs. That is, when an I/O pin is not connected and acting as an input, it cannot be assured to be either HIGH or LOW. Pull-up and pull-down resistors are needed to commit the input to the non-active (open) state for switches.

When the button IS NOT pressed (open), P10 will sense Vss (0V, LOW, 0) because it is pulled-down to Vss.
When PB1 IS pressed (closed), P10 will sense Vdd (5V, HIGH, 1) making it Active-High.

/* using a push button*/
int LED1=8;
int BTN1=10;
void setup(){
    pinMode(LED1,OUTPUT);
    pinMode(BTN1,INPUT);
}
 void loop(){
 if (digitalRead(BTN1)==0){
        digitalWrite(LED1,LOW);
     } else if  (digitalRead(BTN1)==1){
        digitalWrite(LED1,HIGH);
     }
 }

This code can be rewritten:

/* using a push button*/
int LED1=8;
int BTN1=10;
void setup(){
    pinMode(LED1,OUTPUT);
    pinMode(BTN1,INPUT);
}
 void loop(){
 if (!digitalRead(BTN1)){
        digitalWrite(LED1,LOW);
     } else if  (digitalRead(BTN1)){
        digitalWrite(LED1,HIGH);
     }
 }

or:

/* using a push button*/
int LED1=8;
int BTN1=10;
void setup(){
    pinMode(LED1,OUTPUT);
    pinMode(BTN1,INPUT);
}
 void loop(){
     digitalWrite(LED1,digitalRead(BTN1);  
 }

LEDs

LEDs are cool because they're tiny and long lasting (up to 10 years). Unlike incandescent bulbs, LEDs don't get hot. They also don't consume a lot of power.

LEDs come in many colors, brightnesses, sizes and shapes.

LEDs are polarized. The positive side (the side connected with the + side of the battery) is the longer leg and is referred to as the anode. The shorter leg, the negative side, is called the cathode. You won't hurt the LED if you accidentally plug it in backwards. It just won't work.

The color of an LED is determined by the semiconductor material and not by the package (plastic body). Different colored LEDs require different amounts of voltage to light up. Red, green, and yellow LEDs typically require 2.2V-2.4V. Super-bright white and blue LEDs can require up to 3.4V.The optimum voltage is referred to as forward voltage (V_F).

Most LEDs require 20mAh of current flowing from the battery. Most batteries supply more than 20mAh, so you need to use a resistor to limit the flow of current to each LED so it won't burn out.

V_F Forward Voltage is also referred to as Voltage Drop. It is the minimum amount of voltage needed to light up an LED.

l_V Luminous Intensity is the amount of light emitted from an LED in a particular direction. It is measured in millicandela (mcd). You can consider this property as brightess. The greater the millicandelas the brighter the LED.

I_F Forward Current is the amount of current the LED uses.

Viewing Angle is the spatial distribution or spread of light. It is expressed in degrees that measure the width of the light beam. LEDs with a small viewing angle produce a more focused beam, and LEDs with larger viewing angles produce a softer more dispersed beam.

Type	Color	I_F	V_F Typ	V_F Max	Luminous Intensity	Viewing Angle	Wavelength
Standard	Red	30mA	1.7V	2.1V	5mcd@10mA	60°	660nm
Standard	Yellow	30mA	2.1V	2.5V	32mcd@20mA	60°	565nm
Super bright	Red	30mA	1.85V	2.5V	500mcd@20mA	60°	660nm

UV LED's emit a light that you don't see, but that can damage your eyes. Be careful!

To use a resistor calculator you need the following information:

Supply voltage, the voltage from your power source
LED voltage Drop
LED Forward Current
Number of LEDs you want to connect
Connection— whether the LEDs are connected in series or in parallel

There are 3 ways to connect LEDs together:

In parallel—each positive lead is connected to the positive lead of the next LED, and each negative lead is conected to the negative lead of the following LED.
In series—each positive lead of an LED is connected to the negative lead of the next LED.
Separate LED chains—chains of LEDs wired together in parallel can be combined all together in series

The decision to wire LEDs in series versus in parallel depends mainly on the following factors:

the power source
the number of LEDs
whether you are using different colored LEDs together

Parallel—LEDs wired together in a parallel circuit work great if you need to string together a number of same-colored LEDs and have them powered by a small voltage source.

Electricity takes the path of least resistance If you have two different colored LEDs, one red with a forward voltage of 2.2V and the other green with a forward voltage of 2.4V, the current will flow through and light only the red LED. The green LED will be circumvented. It is possible to mix colored LEDs with the same specifications in a parallel circuit, but often some of the LEDs end up appearing dimmer than the others.

