user61268: This is my first project with any sort of development board and it has been a blast so far. 
I am running into some issues, however, while trying to send serial data from my Uno to a NodeMCU board. 
I have the following connections: 
Uno Rx to NMcu Tx
Uno Tx to NMcu Rx
Uno GND to NMcu GND 
microUSB from computer to power NMcu
usb from computer to power Uno
EDIT: after some suggestions, I have also tried the following. 
Uno DigitalPin 5 to NMcu D6
Uno DigitalPin 6 to NMcu D5
Uno GND to NMcu GND 
microUSB from computer to power NMcu
usb from computer to power Uno
With the following code:
// UNO sender Code
#include <SoftwareSerial.h>
SoftwareSerial toESP(0, 1); //Rx, Tx (also tried 5,6)

void setup()
{
  Serial.begin(115200);
  toESP.begin(9600);
}

void loop()
{
  Serial.println("sending");
  toESP.println("message from Nano");
  delay(1000);
}


// NodeMCU receiver code
#include <SoftwareSerial.h>
SoftwareSerial fromNano(3, 2); //Rx, Tx (also tried D5, D6)

void setup()
{
  Serial.begin(115200);
  fromNano.begin(9600);
}

void loop()
{
  if (fromNano.available())
  {
    char inChar = fromNano.read();
    Serial.print(inChar);
  }
  else {
    Serial.println("not available");
  }
  delay(2000);
}

I can pull up a serial monitor from both and see the UNO sending data (the TX led also blinks on the uno). 
The NodeMCU code never satisfies the fromNano.available condition. 
Is there anything I am overlooking that is causing this not to work? I've attached a picture of my connections as well. 

Any help is much appreciated. 

user13819: Arduino UNO is using pin 0 and pin 1 to have serial with USB serial Communication. You can not use them to softserial. Change softserial to other pins.  /Mikael

61268: <p>This is my first project with any sort of development board and it has been a blast so far. </p>

<p>I am running into some issues, however, while trying to send serial data from my Uno to a NodeMCU board. </p>

<p>I have the following connections: </p>

<p>Uno Rx to NMcu Tx</p>

<p>Uno Tx to NMcu Rx</p>

<p>Uno GND to NMcu GND </p>

<p>microUSB from computer to power NMcu</p>

<p>usb from computer to power Uno</p>

<p><strong>EDIT:</strong> after some suggestions, I have also tried the following. </p>

<p>Uno DigitalPin 5 to NMcu D6</p>

<p>Uno DigitalPin 6 to NMcu D5</p>

<p>Uno GND to NMcu GND </p>

<p>microUSB from computer to power NMcu</p>

<p>usb from computer to power Uno</p>

<p>With the following code:</p>

<pre><code>// UNO sender Code
#include &lt;SoftwareSerial.h&gt;
SoftwareSerial toESP(0, 1); //Rx, Tx (also tried 5,6)

void setup()
{
  Serial.begin(115200);
  toESP.begin(9600);
}

void loop()
{
  Serial.println("sending");
  toESP.println("message from Nano");
  delay(1000);
}
</code></pre>

<hr>

<pre><code>// NodeMCU receiver code
#include &lt;SoftwareSerial.h&gt;
SoftwareSerial fromNano(3, 2); //Rx, Tx (also tried D5, D6)

void setup()
{
  Serial.begin(115200);
  fromNano.begin(9600);
}

void loop()
{
  if (fromNano.available())
  {
    char inChar = fromNano.read();
    Serial.print(inChar);
  }
  else {
    Serial.println("not available");
  }
  delay(2000);
}
</code></pre>

<p>I can pull up a serial monitor from both and see the UNO sending data (the TX led also blinks on the uno). </p>

<p>The NodeMCU code never satisfies the <code>fromNano.available</code> condition. </p>

<p>Is there anything I am overlooking that is causing this not to work? I've attached a picture of my connections as well. </p>

<p><a href="https://i.stack.imgur.com/ChFWa.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ChFWa.jpg" alt="enter image description here"></a></p>

<p>Any help is much appreciated. </p>
 13819: <p>Arduino UNO is using pin 0 and pin 1 to have serial with USB serial Communication. You can not use them to softserial. Change softserial to other pins.  /Mikael</p>
