Category Archives: Electronics

Arduino Programming Quick Reference

void setup()
void loop()

Control Structures
if (x<7){} else{}
switch (newvar) {
case 1:
case 2:
for (int i=0; i <=255; i++){}
while (X<7){}
do {} while (x<7);
continue;                                              //Go to next in do, for, while loop
return x;                                               //Or return; for voids
goto                                                       //potentially harmful

More Syntax
// Single line comment
/* MultiLine comment */
#define COUPLE 2
#include <avr/pgmspace.h>

General Operators
= Assignment Operator
+ Addition
– Subtraction
* Multiplication
/ Division
% Modulo
== Equal to
!= Not equal to
< Less than
> Greater than
<= Less then or equal to
>= Greater than or equal to
&& And
|| Or
! Not

Pointer Access
& Reference operator
* Dereference operator

Bitwise Operators
& Bitwise and
| Bitwise or
^ Bitwise xor
~ Bitwise not
<< Bitshift left
>> Bitshift right

Compound Operators
++ Increment
— decrement
+= compound addition
-= compound subtraction
*= Compound multiplication
/= Compound division
&= Compound bitwise and
|= Compound bitwise or

true | false
143                                                   //Decimal number
0173                                               //Octal number
0b11011111                            //Binary
0x7B                                              //Hex number
7U                                                  //Force unsigned
10L                                                //Force long
15UL                                            //Force long unsigned
10.0                                               //Forces floating point
2.4e5                                           //240000

Data Types
boolean                                                                                //0,1,false,true
char (‘a’ -128 to 127)
unsigned char (0 to 255)
byte (0 to 255)
int (-32,768 to 32,767)
unsigned int (0 to 65,535)
word (0 to 655word (0 to 65,535))
long (-2,147,483,648 to 2,147,483,647)
unsigned long                                                                 //0 to 4,294,967,295
float                                                                                    //-3.4028235E+38 to                                                                                                                   3.4028235E+38
double                                                                              //same as float)
sizeof(newint)                                                            //returns 2 bytes

char S1[15];
char S2[9]={‘s,’y,’s’,’r’,’e’,’c’,’o’,’n’};
char S#[9]={‘s,’y,’s’,’r’,’e’,’c’,’o’,’n’,’\0′};               //included \0 null termination
char S4[] = “sysrecon”;
char S5[9] = “sysrecon”;
char S6[15] = “sysrecon”;

int newInts[6];
int newPins[] = {2,4,8,3,6};
int newSensVals[6] = {2,4,-8,3,2};


static                                //persists between calls
volatile                           //use RAM
const                               //make read only
PROGMEM               //use flash

Digital I/O
pinMode(pin, [INPUT,OUTPUT])
digitalWrite(pin, value)
int digitalRead(pin)                                        //Write high to inputs to use                                                                                                 pull up res

Analog I/O
int analogRead(pin)                                    //call twice if switching pins from                                                                                       high Z source
analogWrite(pin, value)                          //PWM

Advanced I/O
tone(pin, freqhz)
tone(pin, feqhz, duration_ms)
shiftOut(dataPin, clockPin, [MSBFIRST, LSBFIRST], value)
unsigned long pulseIn(pin,[HIGH, LOW])

unsigned long mills()                               //50 days overflow
unsigned long micros()                         //70 min overflow

constrain(x, minval, maxval)
map(val, fromL, fromH, toL, toH)
pow(base, exponent)

Random Numbers
randomSeed(seed)                               //Long or int
long random(max)
long random(min,max)

Bits and Bytes
bit(bitn)                                                   //bitn: 0-LSB 7-MSB

External Interrupts
attachInterrupt(interupt, function, [LOW,CHANGE,RISING,FALLING])

begin([300, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200])
int available()
int read()

EEPROM (#include <EEPROM.h>)
byte read(intAddr)
write(intAddr, newByte)

Servo (#include <Servo.h>)
attach(pin, [min_uS, max_uS])
write(angle)                                                           //0-180
writeMicroseconds(uS)                                //1000 – 2000, 1500 is midpoint
read()                                                                       //0-180
attached()                                                            //Returns boolean

SoftwareSerial (#include <SoftwareSerial.h>)
SoftwareSerial(RxPin, TxPin)
begin(longSpeed)                                           //up to 9600
char read()                                                          //blocks till data
print(newData)                                              //or printLn(newData)

Wire (#include <Wire.h>) //For I2C
begin()                                                                //Join as master
begin(addr)                                                     //Join as slave @ addr
requestFrom(addr, count)
beginTransmission(addr)                       //Step 1
send(newByte)                                             //Step 2
send(char * newString)
send(byte * data, size)
endTransmission()                                    //Step 3
byte available()                                           //Num of bytes
byte receive()                                               //Return next byte

Arduino: How To Make An LED Blink

In this tutorial we will make an LED (light emitting diode) blink at specific intervals.