When LEDs are connected in parallel, the voltage across each LED remains the same, and the current is divided between them.

A circuit with a 3V battery and a resistor will light up 2 red LEDs with forward voltages of 2.2V when wired in parallel. Each LED will receive its 2V and the current will be dispersed between the two LEDs—therefore, you'll drain your battery more quickly than if you had wired them in series.

When resistors are connected so that the same voltage is applied across each resistor, the resistors are said to be connected in parallel. The single equivalent resistance R of three parallel resistors can be determined from:

1/R_total=1/R1+1/R2+1/R3

A connection of two resistors in parallel is called a current divider

In series— When LEDs are connected in series, the voltage is divided equally across each LED, and the current remains the same. If you had a series circuit with a 3V battery, a resistor and 2 red LEDs with forward voltages of 2.2V, neither would light up as each would receive only 1.5V.

When resistors are connected in a circuit so that the same current flows through each resistor, the resistors are said to be connected in series. It is possible to determine the resistance of a single resistor that has the same resistance as a number of resistors in series. This single equivalent resistance is just the sum of the individual resistances. For three resistors in series, the equivalent resistance R is given by:

R_total = R1 + R2 + R3

A series connection of two resistors is called a voltage divider

Connecting different colored LEDs

The power supply must be equal to or more than the sum of the voltage requirements for each LED and its resistor. If you want to mix colors and wire your LEDs in parallel, then you need to add the right resistor to each LED (not one for the entire circuit). This levels the amount of power required to illuminate each LED.

If your project requires the use of multiple LEDS and a small power supply, parallel wiring is the way to go.

Flashing LED

These LEDs contain an integrated circuit. They do not require resistors.

IR LED

These LEDs emit Infrared light that is invisible to the human eye

These are found in remote control devices

Piranha or High-Flux LED

These LEDs are square and have four leads: two are positive and two are negative.To distinguish the cathodes from the anodes you must refer to the LEDs' datasheet or create a simple ccircuit with alligator clips, a battery and a resistor.

Blinking an LED without delay

 /* Blinking LED without using delay*/

// LED should be the pin connected to an LED	
int led = ___;

int btn=____;
int btnVal;
int btnState;
boolean doYourThing=false;

// set value to the state of the LED before the program runs 
int val = 0; 

// store last time LED was updated
unsigned long previousMillis = 0; 

// interval at which to blink (milliseconds)
unsigned long interval = _____;           

void setup(){ 
    // sets the digital pin as output
    pinMode(led,OUTPUT); 
    // sets the digital pin as input
    pinMode(btn,INPUT); 
    btnState=digitalRead(btn);
}

void loop(){
   btnVal=digitalRead(btn);
   
   if(btnVal!=btnState){
       if(btnVal){
           doYourThing=!doYourThing;
       }
   }
   
   if(doYourThing){
      // check to see if the difference between the current time //and last time you blinked the LED is greater than
      // the interval at which you want to blink the LED.
      if (millis() - previousMillis > interval) {
  
          // remember the last time you blinked the LED
          //by setting previousMillis to millis()
          _________________
    
          // if the LED is off turn it on and vice-versa.
          if (val == LOW){
              val = HIGH;
      
          }else{
             val = ____;
          }
      }
  }else{
      val=0;
      
  }
    
    digitalWrite(led, val);
  }
}

Now add a button that acts as a switch:

 /* Blinking LED without using delay*/

// LED should be the pin connected to an LED	
int led = ___;


// set value to the state of the LED before the program runs 
int val = 0; 

// store last time LED was updated
unsigned long previousMillis = 0; 

// interval at which to blink (milliseconds)
unsigned long interval = _____;           

void setup(){ 
// sets the digital pin as output
 _____________ 
}

void loop(){
  // check to see if the difference between the current time and 
  //last time you blinked the LED is greater than
  // the interval at which you want to blink the LED.
  if (millis() - previousMillis > interval) {
  
  // remember the last time you blinked the LED
  //by setting previousMillis to millis()
   _________________
    
    // if the LED is off turn it on and vice-versa.
    if (val == LOW){
      val = HIGH;
      
    }else{
      val = ____;
    }
    digitalWrite(led, val);
  }
}

/ / Transistors

Transistors are used to amplify current. The leads are divided into BASE, COLLECTOR and EMITTER or GAIN.

The GAIN is simply the amount of amplification.

