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I wonder if a laptop USB port is enough or I have to use an external power supply if the NodeMCU under heavy load. Here is my list of sensors and port used.

3.3V
3.3V
D1 to D7
A0
GND    

Sensors: Turbidity sensor, Flow sensor, Temperature sensor, 4 led

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    That depends on how much current all that needs. We cannot know that. You didn't give us enough information. USB is limited to 500mA – chrisl Nov 14 at 2:24
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standard current you can draw from a usb port is 500 mili ampere with 5 volt(you may get even more but it is not recommended) . so if you want to calculate

sensors are very low current about 1~2 mA(but you must check out datasheet)

turbidity for example draws 30 mA

temperature ds1820 is 1 mA

flow is up 2 mA

the LEDs based on resistors series with them you normally up to 3 mA for each(1k series to 3.3 volt)

if you sum up all of them

30+1+2+4*3=45mA

but you should consider other consumers for example if you need 3.3 V you need a regulator such as ams1117 and it may waste some mili Ampere (not too much) and you certainly have a microprocessor and you should check data sheet but consider 100mA for that in worst case.

to count all of them the answer is YES

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Sensors don't usually require that much current and a usb port should be able to handle 4 leds and the MCU without a problem. If you are using an Apple laptop it will disable the usb port temporarily if you draw too much current from it. Some PC laptops probably do the same.

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