The Wi-Fi connects when the Arduino is powered by my computer and a serial console is connected, but not if I plug into an outlet.


It seems this is a power issue. I am powering the esp8266 from the Redboard 3.3v line that is only rated for 150mA. I will be switching to the 5v line with a 1A regulator.

I also switched to 9600 baud for communicating with the esp8266, added retries around all of esp8266 commands, and added reconnect logic in case the esp8266 reboots. With the changes, it works okay even with the underpowered 150mA line.

It's still a mystery to me why it works so well when connected to my Macbook.

  • Another thing to note is that you are likely to run into issues using SoftwareSerial at 115200. If you need to use SoftwareSerial, best to drop the baud rate. Depending on your firmware, the AT+IPR=9600 command should work. If you're getting garbage responses coming through from the ESP8266, this is the likely culprit.
    – Grant
    Commented Jan 12, 2016 at 22:40

1 Answer 1


It sounds like your power supply is inadequate to the task.

The ESP8266 is notoriously finicky about having a noise free power supply capable of delivering a lot of instantaneous power. If you are using a wallwart style supply it should promise at least 1A and more is better. Even though the actual use is more like 250 mA.

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