Collector current is always greater than base current, sometimes by many times.

If the collector current of a transistor is 0.12 amps and the gain is 40, what is the base current?

If the collector current of a transistor is 0.4 amps and the base current is 0.002 amps, what is the current gain?

If the collector current of a transistor is 0.5 amps and the gain is 100, what is the base current?

/ /Darlington Transistors and HIGH CURRENT DC DEVICES:

You may want to use the Arduino to control a DC powered device that draws higher current. A solution for this situation is to use an NPN Darlington Transistor designed for medium power linear switching applications.

This component can be used to power devices such as motors, solenoids and fans, where the only necessary operation control operation is ON and OFF.

The base of the transistor (PIN 1) is connected to the Arduino output pin (D6) through a 1K OHM resistor. The emitter (PIN3) is connected to ground and the collector (PIN2) is connected to one end of the coil of the device being driven. The other end of the coil is connected to the +12VDC external power supply (the ground from this power supply is connected to a common ground with the Arduino - this is necessary for the transistor to function).

It is very important to put a diode across the coil of the device being powered to protect the control circuit from a potential voltage spike that can be created when current is released from the device being powered.

The Tip120 transistor can let you to control a high-current DC load such as a DC motor or an incandescent light from a microcontroller.

Parts

Solderless breadboard
hookup wire
Arduino Microcontroller
Light Emiting Diodes, LED
10uF electrolytic capacitor
10Kohm resistors
10Kohm potentiometer
power diodes
(for DC Motor version only)
DC power supply
TIP120
DC Motor - or - Incandescent lamp and socket

Prepare the breadboard

Conect power and ground on the breadboard to power and ground from the microcontroller. On the Arduino module, use the 5V and any of the ground connections:

Add a potentiometer
Connect a potentiometer to analog in pin 0. You'll use this later to control the output, whether it's a motor or a light.

Connect a TIP120 transistor to the microcontroller.
The transistor allows you to control a circuit that's carrying higher current and voltage than the microcontroller. It acts as an electronic switch. The one you're we're using is an NPN-type transistor called a TIP120. It's designed for switching high-current loads. It has three connections, the base, the collector, and the emitter. The base is connected to the microcontroller's output. The high-current load (i.e. the motor or light) is attached to its power source, and then to the collector of the transistor. The emitter of the transistor is connected to ground.

The schematic symbol of an NPN transistor where B is the base, C is the collector, and E is the emitter.

Connect a motor

In the motor circuit below, there is a diode in parallel with the collector and emitter of the transistor, pointing away from ground. This is there to protect the transistor should the polarity of the current reverse (for example, if the motor was turned in reverse, or when it releases back voltage). Be sure to add the diode to your circuit correctly. The silver band on the diode denotes the cathode which is the tip of the arrow in the schematic.

This circuit assumes you're using a 12V motor. Your motor requires 6-9V, so make sure to use the appropriate power supply. The motor and the microcontroller must share a common ground or the circuit won't work properly.

Connect a lamp
Likewise, the lamp circuit below assumes a 12V lamp. Change your power supply accordingly if you're using a different lamp. In the lamp circuit, the protection diode is not needed, since there's no way for the polarity to get reversed in this circuit:

Program the microcontroller

Here's a quick program to test the circuit:

 const int transistorPin = 9;    // connected to the base of the transistor

 void setup() {
   // set  the transistor pin as output:
   pinMode(transistorPin, OUTPUT);
 }

 void loop() {
   digitalWrite(transistorPin, HIGH);
   delay(1000);
   digitalWrite(transistorPin, LOW);
   delay(1000);
 }

Now that you see it working, try changing the speed of the motor or the intensity of the lamp using the potentiometer. Try this code:

 const int potPin = 0;           // Analog in 0 connected to the potentiometer
 const int transistorPin = 9;    // connected to the base of the transistor
 const int potValue = 0;         // value returned from the potentiometer

 void setup() {
   // set  the transistor pin as output:
   pinMode(transistorPin, OUTPUT);
 }

 void loop() {
   // read the potentiometer, convert it to 0 - 255:
   potValue = analogRead(potPin) / 4;
   // use that to control the transistor:
   analogWrite(9, potValue);
 }

Notes

For the motor users:
A motor controlled like this can only be turned in one direction. To be able to reverse the direction of the motor, an H-bridge circuit is required.

