Arduino experimenters guide hq

ARDX arduino experimentation kit Arduino Experimenter’s Guide (ARDX)

A Few Words ABOUT THIS KIT The overall goal of this kit is fun. Beyond this, the aim is to get you comfortable using a wide range of electronic components through small, simple and easy circuits. The focus is to get each circuit working then giving you the tools to figure out why. If you encounter any problems, want to ask a question, or would like to know more about any part, extra help is only an e-mail away help@oomlout.com. ABOUT .: OOMLOUT :. We’re a plucky little design company focusing on producing “delightfully fun open source products” To check out what we are up to http://www.oomlout.com ABOUT PROBLEMS We strive to deliver the highest level of quality in each and every thing we produce. If you ever find an ambiguous instruction, a missing piece, or would just like to ask a question, we’ll try our best to help out. help@oomlout.com (we like hearing about problems it helps us improve future versions) Thanks For Choosing .:oomlout:. All of .:oomlout:.'s projects are open source. What does this mean? It means everything involved in making this kit, be it this guide, 3D models, or code is available for free download. But it goes further, you're also free to reproduce and modify any of this material, then distribute it for yourself. The catch? Quite simple; it is released under a Creative Commons (By - Share Alike) license. This means you must credit .:oomlout:. in your design and share your developments in a similar manner. Why? We grew up learning and playing with open source software and the experience was good fun, we think it would be lovely if a similar experience was possible with physical things. More details on the Creative Commons CC (By - Share Alike) License can be found at http://ardx.org/CCLI ABOUT OPEN SOURCE HARDWARE

01 TBCN table of contents .: WHERE TO FIND EVERYTHING :. Before We Start {ASEM} Assembling the Pieces 02 {INST} Installing the Software 03 {PROG} A Small Programming Primer 04 {ELEC} A Small Electronics Primer 06 The Circuits {CIRC01} Getting Started - (Blinking LED) 08 {CIRC02} 8 LED Fun - (Multiple LEDs) 10 {CIRC03} Spin Motor Spin - (Transistor and Motor) 12 {CIRC04} A Single Servo - (Servos) 14 {CIRC05} 8 More LEDs - (74HC595 Shift Register) 16 {CIRC06} Music - (Piezo Elements) 18 {CIRC07} Button Pressing - (Pushbuttons) 20 {CIRC08} Twisting - (Potentiometers) 22 {CIRC09} Light - (Photo Resistors) 24 {CIRC10} Temperature - (TMP36 Temperature Sensor) 26 {CIRC11} Larger Loads - (Relays) 28

02 01 ASEM assembling the pieces Breadboard x1 Arduino x1 3mm x 10mm bolt x4 3mm nut x4 Arduino Holder x1 .: PUTTING IT TOGETHER :. .: For an introduction to what an Arduino is, visit :. .: http://ardx.org/INTR :.

03 02 INST installing (software and hardware) .: NOTE: :. .: Encountering problems? :. .: Would like more details? Using Linux? :. .: http://ardx.org/LINU :. Step 1: Download the software Goto http://arduino.cc/en/Main/Software And download the software for your operating system Windows XP Mac OSX Step 2: Unzip the Software Unzip arduino-00 -win.zip Recommended Path c:Program Files r r (r r - version #) Step 3: Shortcut Icon Open c:program filesarduino-00 Right Click Arduino.exe (send to>Desktop (create shortcut) ) r r r r - version #) ( Step 4: Plug In Your Arduino Plug your Arduino in: using the included USB cable, plug your Arduino board into a free USB port Wait for a box to pop up Step 5: Add new Hardware Skip searching the internet (click the next box when prompted to do so) Install from a Specific destination (click “Install from a list or specific location (Advanced)) Choose the Location c:program filesarduino-00r r driversFTDI USB Drivers Finished .: INSTALLING THE IDE :. This is the program used to write programs for the Arduino (meta?). It may seem a little daunting at first but once you have it installed and start playing around, its secrets will reveal themselves Step 5: Plug In Your Arduino Plug your Arduino in: using the included USB cable, plug your Arduino board into a free USB port Step 2: Open The .dmg Open (mount) arduino-00 -mac.dmg r r (r r - version #) Step 4: Install Drivers Goto "Arduino" device FTDI Drivers for Intel Macs ( _ _ ).pkg (FTDI Drivers for PPC Macs ( _ _ ).pkg Restart Double Click & Install r r r r r r r r Step 3: Copy The Application Goto "Arduino" (in the devices section of finder) Move "Arduino" Application to the "Applications" folder

// (single line comment) It is often useful to write notes to yourself as you go along about what each line of code does. To do this type two back slashes and everything until the end of the line will be ignored by your program. { } (curly brackets) Used to define when a block of code starts and ends (used in functions as well as loops) 04 03 PROG programming primer .: A Small Programming Primer:. The Arduino is programmed in the C language. This is a quick little primer targeted at people who have a little bit of programing experience and just need a briefing on the ideosyncrocies of C and the Arduino IDE. If you find the concepts a bit daunting, don't worry, you can start going through the circuits and pick up most of it along the way. For a more in depth intro the Arduino.cc website is a great resource ( ) http://www.ardx.org/ARDU STRUCTURE void setup(){ } All the code between the two curly brackets will be run once when your Arduino program first runs. Each Arduino program (often called a sketch) has two required functions (also called routines). void loop(){ } This function is run after setup has finished. After it has run once it will be run again, and again, until power is removed. SYNTAX ; (semicolon) Each line of code must be ended with a semicolon (a missing semicolon is often the reason for a programme refusing to compile) One of the slightly frustrating elements of C is its formating requirements (this also makes it very powerful). If you remember the following you should be alright. /* */(multi line comment) If you have a lot to say you can span several lines as a comment. Everything between these two symbols will be ignored in your program. A program is nothing more than instructions to move numbers around in an intelligent way. Variables are used to do the moving long (long) Used when an integer is not large enough. Takes 4 bytes (32 bits) of RAM and has a range between -2,147,483,648 and 2,147,483,648. int (integer) The main workhorse, stores a number in 2 bytes (16 bits). Has no decimal places and will store a value between -32,768 and 32,768. boolean (boolean) A simple True or False variable. Useful because it only uses one bit of RAM. char (character) Stores one character using the ASCII code (ie 'A' = 65). Uses one byte (8 bits) of RAM. The Arduino handles strings as an array of char’s float (float) Used for floating point math (decimals). Takes 4 bytes (32 bits) of RAM and has a range between -3.4028235E+38 and 3.4028235E+38. ARDUINO PROGRAMMING IN BRIEF VARIABLES