Items you will need:

  • 1 Arduino (UNO or equivalent)
  • 1 USB cable
  • 1 Breadboard
  • 3 connection wires (preferably male-male breadboard jumper wires and in 3 different colors. In this tutorial we will use Black for Ground, Red for 5v and Yellow for Arduino output).
  • 1 LED (light emitting diode) – 5 mm; leg yes; color Red (633nm)
  • 1 330 Ω Resistor – tolerance ±5%; resistance 330Ω

Component notes:

  • Arduino – please refer to “What Is An Arduino?”
  • LED (light emitting diode) – Make sure the short leg, marked with a flat side goes into the negative position (-)
  • 330 Ω Resistor – The color bands should read Orange, Orange, Brown, Gold. The direction of the resistor when placed on the breadboard is irrelevant.

To determine which resistor to use, please check the chart below:

Resistor Color Chart


4 Band Resistor Calculator

 Some resistors have the color bands grouped together  close to one end. Hold the resistor with the closely grouped bands to your left and read the resistor from the left to the right. Also, the first band can’t be silver or gold.


The schematic of the circuit we will be creating is as follows:

Arduino Blink Basic Schematic

Arduino LED Blink Detailed Schematic

Our finished circuit will look as follows:

Arduino Blink Breadboard

  • LED GOES FROM D10(+ anode) TO D11(- cathode)
  • 333O Resistor GOES FROM B11 TO Anywhere on breadboard ground (- GND)
  • Black Jumper Wire GOES FROM Arduino GND TO Breadboard Ground(-)
  • Red Jumper Wire GOES FROM Arduino 5V TO Breadboard Power (+)
  • Yellow Jumper Wire GOES FROM Arduino PIN13 TO Breadboard E10

Now that the circuit is built, we can connect the Arduino to our computer. Once it is connected open up the Arduino Integrated Development Environment (IDE). Before we start adding the code, click on Tools → Board and select the correct Arduino board you are using. Next, click on Tools → Serial Port and select your correct port. Once the IDE is setup enter the code below either by typing, copy and paste or by downloading from


Turns on an LED on for five seconds, then off for five seconds, repeatedly.

This example code is in the public domain.

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);

// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(5000); // wait for 5 seconds
digitalWrite(led, LOW); // turn the LED off by making voltage LOW
delay(5000); // wait for 5 seconds

Once you have entered the code into the IDE, click verify to ensure the code compiles and then click upload to get the sketch onto your Arduino.

Arduino IDE Verify and Upload

After a few seconds the Arduino will restart and you will see the sketch begin to execute.

You should also notice that the Arduino has an LED on-board that will sync to your LED on the breadboard. If you do not have the components to create this circuit, you can still test the source code with the Arduino’s on-board LED.

We hope you enjoyed this Arduino tutorial. Keep checking back as there will be many more to come!

OWI Robotic Arm Edge Plus OWI-535/SOFT USB Interface Kit

Today we are taking a look at the OWI Robotic Arm Edge and OWI-535/SOFT USB Interface with Programmable Software:

OWI Robotic Arm Edge Features:

  • 187 piece kit
  • No Soldering Required
  • Multiple movements and functions
  • Robotic arm gripper opens and closes
  • Radial wrist motion of 120°
  • Extensive elbow range of motion of 300°
  • Base rotation of 270°
  • Base motion of 180°
  • Vertical reach of 15 inches
  • Horizontal reach of 12.6 inches
  • Lifting capacity of 100g
  • Search light on the gripper
  • Audible safety gear indicator is included on all 5 gear boxes to prevent potential injury or gear breakage during operation
  • Manipulation using the “5’s”, five-switch wired controller, 5 motors, 5 gear boxes, and 5 joints
  • Remote requires no extra batteries


  • Costs about $40 on Amazon
  • Requires 4 D-size batteries (not included), get these before you even begin. You will put it together faster than you think(1-3 hours)
  • There are no sensors on the robot
  • There is no gripper rotation
  • Test motors before you assemble in case they are defective in anyway. You do not want to have to take this apart and reassemble
  • Smaller than it looks

OWI-535/SOFT USB Interface with Programmable Software for Robotic Arm Edge

Costs about $35 on Amazon

This package allows you to connect the OWI Robotic Arm Edge to a PC and have real time manual control of the robotic arm and program the arm to perform a sequence of movements.

