Building a $10 ESP02 based ESP8266 Arduino WiFi Shield

I started a project of mine with a SparkFun ESP8266 WiFi shield.  After several frustrating weeks caused by a variety of issues, but mostly a bad U.fl connector (external antennas were unreliable), I gave up on that one, and decided to build my own, because I can.

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2016-09-04 by Unknown

Did you upload firmware to the ESP-02? What ESP firmware version works with the Sparkfun library?

2016-09-04 by Russell Graves

I’m running the AT firmware that shipped on my module. On the module I have handy:

AT version: 5 2015 16:27:16)
SDK version:1.1.1
Ai-Thinker Technology Co. Ltd.
Jun 23 2015 23:23:50

I probably should update the firmware, since I’ve got the serial interface to do it, but I haven’t. Any of the halfway recent AT firmwares should work fine with the SparkFun library.

2016-09-05 by Tobias M.

I have had better luck with GitHub - esp8266/Arduino: ESP8266 core for Arduino, than with using the ESP directly with it’s AT-firmware.

Using I2C to get the ESP8266 to talk to a regular AVR, everything worked very reliable and stable. Also you have much greater control over the network stuff (especially HTTP-request related stuff).

2016-09-05 by Russell Graves

Tobias -

I’ve seen that, but for what I’m doing the AT firmware seems to work fine. I haven’t had any issues with this shield.

Are you using the ESP as a wireless card with that library, or using it as a full Arduino? I need the additional analog IO pins for the project I’m working on.

2017-11-15 by ricg

any idea about range when using the antenna? is it better than the esp01?

2017-11-16 by Russell Graves

If you have a good antenna, certainly. I prefer directional antennas, which is why I wanted the ESP02.