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In this lesson we learn about relay and how it functions. Then give example of electromagnet and how relay function internally. The wiring of a relay module is shown and code is explained.
/*
Lesson 67: Arduino code for 4x3 keypad with 8 channel relay
* Library taken : https://playground.arduino.cc/Code/Keypad
* This is the Arduino code for 4x3 keypad with 8 channel relay
Watch instruction video for this code: https://youtu.be/dkESWpdDBYk
* *
* written by Ahmad Shamshiri for Robojax.com
* on Feb 04, 2019 at 18:01 in Ajax, Ontario, Canada
This video is part of Arduino Step by Step Course which starts here: https://youtu.be/-6qSrDUA5a8
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content like this. You can support me on Patreon http://robojax.com/L/?id=63
or make donation using PayPal http://robojax.com/L/?id=64
* * This code is "AS IS" without warranty or liability. Free to be used as long as you keep this note intact.*
* This code has been download from Robojax.com
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
/* @file HelloKeypad.pde
|| @version 1.0
|| @author Alexander Brevig
|| @contact alexanderbrevig@gmail.com
||
|| @description
|| | Demonstrates the simplest use of the matrix Keypad library.
|| #
*/
// start of keypad settings
#include
const byte ROWS = 4; //four rows
const byte COLS = 3; //three columns
char keys[ROWS][COLS] = {
{'1','2','3'},
{'4','5','6'},
{'7','8','9'},
{'*','0','#'}
};
byte rowPins[ROWS] = {2, 3, 4, 5}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {6,7,8}; //connect to the column pinouts of the keypad
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
// end of keypad settings
// start of relay settings
const int relayPin[]={9,10,11,12, 13, 14, 15, 16};// output pins where 8 relays will be connected
String relayNames[] ={"CH1", "CH2","CH3","CH4","CH5","CH6","CH7","CH8"};// Just put name for 8 relays
// do not change lines bellow
int pushed[] ={0,0,0,0, 0,0,0,0};// status of each buttons
int relayStatus[] ={HIGH,HIGH,HIGH,HIGH, HIGH,HIGH,HIGH,HIGH};// initial status of relay
// end of relay settings
void setup(){
// Robojax 4x3 keypad with 8ch Relay test
Serial.begin(9600);
for(int i=0; i<8; i++)
{
pinMode(relayPin[i], OUTPUT); // set relay pins as output
digitalWrite(relayPin[i], HIGH);// initial relay status to be OFF
}
Serial.println("Robojax 8 channel relay keypad");
}
void loop(){
// Robojax 4x3 keypad with 8ch Relay test
int val;
int knum;
char key = keypad.getKey();
// just print the pressed key
if(key && key !='*' && key !='#' && key !='0' && key !='9' ){
knum = (int)key-49;// convert char to integer (one less)
if(knum>=0 && knum<8){
//Serial.println(knum);
if(relayStatus[knum] == LOW){
pushed[knum] = 1-pushed[knum];
delay(50);
}// if
controlRelay(knum);// turn relay ON or OFF
}
}else{
val = LOW;
}
if(knum>=0 && knum<8){
relayStatus[knum] = val;
}
delay(50);
}// loop end
/*
*
* @brief Turns the relay ON or OFF
* @param relayPin is integer pin of relay
* @return no return value
* Written by Ahmad Shamshiri for Robojax.com
*/
void controlRelay(int number)
{
if(pushed[number] == 1)
{
digitalWrite(relayPin[number], LOW);// Turn ON relay
Serial.print(relayNames[number]);
Serial.println(" ON");
}else{
digitalWrite(relayPin[number], HIGH); // turn OFF
Serial.print(relayNames[number]);
Serial.println(" OFF");
}
// Robojax 4x3 keypad with 8ch Relay test
}//controlRelay end
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