Help with Wemos D1 mini!

Need Help With My Project
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1

I am trying to make my first arduino simple project based on the directions of this video for a gift to my fiancee https://www.youtube.com/watch?v=duiAbLsXZSE&ab_channel=Breaks%27n%27Makes

You may watch it so you can understand better.

It uses the app Blynk.

I follow his directions exactly but I made one change: I use a WS2811 led strip with a 12V-1A power supply so I power the LED strip from the power supply by soldering it on the step down converter’s inputs.

Long story short, I fried 2 Wemos. Maybe it was my fault because I accidentally put wrong wire to the wrong input. I dont remember tbh.

The connections are fine.

Here was the circuit:

Led lamp (1)
Led lamp (1)3000×1350 420 KB

Here is the code:

#include <SPI.h>
#include <BlynkSimpleEsp8266.h>
#include <ESP8266WiFi.h>
#include <Stepper.h>

#define PIN D2
#define NUMPIXELS 60
#define BLYNK_PRINT Serial

int motorSpeed; 
int motorDirection; 

const int stepsPerRevolution = 4096; 

BlynkTimer timer; 
Stepper myStepper(stepsPerRevolution, 14, 12, 13, 15); 
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

void stepperControl() {
  if (motorSpeed > 0) {
    if (motorDirection == 0) {  // Rotate Clockwise
      myStepper.step(stepsPerRevolution / 50);
    } else {  // Rotate CounterClockwise
      myStepper.step(-stepsPerRevolution / 50);
    }
  }
}

void setup()
{
  Serial.begin(9600);
  timer.setInterval(1, stepperControl);
  Blynk.begin("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX", "XXXXXXXXXXXXXXXXX", "XXXXXXXXXXXXXX");
  pixels.begin();
  pixels.setBrightness(55);
}

void loop()
{
  Blynk.run();
  timer.run();
}



BLYNK_WRITE(V0)
{
  motorSpeed = param.asInt();
  myStepper.setSpeed(motorSpeed);
}


BLYNK_WRITE(V2)
{

  int R = param[0].asInt();
  int G = param[1].asInt();
  int B = param[2].asInt();
  Serial.println(R);
  Serial.println(G);
  Serial.println(B);
  for (int i = 0; i < NUMPIXELS; i++) {

    pixels.setPixelColor(i, pixels.Color(R, G, B));

    pixels.show();
  }
}

I gave a shot at it again.

Removed the led strip from the equation, to simplify things.
Bought a new same Wemos.

  1. The sketch uploads successfully again.
  2. Voltage measurements seem fine before the wemos is connected.
  3. When Wemos is connected to the circuit, Voltage across the 5V input of the Wemos as long as positive output of the step down converter becomes about 3.4V (!!!). Even though before wemos, the voltage is at 5V!
  4. Stepper driver lights come on except the 4th one. Stepper motor not rotating.

Note: When connected from the USB, the lights of the stepper driver dont even light on.
The connections of the inputs of the stepper driver are correct since I copied them from the tutorial.
Also, the Wemos gets kind of hot.

Here is another video of a failed attempt:

https://youtu.be/URC1zY3y0tY

At my wit’s end.
Help.

2

Please edit your post and add triple backticks ( ``` ) before and after your whole sketch.

3

If you disconnect the wire from pin D2 and measure the voltage between that wire (the middle pin of the LED strip) and GND, what do you get?

Pete.

4

After many tests and searching, just seems that the issue exists even without the presence of the LED strip. As I mentioned, I removed the led strip from the equation, to simplify things.
When Wemos is connected to the circuit, Voltage across the 5V input of the Wemos as long as positive output of the step down converter becomes about 3.4V (!!!). Even though before wemos, the voltage is at 5V!

5

My guess is that you’ve killed another Wemos.

I suspect that the LED strip is outputting a voltage on it’s middle pin, and that this has killed the Wemos.
Try the voltmeter test I suggested earlier to confirm this.

Pete.

6

No. Because wemos runs fine at the USB with another example.
Also, just realised voltage drops at 3.4V even without the wemos and only the stepper driver connected to the step down converter!