05 03 PROG programming primer MATHS OPERATORS = (assignment) makes something equal to something else (eg. x = 10 * 2 (x now equals 20)) % (modulo) gives the remainder when one number is divided by another (ex. 12 % 10 (gives 2)) + (addition) - (subtraction) * (multiplication) / (division) Operators used for manipulating numbers. (they work like simple maths) COMPARISON OPERATORS == (equal to) (eg. 12 == 10 is FALSE or 12 == 12 is TRUE) != (not equal to) (eg. 12 != 10 is TRUE or 12 != 12 is FALSE) < (less than) (eg. 12 < 10 is FALSE or 12 < 12 is FALSE or 12 < 14 is TRUE) > (greater than) (eg. 12 > 10 is TRUE or 12 > 12 is FALSE or 12 > 14 is FALSE) Operators used for logical comparison CONTROL STRUCTURE if(condition){ } else if( condition ){ } else { } This will execute the code between the curly brackets if the condition is true, and if not it will test the else if condition if that is also false the else code will execute. Programs are reliant on controlling what runs next, here are the basic control elements (there are many more online) for(int i = 0; i < #repeats; i++){ } Used when you would like to repeat a chunk of code a number of times (can count up i++ or down i-- or use any variable) DIGITAL digitalWrite(pin, value); Once a pin is set as an OUTPUT, it can be set either HIGH (pulled to +5 volts) or LOW (pulled to ground). pinMode(pin, mode); Used to set a pins mode, pin is the pin number you would like to address (0-19 (analog 0-5 are 14-19). the mode can either be INPUT or OUTPUT. int digitalRead(pin); Once a pin is set as an INPUT you can use this to return whether it is HIGH (pulled to +5 volts) or LOW (pulled to ground). ANALOG int analogWrite(pin, value); Some of the Arduino's pins support pulse width modulation (3, 5, 6, 9, 10, 11). This turns the pin on and off very quickly making it act like an analog output. The value is any number between 0 (0% duty cycle ~0v) and 255 (100% duty cycle ~5 volts). The Arduino is a digital machine but it has the ability to operate in the analog realm (through tricks). Here's how to deal with things that aren't digital. int analogRead(pin); When the analog input pins are set to input you can read their voltage. A value between 0 (for 0 volts) and 1024 (for 5 volts) will be returned .:For a full programming reference visit:. http://ardx.org/PROG

DC Motor What it Does: No. of Leads: Spins when a current is passed through it. 2 Identifying: Things to watch out for: This one is easy, it looks like a motor. - Using a transistor or relay that is rated Usually a cylinder with a shaft coming out for the size of motor you're using. of one end More Details on Wikipedia: http://ardx.org/MOTO Hobby Servo What it Does: No. of Leads: Takes a timed pulse and converts it into 3 an angular position of the output shaft. Things to watch out for: Identifying: - The plug is not polarized so make sure A plastic box with 3 wires coming out one it is plugged in the right way. side and a shaft with a plastic horn out More Details: the top. http://ardx.org/SERV 06 04 ELEC electronics primer .: A Small Electronics Primer:. ELECTRONICS IN BRIEF No previous electronic experience is required to have fun with this kit. Here are a few details about each component to make identifying, and perhaps understanding them, a bit easier. If at any point you are worried about how a component is used or why its not working the internet offers a treasure trove of advice, or we can be contacted at help@oomlout.com COMPONENT DETAILS LED (Light Emitting Diode) What it Does: No. of Leads: Emits light when a small current is 2 (one longer this one connects to positive) passed through it. (only in one direction) Things to watch out for: Identifying: - Will only work in one direction Looks like a mini light bulb. - Requires a current limiting resistor More Details on Wikipedia: http://ardx.org/LED Resistors What it Does: next page) Restricts the amount of current that can No. of Leads: flow through a circuit. 2 Identifying: Things to watch out for: Cylinder with wires extending from either - Easy to grab the wrong value (double check the colors before using) end. The resistance value is displayed More Details on Wikipedia: using a color coding system (for details see http://ardx.org/RESI Transistor What it Does: No. of Leads: Uses a small current to switch or amplify a 3 (Base, Collector, Emitter) much larger current. Things to watch out for: Identifying: - Plugging in the right way round.(also a current limiting resistor is often needed on the base pin) Comes in many different packages but you More Details on Wikipedia: can read the part number off the package. http://ardx.org/TRAN (P2N2222AG in this kit and find a datasheet online) Diode What it Does: No. of Leads: The electronic equivalent of a one way 2 valve. Allowing current to flow in one Things to watch out for: direction but not the other. - Will only work in one direction (current will flow if end with the line is connected to ground) Identifying: More Details on Wikipedia: Usually a cylinder with wires extending from http://ardx.org/DIOD either end. (and an off center line indicating polarity)

07 04 ELEC electronics primer Piezo Element What it Does: A pulse of current will cause it to click a No. of Leads: stream of pulses will cause it to emit a 2 tone. Things to watch out for: Identifying: - Difficult to misuse. In this kit it comes in a little black barrel, More Details: but sometimes they are just a gold disc. http://ardx.org/PIEZ Potentiometer What it Does: No. of Leads: Produces a variable resistance dependant 3 on the angular position of the shaft. Things to watch out for: Identifying: - Accidentally buying logarithmic scale. They can be packaged in many different More Details: form factors, look for a dial to identify. http://ardx.org/POTE IC (Integrated Circuit) What it Does: No. of Leads: Packages any range of complicated 2 - 100s (in this kit there is one with 3 (TMP36) and one with 16 (74HC595) electronics inside, an easy to use form factor Things to watch out for: Identifying: - Proper orientation.(look for marks showing pin 1) The part ID is written on the outside of the More Details: package. (this sometimes requires a lot of http://ardx.org/ICIC light or a magnifying glass to read) Photo Resistor What it Does: No. of Leads: Produces a variable resistance dependant 2 on the amount of incident light. Things to watch out for: Identifying: - Remember it needs to be in a voltage Usually a little disk with a clear top and a divider before it provides a useful input. curvy line underneath. More Details: http://ardx.org/PHOT Pushbutton What it Does: No. of Leads: Completes a circuit when it is pressed 4 Identifying: Things to watch out for: A little square with leads out the bottom - these are almost square so can be and a button on the top. inserted 90 degrees off angle. More Details: http://ardx.org/BUTT 0 - Black 5 - Green 20% - none 1 - Brown 6 - Blue 10% - silver 2 - Red 7 - Purple 5% - gold 3 - Orange 8 - Grey 4 - Yellow 9 - White first digit second digit # of zeros tolerance Examples: green-blue-brown - 560 ohms red-red-red - 2 200 ohms (2.2k) brown-black-orange - 10 000 ohms (10k) RESISTOR COLOR CODE LEAD CLIPPING Some components in this kit come with very long wire leads. To make them more compatible with a breadboard a couple of changes are required. LEDs: Clip the leads so the long lead is ~10mm (3/8”) long and the short one is ~7mm (9/32”) Resistors: Bend the leads down so they are 90 degrees to the cylinder. Then snip them so they are ~6mm (1/4”) long. Other Components: Other components may need clipping use your discretion when doing so. COMPONENT DETAILS (CONT.)

