Communicating b/t Arduino Uno and ESP8266 ESP01

Projects General Guidance
1

I'm pretty new to this whole thing, and have run into an issue with setting up serial communication between an Arduino Uno board and an ESP8266 module. Everything's hooked up and running, but what I would expect to happen doesn't seem to be working -- and I'm not sure if it's something that I'm doing wrong or something that just doesn't work like I'd think.

So...I've set up the ESP8266 so that it can fire up a server and respond to HTTP requests through a simple tutorial. That works great. What I thought I could do was simply add a serial reader to the ESP8266 and a serial writer to the Arduino (and vice-versa) so that a switch hooked up to the Arduino can trigger a response to the ESP8266.

So, on the Arduino I have a simple loop:

void loop() {
  if (Serial) { 
    Serial.println("Testing");
    delay(1000);
  }
}

And on the ESP8266, I've got a reader in the loop:

void loop() {
  // send data only when you receive data:
  if (Serial.available() > 0) {
          // read the incoming byte:
          incomingByte = Serial.read();

          // say what you got:
          Serial.print("I received: ");
          Serial.println(incomingByte, DEC);
  } else {
    Serial.println("No data sent.");
    delay(5000);
  }
  ...

The Serial.begin is in the setup of the ESP8266, but not in the Arduino code (when I try to use Serial.begin from the Arduino, the ESP8266 does't start up properly).

So, having said all of that, here's what I'm shooting for:

I want to have a switch that, when its state is changed, triggers the ESP8266 to post to a website. Seems easy in theory, but in practice this is much more complicated that I thought it would be.

Any suggestions would be greatly appreciated.

3

Cool, so if I move the Serial.begin to the Arduino, do I still need the Serial.begin on the ESP as well?

5

I have read a lot of the reference material; when I have a Serial.begin on the Arduino, I only the Arduino output in the Serial monitor; when I remove that, I see the EPS output. But there doesn't seem to be any actual communication going on between the two...

7

Aha...that's what I was missing. Thanks, that makes perfect sense.

8

GPIO2 of the ESP8266 is its TX1, meant for exactly this situation: the regular RX0/TX0 (GPIO 1 and 3) are in use, but TX1 can still send data to a serial terminal for debugging.