user60666: 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

user48909: 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

60666: <p>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.</p>

<pre><code>3.3V
3.3V
D1 to D7
A0
GND    

</code></pre>

<p>Sensors: Turbidity sensor, Flow sensor, Temperature sensor, 4 led</p>
 48909: <p>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</p>

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

<p><a href="http://www.farnell.com/datasheets/1770074.pdf" rel="nofollow noreferrer">turbidity</a> for example draws 30 mA </p>

<p>temperature ds1820 is 1 mA</p>

<p>flow is up 2 mA</p>

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

<p>if you sum up all of them </p>

<p>30+1+2+4*3=45mA</p>

<p>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.</p>

<p>to count all of them the answer is YES</p>
