## Large Size Bar-Graph Voltage Monitor Using Arduino Mega and 20 Segment 3W White LED

Simple 20 LED  Bar-Graph Voltmeter , each LED display 0.25V, this circuit can measure 5V directly or its can measure higher voltage range using resistor divider.

Example circuit for resistor divider. If choose Z1=10K and Z2-10K it can measure 0-10V.

Turns on a series of LEDs based on the value of an analog voltage input.  This is a simple way to make a bar graph display. Though this graph uses 20 LEDs, you can use any number by changing the LED count and the pins in the array. This method can be used to control any series of digital outputs that depends on an analog input.

The bar graph – a series of LEDs in a line, such as you see on an audio display – is a common hardware display for analog sensors. It’s made up of a series of LEDs in a row, an analog input like a Potentiometer, and a little code in between. You can buy multi-LED bar graph displays fairly cheaply, like this one. This tutorial demonstrates how to control a series of LEDs in a row, but can be applied to any series of digital outputs.

Watch Video Of This Project

Arduino Code

/*
* 20 LED Bargraph Meter , code, schematic, PCB layout
available at our website www.twovolt.com

*/

// these constants won’t change:
const int analogPin = A0; // the pin that the potentiometer is attached to
const int ledCount = 20; // the number of LEDs in the bar graph

int ledPins[] = {
22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
}; // an array of pin numbers to which LEDs are attached

void setup() {
// loop over the pin array and set them all to output:
for (int thisLed = 0; thisLed < ledCount; thisLed++) {
pinMode(ledPins[thisLed], OUTPUT);
}
}

void loop() {
// map the result to a range from 0 to the number of LEDs:
int ledLevel = map(sensorReading, 0, 1023, 0, ledCount);

// loop over the LED array:
for (int thisLed = 0; thisLed < ledCount; thisLed++) {
// if the array element’s index is less than ledLevel,
// turn the pin for this element on:
if (thisLed < ledLevel) {
digitalWrite(ledPins[thisLed], HIGH);
}
// turn off all pins higher than the ledLevel:
else {
digitalWrite(ledPins[thisLed], LOW);
}
}
}

## Dark Sensitive Interactive Light Using 20 Segment Bar-Graph and Arduino

The Project is based on 20 Segment Bar Graph (2X10 LED PCB), Arduino Mega and LDR, The project converts darkness in to number of LEDs, number of LEDs will glow proportional to darkness falls on LDR. Circuit works with 12V DC and draw 4 Amps while all LEDs are ON. Digital pin D22 to D41 of Arduino used to driver LEDs.

Watch Video Of This Project

Arduino Code

/*
* Dark Sensitive interactive LED Light , The project consist 20 segment Bar-graph white LEDs ,
* Driver transistors for LEDs, LDR, Pull Resistor for LDR and arduino mega
* Code writen for arduino mega, Arduino code, schematic, PCB layout
available at our website www.twovolt.com, This also can be used as dark senst

*/

// these constants won’t change:
const int analogPin = A0; // the pin that the potentiometer is attached to
const int ledCount = 20; // the number of LEDs in the bar graph

int ledPins[] = {
22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
}; // an array of pin numbers to which LEDs are attached

void setup() {
// loop over the pin array and set them all to output:
for (int thisLed = 0; thisLed < ledCount; thisLed++) {
pinMode(ledPins[thisLed], OUTPUT);
}
}

void loop() {
// map the result to a range from 0 to the number of LEDs:
int ledLevel = map(sensorReading, 350, 950, 0, ledCount);

// loop over the LED array:
for (int thisLed = 0; thisLed < ledCount; thisLed++) {
// if the array element’s index is less than ledLevel,
// turn the pin for this element on:
if (thisLed < ledLevel) {
digitalWrite(ledPins[thisLed], HIGH);
}
// turn off all pins higher than the ledLevel:
else {
digitalWrite(ledPins[thisLed], LOW);
}
}
}

## 10X3W White LED Knight Rider Effect ( Arduino Uno)

Simple Project provide knight rider effect with help of 10X3W white LEDs and Arduino Uno, LED connected to D2 to D11 pins of Arduino.