/ / Multiple LEDs and Transistors

Each digital pin on the Arduino has an internal pull up resistor that can be turned on and off using the digitalWrite() command when it is configured as an output. When it is HIGH, 5V sent to the pin and can deliver 40mA of current. This is adequate to power an LED, but most devices that you will want to power will require more current. A device that is trying to draw more current than this can cause the Arduino to shutdown and could easily damage the chip. There are many methods to increase the current that can be sources on an output pin. When a relatively small amount of additional current is needed, a 2N3904 NPN Transistor (or any similar type) can be used to accomplish this. In this example, you will connect four LEDs to one output pin using this simple transistor circuit.

Sources:
http://itp.nyu.edu/physcomp/Labs/
Building Wireless Sensor Networks [Kindle Edition] Robert Faludi
Open Softwear
Fashioning Technology: A DIY Intro to Smart Crafting (Craft: Projects) by Syuzi Pakhchyan
www.kpsec.freeuk.com/trancirc.htm http://www.technologystudent.com/elec1/transis1.htm http://www.allaboutcircuits.com/vol_3/chpt_4/1.html

accelerometer	changes in speed	Triple Axis Accelerometer Breakout - MMA7260Q Description: This is a breakout board for Freescale's triple-axis MMA7260QT accelerometer. With a low power shut-down mode, high sensitivity output with selectable ranges (±1.5, 2, 4, and 6g), this was one of the very first sensors to market with three accelerometers built onto a single IC! Board comes fully assembled and tested with external filters installed. The MMA7260QT is a 3.3V part and outputs an analog voltage for each of the three outputs. This voltage is in ratio to the measured acceleration and to the supply voltage (ratiometric). You will need some extra hardware to convert this analog signal to a usable digital one. Luckily, many uCs have a built in Analog to Digital converter.
capacitance	electrical properties often associated with human touch	Description: Breakout board for the Analog Devices 7746 capacitance sensor. Configured for two channels of single-ended capacitance input. Comes with an example touch sensor as well as long capacitance creating traces. Useful as a complete I2C interfaced touch sensor, or as a capacitance measuring tool.
color	color	Color Light Sensor Evaluation Board Description: The ADJD-S371 is a great little sensor. This evaluation board provides all the necessary support circuitry to actually play with the sensor!
flex	angular position and changes	Flex Sensor 4.5" Description: A simple flex sensor 4.5" in length. As the sensor is flexed, the resistance across the sensor increases. Patented technology by Spectra Symbol - they claim these sensors were used in the original Nintendo Power Glove. The resistance of the flex sensor changes when the metal pads are on the outside of the bend (text on inside of bend). Connector is 0.1" spaced and bread board friendly. Check datasheet for full specifications.
force	physical pressure in an analog scale	Force Sensitive Resistor - Small Description: This is a small force sensitive resistor. It has a 0.16" (4 mm) diameter active sensing area. This FSR will vary its resistance depending on how much pressure is being applied to the sensing area. The harder the force, the lower the resistance. When no pressure is being applied to the FSR, its resistance will be larger than 1MΩ, with full pressure applied the resistance will be 2.5kΩ. Two pins extend from the bottom of the sensor with 0.1" pitch making it bread board friendly. These sensors are simple to set up and great for sensing pressure, but they aren't incredibly accurate. Use them to sense if it's being squeezed, but you may not want to use it as a scale.
gas	alcohol, methane, CO2, CO, propane, etc	Alcohol Gas Sensor MQ-3 Description: This alcohol sensor is suitable for detecting alcohol concentration on your breath, just like your common breathalyzer. It has a high sensitivity and fast response time. Sensor provides an analog resistive output based on alcohol concentration. The drive circuit is very simple, all it needs is one resistor. A simple interface could be a 0-3.3V ADC. Features: 5V DC or AC circuit Requires heater voltage Operation Temperature: -10 to 70 degrees C Heater consumption: less than 750mW
gyroscope	rotation	Gyro Breakout Board - LPY530AL Dual 300°/s Description: This is a breakout board for the ST's dual-axis LPY530AL gyro (don't mind the photos). The LPY530AL measures angular velocity along the pitch and yaw axes with a full scale of ±300°/s. Two different analog outputs are provided for both the x- and z- axes - one 1x amplified and the other 4x amplified. A regulated voltage between 2.7 and 3.6VDC should be supplied to the power pins. We have the filtering circuits all set up; you'll just need to connect the outputs to an ADC, and you're ready to go. This breakout board includes the gyro and all necessary filtering capacitors as shown. The 1x and 4x amplified outputs of both axes are connected to the 0.1" pitch headers, along with the power-down, self-test, high-pass filter reset, and power pins.