Arduino pin 13 LED (light emitting diode) resistor (560ohm) (green-blue-brown) gnd (ground) (-) 08 CIRC-01 WHAT WE’RE DOING: .:Getting Started:. .:(Blinking LED):. LEDs (light emitting diodes) are used in all sorts of clever things which is why we have included them in this kit. We will start off with something very simple, turning one on and off, repeatedly, producing a pleasant blinking effect. To get started grab the parts listed below, pin the layout sheet to your breadboard and then plug everything in. Once the circuit is assembled you'll need to upload the program. To do this plug the Arduino board into your USB port. Then select the proper port in Tools > Serial Port > (the comm port of your Arduino). Next upload the program by going to File > Upload to I/O Board (ctrl+U). Finally bask in the glory and possibility that controlling lights offers. If you are having trouble uploading, a full trouble shooting guide can be found here: http://ardx.org/TRBL Wire 10mm LED x1 560 Ohm Resistor Green-Blue-Brown x1 2 Pin Header x4 CIRC-01 Breadboard sheet x1 Parts: .:download:. breadboard layout sheet http://ardx.org/BBLS01 .:view:. assembling video http://ardx.org/VIDE01 The Internet longer lead + THE CIRCUIT: Schematic

NOT WORKING? (3 things to try) CODE (no need to type everything in just) 09 CIRC-01 File > Examples > Digital > Blink (example from the great arduino.cc site check it out for other ideas) /* Blink * Turns on an LED on for one second, then off for one second, * repeatedly. * Created 1 June 2005 By David Cuartielles * http://arduino.cc/en/Tutorial/Blink * based on an orginal by H. Barragan for the Wiring i/o board */ int ledPin = 13; // LED connected to digital pin 13 // The setup() method runs once, when the sketch starts void setup() { // initialize the digital pin as an output: pinMode(ledPin, OUTPUT); } // the loop() method runs over and over again, // as long as the Arduino has power void loop() { digitalWrite(ledPin, HIGH); // set the LED on delay(1000); // wait for a second digitalWrite(ledPin, LOW); // set the LED off delay(1000); // wait for a second }} More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC01 LED Not Lighting Up? LEDs will only work in one direction. Try taking it out and twisting it 180 degrees. (no need to worry, installing it backwards does no permanent harm) Changing the pin: Control the Brightness: The LED is connected to pin 13 but we can use any of Along with digital (on/off) control the Arduino can control the Arduino’s pins. To change it take the wire plugged some pins in an analog (brightness) fashion. (more details on into pin 13 and move it to a pin of your choice (from 0- this in later circuits). To play around with it. 13) (you can also use analog 0-5 analog 0 is 14...) Change the LED to pin 9: (also change the wire) ledPin = 13; -> int ledPin = 9; Then in the code change the line: int ledPin = 13; -> int ledPin = newpin; Replace the code inside the { }'s of loop() with this: Then upload the sketch: (ctrl-u) analogWrite(ledPin, new number); Change the Blink Time: (new number) = any number between 0 and 255. Unhappy with one second on one second off? 0 = off, 255 = on, in between = different brightness Fading: In the code change the lines: digitalWrite(ledPin, HIGH); We will use another included example program. To open go to. delay(time on); //(seconds * 1000) File > Examples > Analog > Fading digitalWrite(ledPin, LOW); delay(time off); //(seconds * 1000) Then upload to your board and watch as the LED fades in and then out. Still No Success? A broken circuit is no fun, send us an e-mail and we will get back to you as soon as we can. help@oomlout.com Program Not Uploading This happens sometimes, the most likely cause is a confused serial port, you can change this in tools>serial port> MAKING IT BETTER MORE, MORE, MORE:

Wire 10 CIRC-02 .:8 LED Fun:. .:Multiple LED’s:. We have caused one LED to blink, now its time to up the stakes. Lets connect eight. We'll also have an opportunity to stretch the Arduino a bit by creating various lighting sequences. This circuit is also a nice setup to experiment with writing your own programs and getting a feel for how the Arduino works. Along with controlling the LEDs we start looking into a few simple programming methods to keep your programs small. for() loops - used when you want to run a piece of code several times. arrays[] - used to make managing variables easier (its a group of variables) 5mm Green LED x8 560 Ohm Resistor Green-Blue-Brown x8 2 Pin Header x4 CIRC-02 Breadboard sheet x1 .:download:. breadboard layout sheet http://ardx.org/BBLS02 .:view:. assembling video http://ardx.org/VIDE02 LED resistor 560ohm gnd pin 3 pin 2 pin 4 pin 5 LED resistor 560ohm gnd pin 7 pin 6 pin 8 pin 9 WHAT WE’RE DOING: The Internet THE CIRCUIT: Schematic Parts:

NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE: Operating out of sequence With eight wires it's easy to cross a couple. Double check that the first LED is plugged into pin 2 and each pin there after. 11 CIRC-02 Download the Code from ( http://ardx.org/CODE02 ) (and then copy the text and paste it into an empty Arduino Sketch) More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC02 Some LEDs Fail to Light It is easy to insert an LED backwards. Check the LEDs that aren't working and ensure they the right way around. Switching to Loops: in the loop() function there are 4 lines. The last Extra Animations: Tired of this animation? Then try the other two three all start with a '//' this means the line is sample animations. Uncomment their lines and upload treated as a comment (not run). To switch the the program to your board and enjoy the new light program to use loops change the void loop() animations. (delete the slashes in front of row 3 and then 4) code to: //oneAfterAnotherNoLoop(); oneAfterAnotherLoop(); //oneOnAtATime(); Testing out your own Animations: Jump into the included code and start changing //inAndOut(); things. The main point is to turn an LED on use Upload the program, and notice that nothing has digitalWrite(pinNumber, HIGH); then to turn changed. You can take a look at the two it off use digitalWrite(pinNumber, LOW); . functions, each does the same thing, but use Type away, regardless of what you change you won't different approaches (hint the second one uses a break anything. for loop) Starting Afresh Its easy to accidentally misplace a wire without noticing. Pulling everything out and starting with a fresh slate is often easier than trying to track down the problem. //LED Pin Variables * will then turn them off int ledPins[] = {2,3,4,5,6,7,8,9}; //An array to hold the void oneAfterAnotherNoLoop(){ //pin each LED is connected to int delayTime = 100; //i.e. LED #0 is connected to pin 2 //the time (in milliseconds) to pause //between LEDs void setup() digitalWrite(ledPins[0], HIGH); //Turns on LED #0 { //(connected to pin 2) for(int i = 0; i < 8; i++){ delay(delayTime); //waits delayTime milliseconds //this is a loop and will repeat eight times ... pinMode(ledPins[i],OUTPUT); ... //we use this to set LED pins to output digitalWrite(ledPins[7], HIGH); //Turns on LED #7 } //(connected to pin 9) } delay(delayTime); //waits delayTime milliseconds //Turns Each LED Off void loop() // run over and over again digitalWrite(ledPins[7], LOW); //Turns off LED #7 { delay(delayTime); //waits delayTime milliseconds oneAfterAnotherNoLoop(); ... //this will turn on each LED one by //one then turn each oneoff -----more code in the downloadable version------ //oneAfterAnotherLoop(); //this does the same as onAfterAnotherNoLoop //but with much less typing //oneOnAtATime(); //inAndOut(); } /* * oneAfterAnotherNoLoop() - Will light one then * delay for delayTime then light the next LED it