Arduino Pins Vs LED

• D2>>LED1
• D3>>LED2
• D4>>LED3
• D5>>LED4
• D6>>LED5
• D7>>LED6
• D8>>LED7
• D9>>LED8
• D10>>LED9
• D11>>LED10

Arduino Code

/*
Simple code generate knight rider effect using 10 white LEDs,
Code presented  here is a modification of original code from electroschematics Author P-Marian

*/
int del=50; // sets a default delay time
void setup() {
// initialize the digital pins as outputs:
for (int i = 2; i<=11 ; i++) {
pinMode(i, OUTPUT);
} // end of for loop
} // end of setup

void loop() {
for (int i = 2; i<=11; i++) { // blink from LEDs 2 to 11
digitalWrite(i, HIGH);
delay(del);
digitalWrite(i, LOW);
}
for (int i = 11; i>=3; i–) { // blink from LEDs 11 to 3
digitalWrite(i, HIGH);
delay(del);
digitalWrite(i, LOW);
}
}

## LED Sequencer Using 10 White LEDs of Each 3W and Arduino

The 10 LED sequencer circuit published here is based on Arduino Uno and 10 White LED board. The project contains 10 LEDs of each 3W, provides high intensity, can be used in various applications. The board can be connected to Arduino Uno, Arduino Mega, Arduino Nano or Raspberry Pai , each LED can be controlled individually, I have connected LEDs to pin D2-D11 of Arduino. LED board required supply 5V DC, it can work with higher  supply by changing current resistor across LEDs, Large size Bar-graph monitor, led sequencer, strobe, LED light effects are possible applications with this board.

Note : Dont Power Up the LED Board from Arduino, LED board required separate 5V DC 3Amps.

Video Of this Project

Features

• Supply 5V DC
• Maximum Load on each channel 300mA-400mA (Total 3Amps)
• LED 1-10 Connected to D2,D3,D4,D5,D6,D7,D8,D9,D10,D11 of Arduino

The 10X3W White LED board has been designed to create large size barograph meter and light effects generator.  The board contains 3W LEDs, D-Pak transistor as driver and current limiting resistor across each LED. Circuit works with 5V, each LED take approx. 300mA-400mA current, each LED can be controlled individually by applying TTL voltage, header connector provided to interface micro-controller. LED dimmer possible by applying PWM signal to each LED, Easy interface with Arduino.

Arduino Code for LED Sequencer

/* A simple program to sequentially turn on and turn off 10 LEDs
Code tested on 10X3W white LED board works with 5V DC,
all LEDs take approx 2Amp current, PCB Design , Schematic
website www.twovolt.com */

int LED1 = 2;
int LED2 = 3;
int LED3 = 4;
int LED4 = 5;
int LED5 = 6;
int LED6 = 7;
int LED7 = 8;
int LED8 = 9;
int LED9 = 10;
int LED10 = 11;

void setup() {
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(LED4, OUTPUT);
pinMode(LED5, OUTPUT);
pinMode(LED6, OUTPUT);
pinMode(LED7, OUTPUT);
pinMode(LED8, OUTPUT);
pinMode(LED9, OUTPUT);
pinMode(LED10, OUTPUT);

}

void loop() {
digitalWrite(LED1, HIGH);
delay(60);
digitalWrite(LED2, HIGH);
delay(60);
digitalWrite(LED3, HIGH);
delay(60);
digitalWrite(LED4, HIGH);
delay(60);
digitalWrite(LED5, HIGH);
delay(60);
digitalWrite(LED6, HIGH);
delay(60);
digitalWrite(LED7, HIGH);
delay(60);
digitalWrite(LED8, HIGH);
delay(60);
digitalWrite(LED9, HIGH);
delay(60);
digitalWrite(LED10, HIGH);
delay(60);
digitalWrite(LED1, LOW);
delay(60);
digitalWrite(LED2, LOW);
delay(60);
digitalWrite(LED3, LOW);
delay(60);
digitalWrite(LED4, LOW);
delay(60);
digitalWrite(LED5, LOW);
delay(60);
digitalWrite(LED6, LOW);
delay(60);
digitalWrite(LED7, LOW);
delay(60);
digitalWrite(LED8, LOW);
delay(60);
digitalWrite(LED9, LOW);
delay(60);
digitalWrite(LED10, LOW);
delay(60);

}

## 10X 3W LED Board For Large Bar-Graph Meter/Light Effects

The 10X3W White LED board has been designed to create large size bar-graph meter and light effects generator.  The board contains 3W LEDs, D-Pk MJD44H11 transistor as driver and current limiting resistor across each LED. Circuit works with 5V, each LED take approx. 300mA-400mA current, each LED can be controlled individually by applying TTL voltage, header connector provided to interface micro-controller, Ardunio, Raspberry Pi etc.  . LED dimmer possible by applying PWM signal to each LED, Easy interface with Arduino.

