An introduction to working with the LED, OLED, and LDR components in Arduino GROVE. A program for Arduino to measure light intensity, turn LED on/off, and display info to an OLED screen.
Source
/* Arduino Grove Program that reads in data from Light sensor, turns LED on/off and displays info on OLED screen
https://eyecode4you.wordpress.com/
Arduino IDE v1.8.9
Based on: https://wiki.seeedstudio.com/Grove-OLED_Display_1.12inch/
Using U8x8 Graphics library: https://github.com/olikraus/u8g2/wiki/u8x8reference
*/
#include <Arduino.h>
#include <U8x8lib.h>
U8X8_SSD1306_128X64_NONAME_HW_I2C u8x8(/* reset=*/ U8X8_PIN_NONE);
// U8X8_SSD1306_128X64_NONAME_SW_I2C u8x8(/* clock=*/ SCL, /* data=*/ SDA, /* reset=*/ U8X8_PIN_NONE); // OLEDs without Reset of the Display
const int ledPin=4; //Constant we use for the GROVE LED (Pin 4 on the board)
const int thresholdvalue=10; //The threshold on the Light sensor for which the LED should turn on.
float Rsensor; //Resistance of sensor in K
void intro(){ //print initial message to OLED
u8x8.clear(); //clear OLED screen
u8x8.setInverseFont(1);
u8x8.draw1x2String(4, 2, "Light");
delay(500); //(half second delay)
u8x8.draw1x2String(2, 4, "Intensity!");
delay(500);
u8x8.setInverseFont(0);
}
void night(int Rsensor){ //Low light intensity
char buffer [30]; //for int to string conversion with itoa()
u8x8.clear();
u8x8.draw1x2String(5, 0, itoa(Rsensor, buffer, 10));
delay(25);
u8x8.draw1x2String(5, 2, "Night");
delay(25);
u8x8.draw1x2String(5, 4, "Time!");
delay(250);
}
void day(int Rsensor){ //High light intensity
char buffer [30]; //for int to string conversion with itoa()
u8x8.clear();
u8x8.draw1x2String(5, 0, itoa(Rsensor, buffer, 10));
delay(25);
u8x8.draw1x2String(5, 2, "Day");
delay(25);
u8x8.draw1x2String(5, 4, "Time!");
}
void setup() {
Serial.begin(9600); //Start the Serial connection
pinMode(ledPin,OUTPUT); //Set the LED as an OUTPUT. Pin = 4 (From our const above!)
u8x8.begin();
u8x8.setFlipMode(1);
}
void loop() {
int sensorValue = analogRead(6); //create var for light sensor
Rsensor=(float)(1023-sensorValue)*10/sensorValue;
u8x8.setFont(u8x8_font_chroma48medium8_r); //set OLED font
intro();//Intro message
if(Rsensor>thresholdvalue)
{
digitalWrite(ledPin,HIGH); //Turn LED on
for(int i=0; i<1; i++){
night(Rsensor);
}
}
else
{
digitalWrite(ledPin,LOW); //Turn LED off
for(int i=0; i<1; i++){
day(Rsensor);
}
}
delay(2000);//delay for 2 seconds
}//end main loop
Download Code: GitHub
Program Run-Through
WHEN IN THE DARK, LED TURNS ON AND NIGHT TIME IS PRINTED TO SCREEN
An output of High or Low (On or Off) is sent to the LED (Pin Digital 4)
WHEN IN THE LIGHT, LED TURNS OFF AND DAY TIME IS PRINTED TO SCREEN
On this board, light is received by Light Sensor
(Pin Analog 6 – Top right)
Further Reading
Arduino Grove OLED Display Setup: https://wiki.seeedstudio.com/Grove-OLED_Display_1.12inch/
u8x8 Graphics Library Reference: https://github.com/olikraus/u8g2/wiki/u8x8reference