12 CIRC-03 .:Spin Motor Spin:. .:Transistor & Motor:. The Arduino's pins are great for directly controlling small electric items like LEDs. However, when dealing with larger items (like a toy motor or washing machine), an external transistor is required. A transistor is incredibly useful. It switches a lot of current using a much smaller current. A transistor has 3 pins. For a negative type (NPN) transistor you connect your load to collector and the emitter to ground. Then when a small current flows from base to the emitter a current will flow through the transistor and your motor will spin (this happens when we set our Arduino pin HIGH). There are literally thousands of different types of transistors, allowing every situation to be perfectly matched. We have chosen a P2N2222AG a rather common general purpose transistor. The important factors in our case are that its maximum voltage (40 v) and its maximum current (600 milliamp) are both high enough for our toy motor (full details can be found on its datasheet http://ardx.org/2222 ) (The 1N4001 diode is acting as a flyback diode for details on why its there visit: http://ardx.org/4001) Wire Transistor P2N2222AG (TO92) x1 2.2k Ohm Resistor Red-Red-Red x1 2 Pin Header x4 CIRC-03 Breadboard sheet x1 Toy Motor x1 Arduino pin 9 resistor (2.2kohm) gnd (ground) (-) Collector Emitter Base Motor +5 volts Transistor P2N2222AG the transistor will have P2N2222AG printed on it (some variations will have different pin assignments!) Diode (1N4001) x1 Diode .:download:. breadboard layout sheet http://ardx.org/BBLS03 .:view:. assembling video http://ardx.org/VIDE03 .:NOTE: if your arduino is resetting you need to install the optional capacitor:. WHAT WE’RE DOING: THE CIRCUIT: Schematic Parts: The Internet

Still No Luck? if you sourced your own motor, double check that it will work with 5 volts and that it does not draw too much power. 13 CIRC-03 More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC03 Motor Not Spinning? if you sourced your own transistor, double check with the data sheet that the pinout is compatible with a P2N2222A (many are reversed) Controlling Speed: In the loop() section change it to this // motorOnThenOff(); We played with the Arduino's ability to control the motorOnThenOffWithSpeed(); brightness of an LED earlier now we will use the same //motorAcceleration(); Then upload the programme. You can change the speeds by feature to control the speed of our motor. The Arduino changing the variables onSpeed and offSpeed does this using something called Pulse Width Modulation (PWM). This relies on the Arduino's ability to Accelerating and decelerating: operate really really fast. Rather than directly controlling Why stop at two speeds, why not accelerate and decelerate the voltage coming from the pin the Arduino will switch the motor. To do this simply change the loop() code to read the pin on and off very quickly. In the computer world // motorOnThenOff(); // motorOnThenOffWithSpeed(); this is going from 0 to 5 volts many times a second, but motorAcceleration(); in the human world we see it as a voltage. For example Then upload the program and watch as your motor slowly if the Arduino is PWM'ing at 50% we see the light accelerates up to full speed then slows down again. If you dimmed 50% because our eyes are not quick enough to would like to change the speed of acceleration change the see it flashing on and off. The same feature works with variable delayTime (larger means a longer acceleration time) transistors. Don't believe me? Try it out. Still Not Working? Sometimes the Arduino board will disconnect from the computer. Try un-plugging and then re-plugging it into your USB port. Download the Code from ( http://ardx.org/CODE03 ) (then simply copy the text and paste it into an empty Arduino Sketch) int motorPin = 9; //pin the motor is connected to void setup() //runs once void motorOnThenOffWithSpeed(){ { int onSpeed = 200;// a number between pinMode(motorPin, OUTPUT); //0 (stopped) and 255 (full speed) } int onTime = 2500; int offSpeed = 50;// a number between void loop() // run over and over again //0 (stopped) and 255 (full speed) { int offTime = 1000; motorOnThenOff(); analogWrite(motorPin, onSpeed); //motorOnThenOffWithSpeed(); // turns the motor On //motorAcceleration(); delay(onTime); // waits for onTime milliseconds } analogWrite(motorPin, offSpeed); // turns the motor Off /* delay(offTime); // waits for offTime milliseconds * motorOnThenOff() - turns motor on then off } * (notice this code is identical to the code we void motorAcceleration(){ used for int delayTime = 50; //time between each speed step * the blinking LED) for(int i = 0; i < 256; i++){ */ //goes through each speed from 0 to 255 void motorOnThenOff(){ analogWrite(motorPin, i); //sets the new speed int onTime = 2500; //on time delay(delayTime);// waits for delayTime milliseconds int offTime = 1000; //off time } digitalWrite(motorPin, HIGH); for(int i = 255; i >= 0; i--){ // turns the motor On //goes through each speed from 255 to 0 delay(onTime); // waits for onTime milliseconds analogWrite(motorPin, i); //sets the new speed digitalWrite(motorPin, LOW); delay(delayTime);//waits for delayTime milliseconds // turns the motor Off } delay(offTime);// waits for offTime milliseconds } } NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE:

WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic 14 CIRC-04 .:A Single Servo:. .:Servos:. Spinning a motor is good fun but when it comes to projects where motion control is required they tend to leave us wanting more. The answer? Hobby servos. They are mass produced, widely available and cost anything from a couple of dollars to hundreds. Inside is a small gearbox (to make the movement more powerful) and some electronics (to make it easier to control). A standard servo is positionable from 0 to 180 degrees. Positioning is controlled through a timed pulse, between 1.25 milliseconds (0 degrees) and 1.75 milliseconds (180 degrees) (1.5 milliseconds for 90 degrees). Timing varies between manufacturer. If the pulse is sent every 25-50 milliseconds the servo will run smoothly. One of the great features of the Arduino is it has a software library that allows you to control two servos (connected to pin 9 or 10) using a single line of code. Wire 3 Pin Header x1 Mini Servo x1 2 Pin Header x4 CIRC-04 Breadboard sheet x1 Arduino pin 9 gnd (ground) (-) gnd (black/ brown) signal (orange) +5v (red) Mini Servo +5 volts (5V) .:download:. breadboard layout sheet http://ardx.org/BBLS04 .:view:. assembling video http://ardx.org/VIDE04

Still not Working A mistake we made a time or two was simply forgetting to connect the power (red and brown wires) to +5 volts and ground. 15 CIRC-04 File > Examples > Library-Servo > Sweep (example from the great arduino.cc site check it out for other great ideas) More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC04 Servo Not Twisting? Even with colored wires it is still shockingly easy to plug a servo in backwards. This might be the case. Potentiometer Control: void loop() { We have yet to experiment with inputs but if you would like int pulseTime = 2100; //(the number of microseconds //to pause for (1500 90 degrees to read ahead, there is an example program File > Library- // 900 0 degrees 2100 180 degrees) digitalWrite(servoPin, HIGH); Servo > Knob. This uses a potentiometer (CIRC08) to delayMicroseconds(pulseTime); digitalWrite(servoPin, LOW); control the servo. You can find instructions online here: delay(25); http://ardx.org/KNOB } Great Ideas: Self Timing: Servos can be used to do all sorts of great things, here are a few of While it is easy to control a servo using the Arduino's included our favorites. library sometimes it is fun to figure out how to program something yourself. Try it. We're controlling the pulse directly Xmas Hit Counter so you could use this method to control servos on any of the http://ardx.org/XMAS Arduino's 20 available pins (you need to highly optimize this code before doing that). Open Source Robotic Arm (uses a servo controller as well as the Arduino) http://ardx.org/RARM int servoPin = 9; void setup(){ Servo Walker pinMode(servoPin,OUTPUT); http://ardx.org/SEWA } // Sweep // by BARRAGAN <http://barraganstudio.com> #include <Servo.h> Servo myservo; // create servo object to control a servo int pos = 0; // variable to store the servo position void setup() { myservo.attach(9); // attaches the servo on pin 9 to the servo object } void loop() { for(pos = 0; pos < 180; pos += 1) // goes from 0 degrees to 180 degrees { // in steps of 1 degree myservo.write(pos); // tell servo to go to position in variable 'pos' delay(15); // waits 15ms for the servo to reach the position } for(pos = 180; pos>=1; pos-=1) // goes from 180 degrees to 0 degrees { myservo.write(pos); // tell servo to go to position in variable 'pos' delay(15); // waits 15ms for the servo to reach the position } } Fits and Starts If the servo begins moving then twitches, and there's a flashing light on your Arduino board, the power supply you are using is not quite up to the challenge. Using a fresh battery instead of USB should solve this problem. NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE:

WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic 16 CIRC-05 .:8 More LEDs:. .:74HC595 Shift Register:. Time to start playing with chips. Or integrated circuits (ICs) as they like to be called. The external packaging of a chip can be very deceptive for example the chip on the Arduino board (a micro controller) and the one we will use in this circuit (a shift register) look very similar but are in fact rather different, for example the price of the Atmega chip on the arduino board is a few dollars while the 74hc595 is a couple dozen cents. It's a good introductory chip, and once your comfortable playing around with it and its datasheet (available online http://ardx.org/74HC595 ) the world of chips will be your oyster. The shift register (also called a serial to parallel converter), will give you an additional 8 outputs (to control LEDs and the like) using only three arduino pins. They can also be linked together to give you a nearly unlimited number of outputs using the same four pins. To use it you “clock in” the data and then latch lock it in (latch it). To do this you set the data pin to either HIGH or LOW, pulse the clock, then set the data pin again and pulse the clock repeating until you have shifted out 8 bits of data. Then you pulse the latch and the 8 bits are transferred to the shift registers pins. It sounds complicated but is really simple once you get the hang of it. (for a more in depth look at how a shift register works visit: http://ardx.org/SHIF) Wire Shift Register 74HC595 x1 560 Ohm Resistor Green-Blue-Brown x8 2 Pin Header x4 CIRC-05 Breadboard sheet x1 Red LED x8 LED resistor (560ohm) gnd (ground) (-) pin 4 pin 3 pin 2 0 1 2 3 4 5 6 7 data clock latch +5V gnd 74HC595 +5 volts There is a half moon cutout, this goes at the top .:download:. breadboard layout sheet http://ardx.org/BBLS05 .:view:. assembling video http://ardx.org/VIDE05

Not Quite Working Sorry to sound like a broken record but it is probably something as simple as a crossed wire. 17 CIRC-05 More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC05 The Arduino’s Power LED goes out This happened to us a couple of times, it happens when the chip is inserted backwards. If you fix it quickly nothing will break. //between LED updates Doing it the hard way: for(int i = 0; i < 8; i++){ An Arduino makes rather complex actions very easy, shifting out data is changeLED(i,ON); one of these cases. However one of the nice features of an Arduino is delay(delayTime); } you can make things as easy or difficult as you like. Lets try an for(int i = 0; i < 8; i++){ example of this. In your loop switch the line. changeLED(i,OFF); updateLEDs(i) -> updateLEDsLong(i); delay(delayTime); } Upload the program and notice nothing has changed. If you look at the code you can see how we are communicating with the chip one bit at a And upload this will cause the lights to light up one after another and then off time. (for more details http://ardx.org/SPI ) in a similar manner. Check the code and wikipedia to see how it works, or shoot us an e-mail if you have questions. Controlling Individual LEDs: Time to start controlling the LEDs in a similar method as we did in More Animations: CIRC02. As the eight LED states are stored in one byte (an 8 bit value) Now things get more interesting. If you look back to the code from CIRC02 (8 for details on how this works try http://ardx.org/BINA. An Arduino is LED Fun) you see we change the LEDs using digitalWrite(led, state), this is very good at manipulating bits and there are an entire set of operators the same format as the routine we wrote changeLED(led, state). You can use that help us out. Details on bitwise maths ( http://ardx.org/BITW ) the animations you wrote for CIRC02 by copying the code into this sketch and changing all the digitalWrite()'s to changeLED()'s. Powerful? Very. (you'll also Our implementation. Replace the loop() code with need to change a few other things but follow the compile errors and it works int delayTime = 100; //the number of milliseconds itself out) to delay Frustration? Shoot us an e-mail, this circuit is both simple and complex at the same time. We want to hear about problems you have so we can address them in future editions. help@oomlout.com Download the Code from ( http://ardx.org/CODE05 ) (copy the text and paste it into an empty Arduino Sketch) //Pin Definitions //The 74HC595 uses a protocol called SPI //Which has three pins int data = 2; digitalWrite(latch, LOW); int clock = 3; int latch = 4; //Pulls the chips latch low shiftOut(data, clock, MSBFIRST, value); void setup() //runs once //Shifts out 8 bits to the shift register { pinMode(data, OUTPUT); pinMode(clock, OUTPUT); digitalWrite(latch, HIGH); pinMode(latch, OUTPUT); } //Pulls the latch high displaying the data } void loop() // run over and over again { ---------- More Code Online ---------- int delayTime = 100; //delay between LED updates for(int i = 0; i < 256; i++){ updateLEDs(i); delay(delayTime); } } /* * updateLEDs() - sends the LED states set * in value to the 74HC595 sequence */ void updateLEDs(int value){ NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE:

WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic Arduino pin 9 gnd (ground) (-) Piezo Element 18 CIRC-06 .:Music:. .:Piezo Elements:. To this point we have controlled light, motion, and electrons, Lets tackle sound next. But sound is an analog phenomena, how will our digital Arduino cope? We will once again rely on its incredible speed which will let it mimic analog behavior. To do this, we will attach a piezo element to one of the Arduino's digital pins. A piezo element makes a clicking sound each time it is pulsed with current. If we pulse it at the right frequency (for example 440 times a second to make the note middle A) these clicks will run together to produce notes. Lets get to experimenting with it and get your Arduino playing 'Twinkle Twinkle Little Star'. Wire Piezo Element x1 2 Pin Header x4 CIRC-06 Breadboard sheet x1 .:download:. breadboard layout sheet http://ardx.org/BBLS06 .:view:. assembling video http://ardx.org/VIDE06