## Arduino Nano Blink and Buzz Project Using 11 LEDs & Buzzer

Another project using Arduino Nano 11 LEDs and buzzer shield, LEDs connected  to D2-D12 of Arduino Nano and buzzer connected to D13 of Arduino Nano,  Simple example code flashing at speed of 100mili seconds on/off.

Watch Video On You Tube

Schematic

PCB TOP LAYER

PCB LAYOUT

Arduino Code

/*

Turns on LEDS & Buzzer for 100 Mili seconds,
then off 100 Mili seconds, repeatedly.
This example code is based on example code
that is in the public domain.
*/
void setup() {
// initialize the digital pin as an output.
// Pin 2-11 has LEDs & Pin 13 has buzzer connected on Arduino:
pinMode(2, OUTPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
pinMode(5, OUTPUT);
pinMode(6, OUTPUT);
pinMode(7, OUTPUT);
pinMode(8, OUTPUT);
pinMode(9, OUTPUT);
pinMode(10, OUTPUT);
pinMode(11, OUTPUT);
pinMode(12, OUTPUT);
pinMode(13, OUTPUT);
}
void loop() {
digitalWrite(2, HIGH); // set the LED on
digitalWrite(3, HIGH); // set the LED on
digitalWrite(4, HIGH); // set the LED on
digitalWrite(5, HIGH); // set the LED on
digitalWrite(6, HIGH); // set the LED on
digitalWrite(7, HIGH); // set the LED on
digitalWrite(8, HIGH); // set the LED on
digitalWrite(9, HIGH); // set the LED on
digitalWrite(10, HIGH); // set the LED on
digitalWrite(11, HIGH); // set the LED on
digitalWrite(12, HIGH); // set the LED on
digitalWrite(13, HIGH); // set the Buzzer on
delay(100); // wait for a second
digitalWrite(2, LOW); // set the LED off
digitalWrite(3, LOW); // set the LED off
digitalWrite(4, LOW); // set the LED off
digitalWrite(5, LOW); // set the LED off
digitalWrite(6, LOW); // set the LED off
digitalWrite(7, LOW); // set the LED off
digitalWrite(8, LOW); // set the LED off
digitalWrite(9, LOW); // set the LED off
digitalWrite(10, LOW); // set the LED off
digitalWrite(11, LOW); // set the LED off
digitalWrite(12, LOW); // set the LED off
digitalWrite(13, LOW); // set the Buzzer off
delay(100); // wait for a second
}

## Light Effects and Sound Effects Arduino Nano

Light Effects and Sound Effects Arduino Nano shield, shield contains 11 LEDs ,one buzzer and INA198 current measurement , shield can be used to develop various projects like LED Bar-graph Volt Meter, Bar-Graph Current Meter, LED light effects, Warning light and sound.

• Supply 5V DC
• 11 LEDS Connected to D2-D12 Digital Pins Of Arduino Nano
• Buzzer Connected to Digital Pin D13 to Arduino

ARDUINO CODE

*/

int led = 13;
int led2 = 2;
int led3 = 3;
int led4 = 4;
int led5 = 5;
int led6 = 6;
int led7 = 7;
int led8 = 8;
int led9 = 9;
int led10 = 10;
int led11 = 11;
int led12 = 12;

// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
pinMode(led2, OUTPUT);
pinMode(led3, OUTPUT);
pinMode(led4, OUTPUT);
pinMode(led5, OUTPUT);
pinMode(led6, OUTPUT);
pinMode(led7, OUTPUT);
pinMode(led8, OUTPUT);
pinMode(led9, OUTPUT);
pinMode(led10, OUTPUT);
pinMode(led11, OUTPUT);
pinMode(led12, OUTPUT);

