Can we use the vin pin of the lolin v3 nodeMCU as a 5V supply. If yes, i checked mine with a multimeter. At max, it gives a voltage of 2V. Is my pin blown out? Also, can use the VU pin as a 5V supply? Will using it cause any problems to my laptop's USB port? Can somebody help me out?

 

It seems unlikely that you can use an input pin as a supply pin. What are you thinking, and why is this important to you?

 

It seems unlikely that you can use an input pin as a supply pin. What are you thinking, and why is this important to you?

In the previous versions of the board, the vin pin could be used as a 5V output pin for sensor interface when powered by USB. I read online that the v3 does not have this capability. So I'm confirming if it is correct or not.
In application, i need to drive a 5v relay using the v3 board.

 

In the previous versions of the board, the vin pin could be used as a 5V output pin for sensor interface when powered by USB. I read online that the v3 does not have this capability. So I'm confirming if it is correct or not.
In application, i need to drive a 5v relay using the v3 board.

If the v3 (version 3 as opposed to 3 Volts?) can still be powered by USB, then maybe. USB has a 5V power spec for the cable. AFAIK there is no option to run USB at any voltage less than +5V DC. How about links to datasheets for the board and chips. At this point we are only guessing.

 

There is no official datasheet released by Lolin for their nodemcu version 3. I did find a few websites that explained the differences between this and the previous version 2.
https://arduino.stackexchange.com/questions/75645/vin-vu-pins-of-nodemcu-v3
https://www.theengineeringprojects.com/2018/10/introduction-to-nodemcu-v3.html

 

There is no official datasheet released by Lolin for their nodemcu version 3. I did find a few websites that explained the differences between this and the previous version 2.
https://arduino.stackexchange.com/questions/75645/vin-vu-pins-of-nodemcu-v3
https://www.theengineeringprojects.com/2018/10/introduction-to-nodemcu-v3.html

That makes it really hard to answer your question.

 

Can we use the vin pin of the lolin v3 nodeMCU as a 5V supply. If yes, i checked mine with a multimeter. At max, it gives a voltage of 2V. Is my pin blown out? Also, can use the VU pin as a 5V supply? Will using it cause any problems to my laptop's USB port? Can somebody help me out?

vin in your board is connected to a buck regulator AMS1117 that configured to drop voltage in a certain ratio of voltage. you need a 9v/12v battery to power via VIN else improvise the usb connector that is already provided