The USB Interface Kit comes complete with a CD, printed circuit board, USB cable and accessories, and a detailed instruction manual.

NOTE: This software does not have any driver signature so you will have to disable Windows Driver Signature Enforcement in Windows 8. Anyone installing this software in Windows 8 / 8.1 please view our tutorial on “How to install unsigned drivers in Windows 8.1”


OS: Windows XP (SP 1,2,3), Vista and Windows 7.

64-bit Windows is now supported and can be downloaded here:

CPU: Pentium3, 1.0GHz or higher

Memory: 256MB or higher

Hardware Disk Space: 100MB or more

What Is An Arduino?

The Arduino was introduced in 2005 by founders Massimo Banzi, David Cuartielles, Tom Igoe, Gianluca Martino, and David Mellis. The Arduino is not really the board itself or the microprocessor on the board. The Arduino is a hardware/software platform that was designed to provide an inexpensive and easy way for hobbyists, students and professionals to create devices that interact with their environment. The Arduino platform is completely open hardware and open source software.

Arduino boards can be purchased pre-assembled or as do-it-yourself kits. The hardware design information is available for those who would like to assemble an Arduino by hand. The current prices of Arduino boards run around $20-$30 on SparkFun and clones as low as $9 on Amazon

The Arduino platform is a single-board microcontroller designed around an 8-bit Atmel AVR microcontroller, or a 32-bit Atmel ARM. Official Arduinos have used the megaAVR series of chips, specifically the ATmega8, ATmega168, ATmega328, ATmega1280, and ATmega2560. Most boards include a 5 volt linear regulator and a 16 MHz crystal oscillator.

The Arduino platfrom feature a USB interface, 6 analog input pins, as well as 14 digital I/O pins (six of which can produce pulse-width modulated signals) which allows the user to attach various interchangeable add-on modules known as shields or basic breadboards. Many shields are individually addressable via an I²C serial bus, allowing many shields to be stacked and used in parallel. Shields or jumper wires to a breadboard are plugged into the top of the board, via female 0.10-inch (2.5 mm) headers. The Arduino has a number of facilities for communicating with a computer, another Arduino, or other microcontrollers

The Arduino’s microcontroller is also pre-programmed with a boot loader that simplifies uploading of programs to the on-chip flash memory, compared with other devices that typically need an external programmer. Arduino boards are programmed via USB over an RS-232 serial connection implemented using USB-to-serial adapter chips such as the FTDI FT232

The Arduino Platform comes with a simple down-loadable, cross-platform, integrated development environment (IDE) written in JAVA and allows users to write programs for Arduino using C or C++. The code you write is C/C++ syntax but not a valid C/C++ program. An extra include header at the top and a very simple main() function at the bottom, to make it a valid C++ program. The IDE is derived from the IDE for the Processing programming language and the Wiring development platform and contains a C/C++ library called “Wiring”. Wiring was based on the original work done on Processing project in MIT. The Wiring IDE uses the GNU toolchain and AVR Libc to compile programs, and uses avrdude to upload programs to the board. You can program the arduino in standard C using avrstudio and upload with avrdude.

Programming in the Arduino IDE is as simple as creating 2 functions()
1. setup() – a function run once at start up that can be used to define initial environment settings
2. loop() – a function called repeatedly until the board is powered off

A simple program to blink the Arduino LED

Turns on an LED on for one second, then off for one second, repeatedly.

This example code is in the public domain.

// Pin 13 has an LED connected on most Arduino boards.
// give it a name:
int led = 13;

// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);

// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second

We have hundreds of tutorials in mind for the Arduino Developemnt Platform. We will begin to produce them soon so keep checking back.

For more information right now, check out the offical Arduino page at be sure to check out the Arduino playground which has tons of information to get you started.