}

// the loop routine runs over and over again forever:
void loop() {
digitalWrite(led, HIGH);
delay(50);
digitalWrite(led, LOW);
delay(100);
digitalWrite(led, HIGH);
delay(90);
digitalWrite(led, LOW);
delay(60);
digitalWrite(led, HIGH);
delay(150);
digitalWrite(led, LOW);
delay(20);
digitalWrite(led, HIGH);
delay(120);
digitalWrite(led, LOW);
delay(70);
digitalWrite(led, HIGH);
delay(10);
digitalWrite(led, LOW);
delay(50);
digitalWrite(led, HIGH);
delay(250);
digitalWrite(led, LOW);
delay(90);
digitalWrite(led, HIGH);
delay(100);
digitalWrite(led, LOW);
delay(130);
digitalWrite(led, HIGH);
delay(20);
digitalWrite(led, LOW);
delay(90);
{digitalWrite(led2, HIGH);
delay(100);
digitalWrite(led2, LOW);
delay(100);}
{digitalWrite(led4, HIGH);
delay(100);
digitalWrite(led4, LOW);
delay(100);}// wait
{digitalWrite(led5, HIGH);
delay(100);
digitalWrite(led5, LOW);
delay(100);}// wait
{digitalWrite(led6, HIGH);
delay(100);
digitalWrite(led6, LOW);
delay(100);}// wait
{digitalWrite(led7, HIGH);
delay(100);
digitalWrite(led7, LOW);
delay(100);}// wait for a second
{digitalWrite(led8, HIGH);
delay(100);
digitalWrite(led8, LOW);
delay(100);}// wait
{digitalWrite(led9, HIGH);
delay(100);
digitalWrite(led9, LOW);
delay(100);}// wait
{digitalWrite(led10, HIGH);
delay(100);
digitalWrite(led10, LOW);
delay(100);}// wait
{digitalWrite(led11, HIGH);
delay(100);
digitalWrite(led11, LOW);
delay(100);}// wait
{digitalWrite(led12, HIGH);
delay(100);
digitalWrite(led12, LOW);
delay(100);}// wait
}

## LED SEQUENCER USING 11 LED WITH BUZZER SOUND USING ARDUINO NANO

LED SEQUENCER USING 11 LED WITH BUZZER SOUND USING ARDUINO NANO,

Light Effects and Sound Effects Arduino Nano shield, shield contains 11 LEDs ,one buzzer and INA198 current measurement , shield can be used to develop various projects like LED Bar-graph Volt Meter, Bar-Graph Current Meter, LED light effects, Warning light and sound.

• Supply 5V DC
• 11 LEDS Connected to D2-D12 Digital Pins Of Arduino Nano
• Buzzer Connected to Digital Pin D13 to Arduino

Note : Don’t populate parts showan in doted box

11 LED SEQUENCER WITH SOUND ARDUINO NANO SCHEMATIC

11 LED SEQUENCER WITH SOUND ARDUINO NANO PCB TOP LAYER

ARDUINO CODE FOR 11 LED SEQUENCER AND BUZZER WARNING

*/

int led2 = 2; // LED connected to digital pin 2
int led3 = 3; // LED connected to digital pin 3
int led4 = 4; // LED connected to digital pin 4
int led5 = 5; // LED connected to digital pin 5
int led6 = 6; // LED connected to digital pin 6
int led7 = 7; // LED connected to digital pin 7
int led8 = 8; // LED connected to digital pin 8
int led9 = 9; // LED connected to digital pin 9
int led10 = 10; // LED connected to digital pin 10
int led11 = 11; // LED connected to digital pin 11
int led12 = 12; // LED connected to digital pin 12
int led13 = 13; // BUZZER connected to digital pin 13

void setup()
{
pinMode(led2, OUTPUT); // sets the digital pin as output LED
pinMode(led3, OUTPUT); // sets the digital pin as output LED
pinMode(led4, OUTPUT); // sets the digital pin as output LED
pinMode(led5, OUTPUT); // sets the digital pin as output LED
pinMode(led6, OUTPUT); // sets the digital pin as output LED
pinMode(led7, OUTPUT); // sets the digital pin as output LED
pinMode(led8, OUTPUT); // sets the digital pin as output LED
pinMode(led9, OUTPUT); // sets the digital pin as output LED
pinMode(led10, OUTPUT); // sets the digital pin as output LED
pinMode(led11, OUTPUT); // sets the digital pin as output LED
pinMode(led12, OUTPUT); // sets the digital pin as output LED
pinMode(led13, OUTPUT); // sets the digital pin as output BUZZER
}

void loop()
{
digitalWrite(led2, HIGH);
delay(100);
digitalWrite(led2, LOW);
delay(100);
digitalWrite(led3, HIGH);
delay(100);
digitalWrite(led3, LOW);
delay(100);
digitalWrite(led4, HIGH);
delay(100);
digitalWrite(led4, LOW);
delay(100);
digitalWrite(led5, HIGH);
delay(100);
digitalWrite(led5, LOW);
delay(100);
digitalWrite(led6, HIGH);
delay(100);
digitalWrite(led6, LOW);
delay(100);
digitalWrite(led7, HIGH);
delay(100);
digitalWrite(led7, LOW);
delay(100);
digitalWrite(led8, HIGH);
delay(100);
digitalWrite(led8, LOW);
delay(100);
digitalWrite(led9, HIGH);
delay(100);
digitalWrite(led9, LOW);
delay(100);
digitalWrite(led10, HIGH);
delay(100);
digitalWrite(led10, LOW);
delay(100);
digitalWrite(led11, HIGH);
delay(100);
digitalWrite(led11, LOW);
delay(100);
digitalWrite(led12, HIGH);
delay(100);
digitalWrite(led12, LOW);
delay(100);
digitalWrite(led13, HIGH);
delay(100);
digitalWrite(led13, LOW);
delay(100);
}