Hall effect	magnetic fields	Description: The US1881 is an integrated Hall effect latched sensor. That's nice but what does it do? Holding a magnet near the sensor will cause the output pin to toggle. This makes for a robust presence sensor. A reed sensor also works nicely, but can be limited by the glass encapsulation and size. A hall effect sensor is much smaller, but can handle less current than a reed switch. The device includes an on-chip Hall voltage generator for magnetic sensing, a comparator that amplifies the Hall voltage, and a Schmitt trigger to provide switching hysteresis for noise rejection, and open-collector output. An internal bandgap regulator is used to provide temperature compensated supply voltage for internal circuits and allows a wide operating supply range. If a magnetic flux density larger than threshold Bop, DO is turned on (low). The output state is held until a magnetic flux density reversal falls below Brp causing DO to be turned off (high). Features: 3.5V to 24V DC operation voltage Low current consumption Temperature compensation Wide operating voltage range Open-Collector pre-driver 50mA maximum sinking output current Reverse polarity protection Lead Free Package: TO-92
microphone/ acoustic	sound	Breakout Board for Electret Microphone Description: Ready to add audio to your next project? This small breakout board couples a small electret microphone with a 100x opamp to amplify the sounds of voice, door knocks, etc loud enough to be picked up by a microcontroller's Analog to Digital converter. Unit comes fully assembled as shown. Works from 2.7V up to 5.5V.
motion	changes in relative distance	PIR Motion Sensor Description: This is a simple to use motion sensor. Power it up and wait 1-2 seconds for the sensor to get a snapshot of the still room. If anything moves after that period, the 'alarm' pin will go low. Red wire is power (5 to 12V). Brown wire is GND. Black wire is open collector Alarm. This unit works great from 5 to 12V (datasheet shows 12V). You can also install a jumper wire past the 5V regulator on board to make this unit work at 3.3V. Sensor uses 1.6mA@3.3V. The alarm pin is an open collector meaning you will need a pull up resistor on the alarm pin. The open drain setup allows multiple motion sensors to be connected on a single input pin. If any of the motion sensors go off, the input pin will be pulled low. The connector is slightly odd but has a 0.1" pitch female connector making it compatible with jumper wires and 0.1" male headers.
photocell	light	Mini Photocell Description: This is a very small photocell. A photocell changes (also called a photodetector, CdS or photoconductive cell) resistance depending on the amount of light it is exposed to. These little sensors make great ambient light triggers (when light in the room turns on, do something). Features: Light resistance : ~1k Ohm Dark resistance : ~10k Ohm Max voltage : 150V Max power: 100mW
pressure	air or fluid pressure	Barometric Pressure Sensor - BMP085 Breakout Description: This is a simple breakout board for the BMP085 high-precision, low-power barometric pressure sensor. The BMP085 offers a measuring range of 300 to 1100 hPa with an absolute accuracy of down to 0.03 hPa. It's based on piezo-resistive technology for EMC robustness, high accuracy and linearity as well as long term stability. This sensor supports a voltage supply between 1.8 and 3.6VDC. It is designed to be connected directly to a micro-controller via the I²C bus This breadboard-friendly board breaks out all pins of the BMP085 to a 6-pin 0.1" pitch header. The analog and digital supplies (VDDD and VDDA) of the BMP085 are tied together and broken out to a single pin. We've also put two 4.7k pull-up resistors on the I2C lines. Features: Digital two wire (I2C) interface Wide barometric pressure range Flexible supply voltage range Ultra-low power consumption Low noise measurement Fully calibrated Temperature measurement included Ultra-flat, small footprint
potentiometer	rotation or linear position on an analog scale	Rotary Potentiometer - Linear Description: An adjustable potentiometer can open up many interesting user interfaces. Turn the pot and the resistance changes. Connect VCC to an outer pin, GND to the other, and the center pin will have a voltage that varies from 0 to VCC depending on the rotation of the pot. Hook the center pin to an ADC on a microcontroller and get a variable input from the user! This is a center-tap linear type potentiometer. The outer two pins will always show 10K resistance, the center pin resistance to one of the outer pins will vary from 10K Ohm to about 50 Ohm. The pot is linear meaning the resistance will vary linearly with its position. This is a good choice for general user interfaces. This pot works great in a breadboard but on a few breadboards, you may have to trim off the large metal anchors.
