With that many LEDs you have to drive them with external drivers and use an external power supply.example: ULN2803 (8 drivers in one I.C.).Relays must have snubbing diodes across their coils to prevent Arduino damage.Relay should be driven with drivers also, ULN2803 will do this.
Good for you for learning Fritzing.
Do i have to connect pins 1 to 8 from ULN2803 only to PWM pins on Arduino? Or it will work the same with any other digital pins? Because even if i use the MEGA, i only have 12 PWM pins.
Unused pins on the ULN2803 can be left floating.The 2803 can be used on any Arduino O/P not just PWM.
Buy some extra 2803s for future projects.
And i don't need to use any resistors between Arduino's Digital pins and pins 1 to 8 from ULN2803, right? Only between ULN2803's output pins and the LEDs.
You have GND going to the Anodes of the LEDS, you want +5V to the Anodes.
Your 2803 to the relays should be turned 180'
You are showing the Black wire (GND) of the external power supply going to the LEDs, you should have the Red wire (+5V) going to them.+5V(red wire)----LEDs----Resistors----2803 o/p
Isn't supposed to go like this: I send the "HIGH" signal from the Arduino digital pin, then it goes to the ULN2803 pin (1 to 8 ), then the 2803 opens the current flow from the 5V (External Power Supply) to the LEDs (through the resistors), and finally the GND wire closes the circuit?
Can you make a quick scheme so i can go on from there?
So current flows from external power supply: +5V through the LED through the resistor through the 2803 o/p to common GND.