## ARDUINO NANO LED WARNING LIGHT WITH BUZZER 11 LED SEQUENCER

Project published here is simple 11 LED and Buzzer shield for Arduino Nano, shield can be used as bar-graph monitor, buzzer sound effects, the simple example code used to show warning LED including buzzer sound. Circuit works with 5V DC. Shield also provided current sensor circuit which is no use in this project can be abandon. All LEDs 1206 SMD, All resistor are 0805 SMD.

Light Effects and Sound Effects Arduino Nano shield, shield contains 11 LEDs ,one buzzer and INA198 current measurement , shield can be used to develop various projects like LED Bar-graph Volt Meter, Bar-Graph Current Meter, LED light effects, Warning light and sound.

• Supply 5V DC
• 11 LEDS Connected to D2-D12 Digital Pins Of Arduino Nano
• Buzzer Connected to Digital Pin D13 to Arduino

Note : Don’t populate the parts shown in doted box, those parts can be used for current measurement.

11 LED AND BUZZER ARDUINO SHIELD FOR NANO SCHEMATIC

11 LEDs and Buzzer Warning Light Arduino Code, 11 LED Sequencer Arduino Code

LEDs Connected to Pin D2-D12 and Buzzer Connected to D13

/* A simple program to sequentially turn on and turn off 11 LEDs and Sound Buzzer */

int LED1 = 13;
int LED2 = 12;
int LED3 = 11;
int LED4 = 10;
int LED5 = 9;
int LED6 = 8;
int LED7 = 7;
int LED8 = 6;
int LED9 = 5;
int LED10 = 4;
int LED11 = 3;
int LED12 = 2;

void setup() {
pinMode(LED1, OUTPUT);
pinMode(LED2, OUTPUT);
pinMode(LED3, OUTPUT);
pinMode(LED4, OUTPUT);
pinMode(LED5, OUTPUT);
pinMode(LED6, OUTPUT);
pinMode(LED7, OUTPUT);
pinMode(LED8, OUTPUT);
pinMode(LED9, OUTPUT);
pinMode(LED10, OUTPUT);
pinMode(LED11, OUTPUT);
pinMode(LED12, OUTPUT);
}

void loop() {
digitalWrite(LED1, HIGH);
delay(60);
digitalWrite(LED2, HIGH);
delay(60);
digitalWrite(LED3, HIGH);
delay(60);
digitalWrite(LED4, HIGH);
delay(60);
digitalWrite(LED5, HIGH);
delay(60);
digitalWrite(LED6, HIGH);
delay(60);
digitalWrite(LED7, HIGH);
delay(60);
digitalWrite(LED8, HIGH);
delay(60);
digitalWrite(LED9, HIGH);
delay(60);
digitalWrite(LED10, HIGH);
delay(60);
digitalWrite(LED11, HIGH);
delay(60);
digitalWrite(LED12, HIGH);
delay(60);
digitalWrite(LED1, LOW);
delay(60);
digitalWrite(LED2, LOW);
delay(60);
digitalWrite(LED3, LOW);
delay(60);
digitalWrite(LED4, LOW);
delay(60);
digitalWrite(LED5, LOW);
delay(60);
digitalWrite(LED6, LOW);
delay(60);
digitalWrite(LED7, LOW);
delay(60);
digitalWrite(LED8, LOW);
delay(60);
digitalWrite(LED9, LOW);
delay(60);
digitalWrite(LED10, LOW);
delay(60);
digitalWrite(LED11, LOW);
delay(60);
digitalWrite(LED12, LOW);
delay(60);
}

## Constant Current Laser Diode Driver Using OPA2350 OP-AMP

The voltage-controlled current source circuit can be used to drive a constant current into a signal or pump laser diode. This simple linear driver provides a cleaner drive current into a laser diode than switching PWM drivers. The basic circuit is that of a Howland current pump with a current booster (Q1) on the output of a R-R CMOS OPA2350 op amp (U1). Laser diode current is sensed by differentially measuring the voltage drop across a shunt resistor (RSHUNT) in series with the laser diode. The output current is controlled by the input voltage (VIN) that comes from Trim pot PR1.

Features,

• Supply 3,3V DC