Pradeep Singh | 5th April 2016
NodeMCU ESP12 Dev Kit V1.0 Pin Definition:
While writing GPIO code on NodeMCU, you can’t address them with actual GPIO Pin Numbers. There are different I/O Index numbers assigned to each GPIO Pin which is used for GPIO Pin addressing. Refer following table to check I/O Index of NodeMCU GPIO Pins –
| GPIO Pin | I/O Index Number |
| GPIO0 | 3 |
| GPIO1 | 10 |
| GPIO2 | 4 |
| GPIO3 | 9 |
| GPIO4 | 2 |
| GPIO5 | 1 |
| GPIO6 | N/A |
| GPIO7 | N/A |
| GPIO8 | N/A |
| GPIO9 | 11 |
| GPIO10 | 12 |
| GPIO11 | N/A |
| GPIO12 | 6 |
| GPIO13 | 7 |
| GPIO14 | 5 |
| GPIO15 | 8 |
| GPIO16 | 0 |
IoT Bytes 
Why is there no +5V DC supply pin on the NodeMCU (Amica version)?
I have an application using DC motors where the L298N Dual H-Bridge chip has two +5V pins (Vss and Vs). The Vs is to be an external supply to power the motors, and Vss is the logic supply voltage. This is usually a +5V DC supply from the MCU board.
My question: Is there a point on the NodeMCU board that I can tap +5V to supply my L298N chip?
The LoLin NodeMCU does have a +5V DC supply pin called “VU” (short for VUSB, I guess), but the LoLin board is to wide for my application (needs to be narrow enough to use on a MB-102 breadboard with at least one available pin hole in the breadboard for each pin on the NodeMCU Board.
Looking into the matter some more, now I realize where a pretty good place to tap +5V from the NodeMCU board. There’s the AMS1117 voltage regulator chip that regulates the +5V from the USB cable/connector. The chip has 3 sizable pins and a heatsink. The three pins are rather big, especialyy as compared to the other micro-miniture SMD chip pins and solder points on the NodeMCU board. The Input pin on the AMS1117 should be +5V, so I’m planning to solder a wire onto it and use the wire to jumper the +5V power over to the Vss pin on the L298N chip.
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A 5 V version is not in your future.
In the meantime ….. https://www.google.com/search?q=3.3+to+5v+level+shifter&rlz=1C1CHFX_enUS754US754&oq=3.3+to+5v&aqs=chrome.1.69i57j0l5.7349j0j7&sourceid=chrome&ie=UTF-8
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The nodemcu have a 3.3 V operation mode, the Vin pin is able to manage and stepdown a 9V input at most.
If you need 5 volts for the DC motors, you will need add a 5 volt power supply and send the signals trough a Logic Level Shifter, https://www.sparkfun.com/products/12009
or maybe a optocoupler or relay to separate both lines.
https://www.sparkfun.com/products/13815
https://www.sparkfun.com/products/9118
I’m not related with sparkfun, but they have so many modules and breadboards… there you can find almost anything.
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could i use python for doing programming in nodemcu esp8266 for sensors.
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Yes, you can use MicroPython on ESP8266. You can start with following Doc page –
https://docs.micropython.org/en/latest/esp8266/esp8266/tutorial/intro.html
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It’s really a cool and useful piece of info. I’m glad that you shared this helpful information with us.
Please keep us up to date like this. Thanks for sharing.
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For the NodeMCU Amica board Vin is 5v. All other VCC pins are 3.3v
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