NOT WORKING? (3 things to try) MAKING IT BETTER MORE, MORE, MORE: 19 CIRC-06 Can't Think While the Melody is Playing. Just pull up the piezo element whilst you think, upload your program then plug it back in. More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC06 No Sound Given the size and shape of the piezo element it is easy to miss the right holes on the breadboard. Try double checking its placement. char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', Playing with the speed: 'C' }; The timing for each note is calculated based on int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, variables, as such we can tweak the sound of each note 1014, 956 }; or the timing. To change the speed of the melody you Composing your own melodies: The program is pre-set to play 'Twinkle Twinkle Little Star' need to change only one line. int tempo = 300; ---> int tempo = (new #) however the way it is programmed makes changing the song Change it to a larger number to slow the melody down, easy. Each song is defined in one int and two arrays, the int or a smaller number to speed it up. length defines the number of notes, the first array Tuning the notes: notes[] defines each note, and the second beats[] If you are worried about the notes being a little out of defines how long each note is played. Some Examples: tune this can be fixed as well. The notes have been Twinkle Twinkle Little Star calculated based on a formula in the comment block at int length = 15; char notes[] = "ccggaagffeeddc "; the top of the program. But to tune individual notes just int beats[] = { 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, adjust their values in the tones[] array up or down 1, 1, 2, 4 }; Happy Birthday (first line) until they sound right. (each note is matched by its int length = 13; name in the names[] (array ie. c = 1915 ) char notes[] = "ccdcfeccdcgf "; int beats[] = {1,1,1,1,1,2,1,1,1,1,1,2,4}; Tired of Twinkle Twinkle Little Star? The code is written so you can easily add your own songs, check out the code below to get started. /* Melody * (cleft) 2005 D. Cuartielles for K3 * * This example uses a piezo speaker to play melodies. It sends digitalWrite(speakerPin, LOW); * a square wave of the appropriate frequency to the piezo, delayMicroseconds(tone); * generating the corresponding tone. } * } * The calculation of the tones is made following the * mathematical operation: void playNote(char note, int duration) { * char names[] = { 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'C' }; * timeHigh = period / 2 = 1 / (2 * toneFrequency) int tones[] = { 1915, 1700, 1519, 1432, 1275, 1136, 1014, 956 * }; * where the different tones are described as in the table: // play the tone corresponding to the note name * for (int i = 0; i < 8; i++) { * note frequency period timeHigh if (names[i] == note) { * c 261 Hz 3830 1915 playTone(tones[i], duration); * d 294 Hz 3400 1700 } * e 329 Hz 3038 1519 } * f 349 Hz 2864 1432 } * g 392 Hz 2550 1275 * a 440 Hz 2272 1136 void setup() { * b 493 Hz 2028 1014 pinMode(speakerPin, OUTPUT); * C 523 Hz 1912 956 } * * http://www.arduino.cc/en/Tutorial/Melody void loop() { */ for (int i = 0; i < length; i++) { if (notes[i] == ' ') { int speakerPin = 9; delay(beats[i] * tempo); // rest } else { int length = 15; // the number of notes playNote(notes[i], beats[i] * tempo); char notes[] = "ccggaagffeeddc "; // a space represents a rest } int beats[] = { 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 4 }; // pause between notes int tempo = 300; delay(tempo / 2); } } void playTone(int tone, int duration) { for (long i = 0; i < duration * 1000L; i += tone * 2) { digitalWrite(speakerPin, HIGH); delayMicroseconds(tone); File > Examples > Digital > Melody (example from the great arduino.cc site check it out for other great ideas) CODE (no need to type everything in just)

WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic 20 CIRC-07 .:Button Pressing:. .:Pushbuttons:. Up to this point we have focused entirely on outputs, time to get our Arduino to listen, watch and feel. We'll start with a simple pushbutton. Wiring up the pushbutton is simple. There is one component, the pull up resistor, that might seem out of place. This is included because an Arduino doesn't sense the same way we do (ie button pressed, button unpressed). Instead it looks at the voltage on the pin and decides whether it is HIGH or LOW. The button is set up to pull the Arduino's pin LOW when it is pressed, however, when the button is unpressed the voltage of the pin will float (causing occasional errors). To get the Arduino to reliably read the pin as HIGH when the button is unpressed, we add the pull up resistor. (note: the first example program uses only one of the two buttons) Wire Pushbutton x2 560 Ohm Resistor Green-Blue-Brown x1 2 Pin Header x4 CIRC-07 Breadboard sheet x1 Red LED x1 10k Ohm Resistor Brown-Black-Orange x2 Arduino pin 13 LED resistor (560ohm) gnd (ground) (-) pin 2 pushbutton pin 3 +5 volts Arduino resistor (10k ohm) .:download:. breadboard layout sheet http://ardx.org/BBLS07 .:view:. assembling video http://ardx.org/VIDE07

NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE: Light Not Fading A bit of a silly mistake we constantly made, when you switch from simple on off to fading remember to move the LED wire from pin 13 to pin 9 21 CIRC-07 File > Examples > Digital > Button (example from the great arduino.cc site check it out for other great ideas) /* * Button * by DojoDave <http://www.0j0.org> * * Turns on and off a light emitting diode(LED) connected to digital * pin 13, when pressing a pushbutton attached to pin 7. * http://www.arduino.cc/en/Tutorial/Button */ int ledPin = 13; // choose the pin for the LED int inputPin = 2; // choose the input pin (for a pushbutton) int val = 0; // variable for reading the pin status void setup() { pinMode(ledPin, OUTPUT); // declare LED as output pinMode(inputPin, INPUT); // declare pushbutton as input } void loop(){ val = digitalRead(inputPin); // read input value if (val == HIGH) { // check if the input is HIGH digitalWrite(ledPin, LOW); // turn LED OFF } else { digitalWrite(ledPin, HIGH); // turn LED ON } } More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC07 Light Not Turning On The pushbutton is square and because of this it is easy to put it in the wrong way. Give it a 90 degree twist and see if it starts working. On button off button: Fading up and down: The initial example may be a little underwhelming (ie. I Lets use the buttons to control an analog signal. To do this don't really need an Arduino to do this), lets make it a you will need to change the wire connecting the LED from pin little more complicated. One button will turn the LED on 13 to pin 9, also change this in code. int ledPin = 13; ----> int ledPin = 9; the other will turn the LED off. Change the code to. Next change the loop() code to read. int ledPin = 13; // choose the pin for the LED int inputPin1 = 3; // button 1 int value = 0; int inputPin2 = 2; // button 2 void loop(){ if (digitalRead(inputPin1) == LOW) { value--; } void setup() { else if (digitalRead(inputPin2) == LOW) { value++; } pinMode(ledPin, OUTPUT); // declare LED as output value = constrain(value, 0, 255); pinMode(inputPin1, INPUT); // make button 1 an input analogWrite(ledPin, value); pinMode(inputPin2, INPUT); // make button 2 an input delay(10); } } void loop(){ Changing Fade Speed: if (digitalRead(inputPin1) == LOW) { digitalWrite(ledPin, LOW); // turn LED OFF If you would like the LED to fade faster or slower, there is only } else if (digitalRead(inputPin2) == LOW) { digitalWrite(ledPin, HIGH); // turn LED ON one line of code that needs changing; } delay(10); ----> delay(new #); } To fade faster make the number smaller, slower requires a Upload the program to your board, and start toggling the larger number. LED on and off. Underwhelmed? No worries these circuits are all super stripped down to make playing with the components easy, but once you throw them together the sky is the limit.

WHAT WE’RE DOING: The Internet THE CIRCUIT: Schematic .:Twisting:. .:Potentiometers:. Along with the digital pins the Arduino has it also has 6 pins which can be used for analog input. These inputs take a voltage (from 0 to 5 volts) and convert it to a digital number between 0 (0 volts) and 1024 (5 volts) (10 bits of resolution). A very useful device that exploits these inputs is a potentiometer (also called a variable resistor). When it is connected with 5 volts across its outer pins the middle pin will read some value between 0 and 5 volts dependent on the angle to which it is turned (ie. 2.5 volts in the middle). We can then use the returned values as a variable in our program. Wire Potentiometer 10k ohm x1 560 Ohm Resistor Green-Blue-Brown x1 2 Pin Header x4 CIRC-08 Breadboard sheet x1 Green LED x1 Arduino pin 13 LED (light emitting diode) resistor (560ohm) (blue-green-brown) gnd (ground) (-) Potentiometer +5 volts Arduino analog pin 2 .:download:. breadboard layout sheet http://ardx.org/BBLS08 .:view:. assembling video http://ardx.org/VIDE08 22 CIRC-08 Parts:

