Which ESP8266 AT version supported by Library

Which ESP are you using (01, 03, 07, 12, 13 etc) and is there any reason you can’t remove the Uno from the project?

ESP as shield can be made to work but if you search the forum it can take a lot of setting up.

I used it for a short time but soon moved on to ESP standalone.

I am using ESP6288-01. I am not very familiar with ESP. Also the application I am looking after needs some I/Os and some LCD interface which I think easy with Arduino.


For an extra dollar you could have bought a decent ESP and sold your Uno for two dollars. Win, win.

Search the forum and you should be able to find a fix for the ESP01.

Good luck.


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Thanks. I actually had visited this link before. I have googled many times and tried almost all the things. Can any one tell what are the exact AT codes to test Blynk connectivity or which library is used to establish connection ?


The exact procedure is to use the correct example sketch from the Arduino IDE i.e ESP8266_Shield.ino

I already tried this but no luck. It will help if we have AT command in sequence which is used by Blynk library.


As pointed out earlier in this thread the files are plain text, take a look.

Common mistakes when using the shield:

Failing to read the comments in the sketch and amending it accordingly for the specific hardware.

Insufficient power, the ESP can be flashed from an Arduino but the ESP’s can’t run a sketch from the Arduino power.

Mixing up rx and tx pins.

Wrong baud rates set (3 baud rates to consider).

Trying to run a sketch with Serial Monitor open in shield mode.

Using wrong sketch.

Weak WiFi signal.

Poor circuit construction.


Below are some of the items that I tried but still not working. Could some one help? Please note that I am using Proteus for simulation. I can confirm that AT command works fine when tried from serial monitor.

  1. I tried Arduino Mega for simulation and connected TX1 and RX1 to ESP8266. When I looked at serial monitor on Tx0 and Rx0 it says failed to disable Echo.
  2. I tried to connect Arduino Uno in software serial mode and connected pins 10 and 9 to ESP8266. When I looked at serial monotor on pins 0 and 1, it says ‘failed to disable Echo.’ But strange thing is, it actually diable echo. So when I pass AT, it only says OK. Which means Echo has been disabled.
  3. I tried with CWMODE=3 but still no luck.

Could some one please help. I spent lot of time in googling and looking forums but no luck.


Could any one please help on above issues ?


Arduino’s and serial ports are not the best combination when you want a stable solution. I’m seeing this in the daily use of some of them. Also, when using software serial, as you indicate in case 2, it gets worse. You can try putting the ESP on the Hardware serial and use software serial and a USB-to-serial adapter to get debug info. That would probably be a better idea (I use Mega’s, so I always some hardware comports available for anything, really).

Furthermore, I wouldn’t trust simulators as far as I can throw them. Especially when it comes to serial traffic. I’d leave it alone, but that’s just me. Seeing the real thing work is the best simulation you can have :slight_smile:

And just to be sure, your ESP Tx is hooked up to your Arduino Rx? The Tx on the Arduino may require a resistor because the ESP has the 3v dataline and not 5v.

@bhavsak1 if you really must use the Uno buy one of these to go with it.

Not as flexible as an ESP shield but much easier to set up.

Hi just to confirm, I am little confused about Rx and Tx pines because different post in google shows different connections. As per my understanding it should be as below.

ESP8266 Arduino
Tx -------> Rx
Rx --------> Tx (thorugh resistor voltage devider to make it 3.3V data line for ESP)

Please confirm if this is correct. Now I am trying to connect Arduino ESP instead of simulator. But blue light of ESP is not blinking ( I suppose it is for Rx or Tx indication).

Or should it be as below.

ESP8266 Arduino
Tx -------> Tx (thorugh resistor voltage devider to make it 3.3V data line for ESP)
Rx --------> Rx


@bhavsak1 definitely “opposite” pins so rx to tx and vice versa. I think the confusion comes in when some boards and FTDI’s have labels showing what should be connected to them rather than what the actual pin is.

Voltage divider needs to be on the rx of the ESP as otherwise it will get 5V from the Arduino tx line.

Thanks Costas for quick reply. I have the same connection where Rx of ESP connected to Tx of Arduino with resistors as voltage divider and Tx of ESP connected to Rx of Arduino. But blue led on ESP is not blinking (I guess it is for Rx or Tx signal of ESP). Any idea on what might be a reason ?


The LED doesn’t flash all the time. It depends what the ESP is doing (connecting to AP, receiving a sketch etc).

Yes, it should not be flash all the time. But when I connected ESP using FTDI232 to my laptop USB using Arduino Serial monitor, whenever I apply any command the blue LED just blinks so I guess the same should happen when I connect to Arduino.


It depends what is in the Arduino sketch. You can set permanently ON, OFF or blink.

Hi, It finally worked :slight_smile:. I connected Tx of Arduino directly to ESP Rx (without resistor divider). I know that might be dangerous for ESP but not sure why it is not working with resistor divider.

Thanks @Costas and @Lichtsignaal for your help.

Just a question, currently I have connected Arduino to my laptop USB hence it is getting power from there. The program executes when I open Serial Monitor in Arduino IDE. Hence have a doubt if it will work if power Arduino from outside and disconnect from Laptop (Making Arduino stand alone). Not sure how the code will trigger (as currently looking for serial monitor to open).