Connect to Blynk without usb cable

Need Help With My Project
1

  1. For communication between arduino & blynk, we need USB data cable.

  2. So for communication between esp8266 attached to arduino uno & blynk, how does the communication occur?

  3. Do I still need USB cable of arduino connected after program is flashed?

  4. Should I select ESP8266 in Blynk Project?

I am getting the error of “Echo Failed”. I want to use software Serial. I am using pins 10,11 for TX & RX Please help

2

@iot1 you just need to provide power to the Arduino and ESP once you have them configured, USB to PC is not required.

If you are doing Arduino with ESP shield DO NOT select ESP8266 in the project, select the model of Arduino that you are using.

Echo Failed is a nightmare, spend a few hours searching that time on this site and try the solutions offered.

To make life easy forget the Arduino and stick with ESP’s.

3

“1. For communication between arduino & blynk, we need USB data cable.”

the first statement is not true / too vague. what do you mean by “blynk”?

actually, you need the usb cable to provide power or to use serial monitor on pc.

4

My Blynk project was not detecting arduino, so when i entered ‘blynk-ser.bat -c COM8’ in command prompt, blynk detected arduino. But when I removed the cable, again it went offline.

5

Thanks for your reply. I am simultaneously reading all the topics in the forum. I tried -

  1. changing baud rate
  2. changed serial pins
  3. flashed esp firmware
  4. separate power supply for esp
    But all in vain.
6

ok. Now am getting ‘wifi connected’.

Can you help me with blynk part? Am getting ‘device offline’ message on blynk app. When creating the project, I chose

  1. Hardware Model = Arduino Uno
  2. Connection type = Wifi
7

Can you help me with blynk part? Am getting ‘device offline’ message on blynk app. When creating the project, I chose

  1. Hardware Model = Arduino Uno
  2. Connection type = Wifi
8

@iot1 post your formatted sketch and presumably with the very limited Uno you don’t have access to Serial Monitor as the TX / RX pins are connected to the ESP.

9

@iot1 Just to clarify.

USB-link and WiFi are two completely different methods of connecting your Arduino to Blynk.

The Arduino can connect to Blynk via the USB and the blynk-ser.bat file, but the Command Window must stay open and UNO must stay plugged in to USB, in order to maintain the connection.

If using the ESP to connect the UNO, you only need the USB for power and programming… and once programmed you can switch to external power (battery or AC adapter).

As you have noticed, Arduino/ESP mergers get much tricker from there. but you seem to be on the correct path toward getting that to work.

As Costas mentions, you can try to connect to the ESP via the UNOs RX/0 & TX/1 pins. No SoftSerial library or commands, just treat as normal serial and NO USB connection - except as power only - but probably even better to use external power (And unplug the ESP when programming the UNO).

Or connect to the ESP via SoftSerial Library with the pins used typically being RX/10 & TX/11, this way you should be able to also use the USB serial monitor.