Not Working Make sure you haven't accidentally connected the potentiometer's wiper to digital pin 2 rather than analog pin 2. (the row of pins beneath the power pins) File > Examples > Analog > AnalogInput (example from the great arduino.cc site check it out for other great ideas) /* Analog Input * Demonstrates analog input by reading an analog sensor on analog * pin 0 and turning on and off a light emitting diode(LED) connected to digital pin 13. * The amount of time the LED will be on and off depends on the value obtained by * analogRead(). * Created by David Cuartielles * Modified 16 Jun 2009 * By Tom Igoe * http://arduino.cc/en/Tutorial/AnalogInput */ int sensorPin = 0; // select the input pin for the potentiometer int ledPin = 13; // select the pin for the LED int sensorValue = 0; // variable to store the value coming from the sensor void setup() { pinMode(ledPin, OUTPUT); //declare the ledPin as an OUTPUT: } void loop() { sensorValue = analogRead(sensorPin);// read the value from the sensor: digitalWrite(ledPin, HIGH); // turn the ledPin on delay(sensorValue); // stop the program for <sensorValue> milliseconds: digitalWrite(ledPin, LOW); // turn the ledPin off: delay(sensorValue); // stop the program for for <sensorValue> milliseconds: } More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC08 Sporadically Working This is most likely due to a slightly dodgy connection with the potentiometer's pins. This can usually be conquered by taping the potentiometer down. Threshold Switching: Then change the loop code to. void loop() { Sometimes you will want to switch an output when a value int value = analogRead(potPin) / 4; analogWrite(ledPin, value); exceeds a certain threshold. To do this with a } potentiometer change the loop() code to. Upload the code and watch as your LED fades in relation to void loop() { your potentiometer spinning. (Note: the reason we divide the int threshold = 512; if(analogRead(potPin) > threshold){ value by 4 is the analogRead() function returns a value from 0 digitalWrite(ledPin, HIGH);} to 1024 (10 bits), and analogWrite() takes a value from 0 to else{ digitalWrite(ledPin, LOW);} } 255 (8 bits) ) This will cause the LED to turn on when the value is above Controlling a Servo: 512 (about halfway), you can adjust the sensitivity by This is a really neat example and brings a couple of circuits changing the threshold value. together. Wire up the servo like you did in CIRC-04, then open Fading: the example program Knob (File > Examples > Library- Lets control the brightness of an LED directly from the Servo > Knob ), then change one line of code. potentiometer. To do this we need to first change the pin int potpin = 0; ----> int potpin = 2; the LED is connected to. Move the wire from pin 13 to pin Upload to your Arduino and then watch as the servo shaft turns 9 and change one line in the code. as you turn the potentiometer. int ledPin = 13; ----> int ledPin = 9; Still Backward You can try operating the circuit upside down. Sometimes this helps. 23 CIRC-08 NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE:

24 CIRC-09 .:Light:. .:Photo Resistors:. Whilst getting input from a potentiometer can be useful for human controlled experiments, what do we use when we want an environmentally controlled experiment? We use exactly the same principles but instead of a potentiometer (twist based resistance) we use a photo resistor (light based resistance). The Arduino cannot directly sense resistance (it senses voltage) so we set up a voltage divider (http://ardx.org/VODI). The exact voltage at the sensing pin is calculable, but for our purposes (just sensing relative light) we can experiment with the values and see what works for us. A low value will occur when the sensor is well lit while a high value will occur when it is in darkness. Wire Photo-Resistor x1 560 Ohm Resistor Green-Blue-Brown x1 2 Pin Header x4 CIRC-09 Breadboard sheet x1 Green LED x1 10k Ohm Resistor Brown-Black-Orange x1 Arduino pin 13 LED resistor (560ohm) gnd (ground) (-) +5 volts photo resistor resistor (10k ohm) Arduino analog pin 0 .:download:. breadboard layout sheet http://ardx.org/BBLS09 .:view:. assembling video http://ardx.org/VIDE09 WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic

NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE: Still not quite working? You may be in a room which is either too bright or dark. Try turning the lights on or off to see if this helps. Or if you have a flashlight near by give that a try. It Isn't Responding to Changes in Light. Given that the spacing of the wires on the photo-resistor is not standad, it is easy to misplace it. Double check its in the right place More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC09 LED is Remaining Dark This is a mistake we continue to make time and time again, if only they could make an LED that worked both ways. Pull it up and give it a twist. Reverse the response: Light controlled servo: Perhaps you would like the opposite response. Don't Lets use our newly found light sensing skills to control a servo worry we can easily reverse this response just change. (and at the same time engage in a little bit of Arduino code analogWrite(ledPin, lightLevel); ----> hacking). Wire up a servo connected to pin 9 (like in CIRC- analogWrite(ledPin, 255 - lightLevel); 04). Then open the Knob example program (the same one we Upload and watch the response change. used in CIRC-08) File > Examples > Library-Servo > Knob. Upload the code to your board and watch as it works Night light: Rather than controlling the brightness of the LED in unmodified. Using the full range of your servo: response to light, lets instead turn it on or off based on You'll notice that the servo will only operate over a limited a threshold value. Change the loop() code with. void loop(){ portion of its range. This is because with the voltage dividing int threshold = 300; circuit we use the voltage on analog pin 0 will not range from if(analogRead(lightPin) > threshold){ digitalWrite(ledPin, HIGH); 0 to 5 volts but instead between two lesser values (these }else{ digitalWrite(ledPin, LOW); values will change based on your setup). To fix this play with } the val = map(val, 0, 1023, 0, 179); line. For hints on what to } do visit http://arduino.cc/en/Reference/Map . Download the Code from ( http://ardx.org/CODE09 ) (copy the text and paste it into an empty Arduino Sketch) /* * A simple programme that will change the //output * intensity of an LED based on the amount of } * light incident on the photo resistor. /* * * loop() - this function will start after setup */ * finishes and then repeat */ //PhotoResistor Pin void loop() int lightPin = 0; //the analog pin the { //photoresistor is int lightLevel = analogRead(lightPin); //Read the //connected to // lightlevel //the photoresistor is not lightLevel = map(lightLevel, 0, 900, 0, 255); //calibrated to any units so //adjust the value 0 to 900 to //this is simply a raw sensor lightLevel = constrain(lightLevel, 0, 255); value (relative light) //make sure the value is betwween 0 and 255 //LED Pin analogWrite(ledPin, lightLevel); //write the value int ledPin = 9;//the pin the LED is connected to } //we are controlling brightness so //we use one of the PWM (pulse //width modulation pins) void setup() { pinMode(ledPin, OUTPUT); //sets the led pin to 25 CIRC-09

26 CIRC-10 .:Temperature:. .:TMP36 Precision Temperature Sensor:. What's the next phenomena we will measure with our Arduino? Temperature. To do this we'll use a rather complicated IC (integrated circuit) hidden in a package identical to our P2N2222AG transistors. It has three pins ground, signal and +5 volts, and is easy to use. It outputs 10 millivolts per degree centigrade on the signal pin (to allow measuring temperatures below freezing there is a 500 mV offset eg. 25 C = 750 mV, 0 ). To convert this from the digital value to degrees we will use some of the Arduino's maths abilities. Then to display it we'll use one of the IDE's rather powerful features, the debug window. We'll output the value over a serial connection to display on the screen. Let's get to it. One extra note, this circuit uses the Arduino IDE's serial monitor. To open this, first upload the program then click the button which looks like a square with an antennae. The TMP36 Ddatasheet: http://ardx.org/TMP36 ° ° C = 500mV Wire TMP36 Temperature Sensor x1 2 Pin Header x4 CIRC-10 Breadboard sheet x1 +5 volts TMP36 (precision temperature sensor) gnd (ground) (-) Arduino analog pin 0 gnd +5v signal the chip will have TMP36 printed on it .:download:. breadboard layout sheet http://ardx.org/BBLS10 .:view:. assembling video http://ardx.org/VIDE10 WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic

