The circuit shown here uses a NPN transistor connected to a an Arduino output pin to switch an LED pin. In real life you would perhaps switch a relay, lamp , fan or a buzzer. A darlington transistor could be …

Ultrasonic transducers or ultrasonic sensors are a type of acoustic sensor divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, and transceivers can both transmit and receive ultrasound. …

This example switches on all the LEDs on a 8×8 LED matrix, the matrix is controlled by a MAX7219 You will need the Led Control library #include “LedControl.h” /* Max7219_pinCLK = 10; Max7219_pinCS = 9; Max7219_pinDIN = 8; */ LedControl …

In the following example we will demonstrate the HC-SR501 PIR sensor, this sensor has many nice features including the ability to be driven by 5v, low cost (£2 to £3), it has a decent range (7 metres) and a fairly small size. These …

Connect an LED to digital pin 3 Code [c] void setup() { pinMode(3, OUTPUT); } void loop() { for (int a = 0 ; a < 256 ; a++) { analogWrite(3, a); delay(5); } for (int a = 255 ; …

A reed switch is a small device that when the device is exposed to a magnetic field, the two materials inside the switch pull together and the switch closes. When the magnetic field is removed, the two materials then separate …

This example shows how to interface a basic touch sensor to our arduino, this sensor came as part of a kit of 37 sensors. Touching the metal sensor pin produces an output at the ‘DO’ pin. The output is not …

In this example we will create a basic library, a few examples on this site flash LEDs. We will create a library that will contain a couple of functions, we will then use these in our sample sketch. You need …

This example uses the BMP05 Barometric, pressure and Temperature sensor. It requires the BMP085 library from adafruit. This is a nice little sensor.   [c] #include <Wire.h> #include <Adafruit_BMP085.h> Adafruit_BMP085 bmp; void setup() { Serial.begin(9600); if (!bmp.begin()) { Serial.println(“Could not …

This was a quick test for a multi color LED. Pins 2, 3 and 4 were used   [c] int red = 2; int green =3; int blue =4; int j; void setup() { pinMode(red,OUTPUT); pinMode(green,OUTPUT); pinMode(blue,OUTPUT); } void loop() …

random LEDs on using the LOLShield and an Arduino   Switch LEDS off and on by column [c] #include <Charliplexing.h> void setup() { LedSign::Init(); // initializes the screen } void loop() { for (int x=0; x<14; x++) { for (int …

The LoL Shield is a charlieplexed LED matrix for the Arduino. The LEDs are individually addressable, so you can use it to display anything in a 9×14 grid. Scroll text, play games, display images, or anything else you want to …