pulse	heartbeat rate	Polar Heart Rate Module - RMCM01 Description: This is a OEM module for the Polar Heart Rate system. This device works with any Polar heart rate strap to pickup the electromagnetic pulse and output a 1ms pulse indicating a heart beat has occurred. Embed a heart rate reading into your next project! The RMCM01 requires no antenna. It does require a 32kHz crystal but that crystal does not need capacitors. Please see the basic schematic below.
ranging	distance between objects	Ultrasonic Range Finder - Maxbotix LV-EZ1 Description: This is the fantastically easy to use sensor from Maxbotix. We are extremely pleased with the size, quality, and ease of use of this little range finder. The serial interface is a bit odd (it's RS232 instead of standard TTL), but the PWM and Analog interfaces will allow any micro to listen easily enough. The sensor provides very accurate readings of 0 to 255 inches (0 to 6.45m) in 1 inch increments with little or no dead zone! Maxbotix is offering the EZ0, EZ1, EZ2, EZ3, and EZ4 with progressively narrower beam angles allowing the sensor to match the application. Please see beam width explanation below. Control up to 10 sensors with only two pins! Checkout the Maxbotix FAQ listed below. Features: 42kHz Ultrasonic sensor Operates from 2.5-5.5V Low 2mA supply current 20Hz reading rate RS232 Serial Output - 9600bps Analog Output - 10mV/inch PWM Output - 147uS/inch Small, light weight module
rotary encoder	rotation on a digital scale	Description: This is a 12-step rotary encoder with a nice 'clicking' feel. It's breadboard friendly, and has a pretty handy select switch (by pushing in on the knob). The encoder is different from a potentiometer in that an encoder has full rotation without limits. The unit outputs gray code so that you can tell how much and in which direction the encoder has been turned.
stretch	physical deformation or strain	Description:The Stretch Sensor is a unique component that changes resistance when stretched. When relaxed the sensor material has a nominal resistance of 1000 ohms per linear inch. As the stretch sensor is stretched the resistance gradually increases. When the sensor is stretched 50 % its resistance will approximately double to 2.0 Kohms per inch.
smoke	airborne particles	Optical Dust Sensor - GP2Y1010AU0F Description: Sharp's GP2Y1010AU0F is an optical air quality sensor, designed to sense dust particles. An infrared emitting diode and a phototransistor are diagonally arranged into this device, to allow it to detect the reflected light of dust in air. It is especially effective in detecting very fine particles like cigarette smoke, and is commonly used in air purifier systems. The sensor has a very low current consumption (20mA max, 11mA typical), and can be powered with up to 7VDC. The output of the sensor is an analog voltage proportional to the measured dust density, with a sensitivity of 0.5V/0.1mg/m3. To interface with the sensor you need to connect to its 6-pin, 1.5mm pitch connector; we do have a mating connector for this.
switch	physical pressure on a digital scale	Concave Button - Red Description: This is a 35mm concave momentary push button similar to the ones you find on arcade games. Simple screw in design. Perfect for mashing. This button has a great tactile, 'clicky' feel. Features: Concave plunger design Durable nylon material Microswitch: max 3A @ 120 VAC Microswitch reliability tested to 10,000,000 cycles Includes 3 terminal microswitch Net weight: 25g
thermistor	temperature	Thermistor 10K Vishay part #: NTCLE100E3103JB0 Description: 10K thermistor with a negative temperature coefficient. Good choice for temp-sensing aplications.
tilt	angular attitude	Description:The "poor man's" accelerometer! Tilt sensors are switches that can detect basic motion/orientation. The metal tube has a little metal ball that rolls around in it, when its tilted upright, the ball rolls onto the contacts sticking out of end and shorts them together.

/ / navigation

/ / digital in-digital out

Adding the Microcontroller

LEDs

Connecting different colored LEDs

Flashing LED

IR LED

Piranha or High-Flux LED

Blinking an LED without delay

/ / Transistors

/ /Darlington Transistors and HIGH CURRENT DC DEVICES:

Parts

Prepare the breadboard

Program the microcontroller

Notes

/ / Multiple LEDs and Transistors

Digital In-Analog Out

Where can I find some PWM?

Exercise I—Analog Out

Low Pass Filter Circuit

//Analog in-digital out

//Piezoelectric Sensors

How it works

/ /Motor Pulse

/ /Getting Creative

// Analog in-Analog out

Making motions with servo motors

But doesn't Arduino have PWM?

Exercise

Servo Critters

//Voltage Dividers

Serial Communication-Arduino to Processing

Multiple Values

Call and Response

Sensors