Hi all! I made a 10W LED Color and Brightness controller for my own use. despite it works well, there's a problem.
I use 12V SMPS to power LED module, and when I turn on SMPS, at that instant, LED turns on and off very quickly.
despite I added a relay module to solve this problem, but it seems like that both NO - COM and NC - COM are short when module is not powered with 5V VCC.
(1) Why this happens?
(2) How Can I prevent LED turning on right after supplying 12V input, and before arduino is on?
[video]
[schematics of project]
[arduino code]
#include <FastLED.h>
#define LED_R 9
#define LED_G 10
#define LED_B 11
#define STRIP_DIN 6
#define STRIP_LED_NUM 21
#define POT_R A1
#define POT_G A0
#define POT_B A2
#define PUSH_1 12
#define PUSH_2 13
#define RELAY 2
CRGB led[STRIP_LED_NUM];
bool push1_pressed_now = false;
bool push1_pressed_before = false;
bool push2_pressed_now = false;
bool push2_pressed_before = false;
bool led_on = false;
bool strip_on = true;
// Timing variables
unsigned long previousMillis = 0; // Stores the last time LEDs were updated
const long interval = 100; // Interval at which to update LEDs (in milliseconds)
// Stores previous potentiometer values to detect changes
int prev_pot_R_val = 0;
int prev_pot_G_val = 0;
int prev_pot_B_val = 0;
bool is_button_pressed(int button_no, bool &check_now, bool &check_before);
void setup() {
Serial.begin(9600);
// Initialize pins
pinMode(LED_R, OUTPUT);
pinMode(LED_G, OUTPUT);
pinMode(LED_B, OUTPUT);
pinMode(POT_R, INPUT);
pinMode(POT_G, INPUT);
pinMode(POT_B, INPUT);
pinMode(PUSH_1, INPUT_PULLUP);
pinMode(PUSH_2, INPUT_PULLUP);
FastLED.addLeds<WS2812B, STRIP_DIN>(led, STRIP_LED_NUM);
for (int i = 0; i < STRIP_LED_NUM; i++) {
led[i] = CRGB::White;
FastLED.show();
delay(50);
}
pinMode(RELAY, OUTPUT);
// Adjust PWM frequency to 100 Hz
// For Timer1 (pins 9, 10), set prescaler to 1024
// This changes the PWM frequency from 490 Hz to approximately 61 Hz (16MHz / 1024 / 256)
// To get as close to 100 Hz as possible, use prescaler 256 (approximately 244 Hz)
TCCR1B = (TCCR1B & 0b11111000) | 0x04; // CS12 = 1, CS11 = 0, CS10 = 0 for prescaler of 256
// For Timer2 (pins 3, 11), set prescaler to 1024
// This changes the PWM frequency from 980 Hz to approximately 61 Hz (16MHz / 1024 / 256)
// To get as close to 100 Hz as possible, use prescaler 256 (approximately 244 Hz)
TCCR2B = (TCCR2B & 0b11111000) | 0x06; // CS22 = 1, CS21 = 1, CS20 = 0 for prescaler of 256
}
void loop() {
unsigned long currentMillis = millis(); // Get the current time
// Check for button presses
if (is_button_pressed(PUSH_1, push1_pressed_now, push1_pressed_before)) {
led_on = !led_on;
}
if (is_button_pressed(PUSH_2, push2_pressed_now, push2_pressed_before)) {
strip_on = !strip_on;
}
// Read potentiometer values
int pot_R_val = analogRead(POT_R);
int pot_G_val = analogRead(POT_G);
int pot_B_val = analogRead(POT_B);
int R_brightness = pot_R_val / 4;
int G_brightness = pot_G_val / 4;
int B_brightness = pot_B_val / 4;
Serial.print(" R : ");Serial.print(pot_R_val);
Serial.print(" G : ");Serial.print(pot_G_val);
Serial.print(" B : ");Serial.println(pot_B_val);
// Apply threshold
if (R_brightness < 20) { R_brightness = 0; }
if (G_brightness < 20) { G_brightness = 0; }
if (B_brightness < 20) { B_brightness = 0; }
// Update LED only if brightness or button state changes
if (currentMillis - previousMillis >= interval ||
R_brightness != prev_pot_R_val ||
G_brightness != prev_pot_G_val ||
B_brightness != prev_pot_B_val) {
previousMillis = currentMillis; // Update the time
digitalWrite(RELAY, led_on);
// Set the individual LED brightness
analogWrite(LED_R, led_on * 0.8 * R_brightness);
analogWrite(LED_G, led_on * 0.8 * G_brightness);
analogWrite(LED_B, led_on * 0.8 * B_brightness);
// Set the LED strip colors
for (int i = 0; i < STRIP_LED_NUM; i++) {
led[i].setRGB(strip_on * G_brightness, strip_on * B_brightness, strip_on * R_brightness);
// Swapping RGB channels to match the interpretation of the LED strip
}
FastLED.show();
// Store the current potentiometer values
prev_pot_R_val = R_brightness;
prev_pot_G_val = G_brightness;
prev_pot_B_val = B_brightness;
}
}
// Function to detect if a button is pressed
bool is_button_pressed(int button_no, bool &check_now, bool &check_before) {
check_now = !digitalRead(button_no);
if (check_now && !check_before) {
check_before = check_now;
return true;
} else {
check_before = check_now;
return false;
}
}
