user78212: I am trying to send AT commands to esp-01 through serial monitor I have uploaded a blank sketch to Arduino , whatever command I send to ESP I get reply ERROR.
After reconnecting esp-01 I got some garbage vales then ready.
Can anyone help me what I am doing wrong.
This is what I got on serial monitor

These are the connections I am using, I tried to use voltage divider but after using voltage divider, Esp's blue led turned on and nothing happened so I used just used the resistors in series between TX and TX of both devices

This is the voltage divider circuit I was using(that didn't worked)


user18934: The hardware serial, pins 1 and 2, are used by the Arduino to communicate to the USB adapter to your computer.  When you connect another device to them, it interferes with the communication between your computer and the Arduino.
The solution is to connect the ESP-01 to another set of pins and use the SoftwareSerial library to create a second serial port for it.  The code then needs to listen on both serial ports and move data between them.
Also, you need to use the voltage divider or you risk burning out the input pin.  To make the voltage divider, connect the Arduino output to the top of the divider and the ESP-01 to the middle.  You appear to have those reversed in your schematic.

78212: <p>I am trying to send AT commands to esp-01 through serial monitor I have uploaded a blank sketch to Arduino , whatever command I send to ESP I get reply ERROR.
After reconnecting esp-01 I got some garbage vales then ready.
Can anyone help me what I am doing wrong.
This is what I got on serial monitor
<a href="https://i.stack.imgur.com/rI64i.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rI64i.png" alt="this is what I am getting on serial monitor" /></a></p>
<p>These are the connections I am using, I tried to use voltage divider but after using voltage divider, Esp's blue led turned on and nothing happened so I used just used the resistors in series between TX and TX of both devices</p>
<p><a href="https://i.stack.imgur.com/rmqRk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rmqRk.png" alt="CONNECTIONS " /></a></p>
<p>This is the voltage divider circuit I was using(that didn't worked)</p>
<p><a href="https://i.stack.imgur.com/h81d9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/h81d9.png" alt="voltage divider circuit" /></a></p>
 18934: <p>The hardware serial, pins 1 and 2, are used by the Arduino to communicate to the USB adapter to your computer.  When you connect another device to them, it interferes with the communication between your computer and the Arduino.</p>
<p>The solution is to connect the ESP-01 to another set of pins and use the <code>SoftwareSerial</code> library to create a second serial port for it.  The code then needs to listen on both serial ports and move data between them.</p>
<p>Also, you need to use the voltage divider or you risk burning out the input pin.  To make the voltage divider, connect the Arduino output to the top of the divider and the ESP-01 to the middle.  You appear to have those reversed in your schematic.</p>