Gibberish is Displayed This happens because the serial monitor is receiving data at a different speed than expected. To fix this, click the pull-down box that reads "*** baud" and change it to "9600 baud". 27 CIRC-10 More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC10 Nothing Seems to Happen This program has no outward indication it is working. To see the results you must open the Arduino IDE's serial monitor. (instructions on previous page) Outputting voltage: do this first revert to the original code then change: Serial.println(temperature); This is a simple matter of changing one line. Our ----> Serial.print(temperature); sensor outputs 10mv per degree centigrade so to get Serial.println(" degrees centigrade"); voltage we simply display the result of getVoltage(). The change to the first line means when we next output it delete the line temperature = (temperature - .5) * 100; will appear on the same line, then we add the informative Outputting degrees Fahrenheit: text and a new line. Again this is a simple change requiring only math. to go Changing the serial speed: If you ever wish to output a lot of data over the serial line degrees C ----> degrees F we use the formula. ( F = C * 1.8) + 32 ) time is of the essence. We are currently transmitting at 9600 add the line baud but much faster speeds are possible. To change this temperature = (((temperature - .5) * 100)*1.8) + 32; change the line: Serial.begin(9600); ----> Serial.begin(115200); before Serial.println(temperature); Upload the sketch turn on the serial monitor, then change More informative output: the speed from 9600 baud to 115200 baud in the pull down Lets add a message to the serial output to make what menu. You are now transmitting data 12 times faster. is appearing in the Serial Monitor more informative. To Temperature Value is Unchanging. Try pinching the sensor with your fingers to heat it up or pressing a bag of ice against it to cool it down. Download the Code from ( http://ardx.org/CODE10) (copy the text and paste it into an empty Arduino Sketch) /* --------------------------------------------- void loop() * | Arduino Experimentation Kit Example Code | // run over and over again * | CIRC-10 .: Temperature :. | { * --------------------------------------------- float temperature = getVoltage(temperaturePin); * //getting the voltage reading from the * A simple program to output the current temperature //temperature sensor * to the IDE's debug window * For more details on this circuit: temperature = (temperature - .5) * 100;//converting from 10 //TMP36 Pin Variables mv int temperaturePin = 0;//the analog pin the TMP36's //per degree wit 500 mV offset to //Vout pin is connected to //degrees ((volatge - 500mV) times //the resolution is 100) //10 mV / degree centigrade Serial.println(temperature); //printing the result //(500 mV offset) to make delay(1000); //waiting a second //negative temperatures an } option /* void setup() * getVoltage() - returns the voltage on the analog input { * defined by pin Serial.begin(9600); //Start the serial connection */ //with the computer float getVoltage(int pin){ //to view the result open the return (analogRead(pin) * .004882814);//converting from a 0 //serial monitor //to 1024 digital range //last button beneath the file // to 0 to 5 volts //bar (looks like a box with an //(each 1 reading equals ~ 5 //antenna) millivolts } } NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE:

28 CIRC-11 .:Larger Loads:. .:Relays:. The final circuit is a bit of a test. We combine what we learned about using transistors in CIRC03 to control a relay. A relay is an electrically controlled mechanical switch. Inside the little plastic box is an electromagnet that, when energized, causes a switch to trip (often with a very satisfying clicking sound). You can buy relays that vary in size from a quarter of the size of the one in this kit up to as big as a fridge, each capable of switching a certain amount of current. They are immensely fun because there is an element of the physical to them. While all the silicon we've played with to this point is fun sometimes you just want to wire up a hundred switches to control something magnificent. Relays give you the ability to dream it up then control it with your Arduino. Now to using todays technology to control the past. (The 1N4001 diode is acting as a flyback diode for details on why its there visit: http://ardx.org/4001) 2 Pin Header x4 CIRC-11 Breadboard sheet x1 2.2k Ohm Resistor Red-Red-Red x1 560 Ohm Resistor Green-Blue-Brown x2 Red LED x1 Relay (DPDT) x1 Arduino pin 2 resistor (2.2kohm) gnd (ground) (-) Collector Emitter Base +5 volts Transistor P2N2222AG coil com NC NO Diode (flyback) Diode (1N4001) x1 the transistor will have P2N2222AG printed on it (some variations will have the pin assignment reversed) Transistor P2N2222AG (TO92) x1 Green LED x1 .:download:. breadboard layout sheet http://ardx.org/BBLS11 .:view:. assembling video http://ardx.org/VIDE11 WHAT WE’RE DOING: Parts: The Internet THE CIRCUIT: Schematic

Watch the Back-EMF Pulse Replace the diode with an LED. You’ll see it blink each time it “snubs” the coil voltage spike when it turns off. Controlling a Motor In CIRC-03 we controlled a motor using a transistor. However if you want to control a larger motor a relay is a good option. To do this simply remove the red LED, and connect the motor in its place (remember to bypass the 560 Ohm resistor) Controlling Motor Direction A bit of a complicated improvement to finish. To control the direction of spin of a DC motor we must be able to reverse the direction of current flow through it. To do this manually we reverse the leads. To do it electrically we require something called an h-bridge. This can be done using a DPDT relay to control the motor's direction, wire up the following circuit. It looks complicated but can be accomplished using only a few extra wires. Give it a try. NOT WORKING? (3 things to try) MAKING IT BETTER CODE (no need to type everything in just) MORE, MORE, MORE: No Clicking Sound The transistor or coil portion of the circuit isn't quite working. Check the transistor is plugged in the right way. 29 CIRC-11 File > Sketchbook > Digital > Blink (example from the great arduino.cc site check it out for other great ideas) /* * Blink * * The basic Arduino example. Turns on an LED on for one second, * then off for one second, and so on... We use pin 13 because, * depending on your Arduino board, it has either a built-in LED * or a built-in resistor so that you need only an LED. * * http://www.arduino.cc/en/Tutorial/Blink */ int ledPin = 2; // *********** CHANGE TO PIN 2 ************ void setup() // run once, when the sketch starts { pinMode(ledPin, OUTPUT); // sets the digital pin as output } void loop() // run over and over again { digitalWrite(ledPin, HIGH); // sets the LED on delay(1000); // waits for a second digitalWrite(ledPin, LOW); // sets the LED off delay(1000); // waits for a second } More details, where to buy more parts, where to ask more questions. http://ardx.org/CIRC11 Not Quite Working The included relays are designed to be soldered rather than used in a breadboard. As such you may need to press it in to ensure it works. (and it may pop out occasionally) Nothing Happens The example code uses pin 13 and we have the relay connected to pin 2. Make sure you made this change in the code. Arduino pin 2 resistor (2.2kohm) gnd (ground) (-) Collector Emitter Base +5 volts Transistor P2N2222AG coil com NC NO Diode (flyback)

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