Hellow Everyone

My project :

input : 5v mq3 sensor
5v flame sensor
5 v piezo disk vibr sensor
lm35 temp sensr


output : 2 channel 5v relay module
3 leds , 1 buzzer
2 -8bit Shift register IC74HC595 > 2 digit seven segment display
1 servo motor
so i need to ask i am powering all this from my arduino's VCC (5V) and 3.3v for zigbee
i havent connected all this together yet.. if i connect all this to the vcc .. will there be any power issues?
** arduino is powered from PC's USB**

You will need external power for the relay module and the servo. The rest can probably be powered by the Arduino. Current limit is 500 mA for USB, absolute maximum 40mA (20mA to be safe) each output not to exceed 200mA for the 328 chip.

Yes, there will most definitely be power issues. The first tasks are to consult each device's data sheet to determine the power requirements, and start researching how to control high-current devices like the MQ3 from the Arduino. For servos, budget at least 1 ampere of supply current for each straining servo.

okay only the relays and servo need separate power. right ?

others are fine ?

and what value of resistor shud i use for all these ..components .. to limit current ?

and what value of resistor shud i use for all these ..components .. to limit current ?

You don't.

You do not limit current, you provide it using a power supply of sufficient rating to provide the total.