Error NodeMCU and arduinoIDE (MCU stopped working after soldering)

Solved
,
1

Hi, I have a problem with a card that I am assembling for a project, I have to control an RGB strip with a NODEMCU v2, as long as it was on the breadbord worked perfectly, the moment I go to solder the components on a millefori, the card issues this error even just by loading an ESP8266_STANDALONE.
Terminal:

ets Jan 8 2013,rst cause:2, boot mode:(1,6)

I already know that the restart is due to the gpo0, but it is disconnected!

this is the electric scheme:

schema_schemcorretto
schema_schemcorretto1236Ă—647 54.3 KB

The npn transistor are: bd221
(datasheet: search for a single component)

On the node mcu v2 these are the pins:
d0=gpio16 (Red Channel)
d1=gpio5 (Green Channel)
d2=gpio4 (Blue Channel)

Now the nodemcu v2 card also desoldering it and trying again to load the code (from disconnected) with arduino, it seems to no longer work as before.

With only the standard esp8266_standalone code from the terminal says:

from BAUDRATE=74880 →

ets Jan 8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 1384, room 16
tail 8
chksum 0x2d
csum 0x2d
v614f7c32
~ld
⸮⸮

from BAUDRATE=9600 →

d(⸮4⸮⸮[45] Connecting to Frattini_WIFI
$⸮%

I noticed that the operation led on the nodemcuv2 board emits a very weak light

Can someone tell me what it can be? Thank you so much!!

Mattia.

2

@frattomatti
nodemcu blown using NPN transistor !
you have to use optocoupleur

21-019400

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3

This is the Blynk forum, not electronics 101 forum :stuck_out_tongue: I don’t see a single Blynk related question here… and no “gonna use Blynk” doesn’t quite count yet :wink: )

PS @Blynk_Coeur Still, it is good advice :+1:

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4

@Gunner
I know very well that this is not a pure electronic forum, but I’m using the blynk library, and I wanted to ask you since you know how to use a nodemcu.

@Blynk_Coeur
The problem is that before welding the components together they were tested on a bredboard, and they were connected in the same way now, they worked perfectly.

5

That’s because you been lucky :wink:
If you don’t have an optocoupler at hand, add a resistor between the GPIO and the base and another between the cathode and the collector for each transistor. You may also want to look into MOSFETs

6

yes, it was before …
but you were lucky !
12v to 3.3v —> boum
never sure that the NPN emitter is not conductive with its base !
you have no protection for reverse current at power up,
no more protection in case of short circuit,
and no protection diode in case of polarity reversal
so better use optocoupleur

7

Blynk is an IoT GUI and library, not electronics 101 topics about “How I fried my MCU” (PS the Blynk library didn’t cause it :wink: )

But you have received the same answers about the need for proper isolation between high and low voltage devices, so we can call this non Blynk related topic resolved.

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