ESP8266-01 is the name of a great little WiFi module for remote control or sensing.
Just connect an ESP8266-01 module to an Arduino Pro Mino and you have a really tiny WiFi network connection. A company called Espressif, based in Shanghai, makes a range of wireless and Bluetooth devices. These contain a complete “system on a chip”. The ESP8266-01 is at the low end of a number of modules which package the Espressif chips. It has been selling on E-Bay since 2014 and are currently priced at around $2. In addition to the Espressif “system on chip”, these modules contain a UART (for serial communications) and a 2.4 GHz WiFi transceiver and antenna.
There are literally tons of things that IoT (Internet of Things) enthusiasts do with these modules. Projects include remote sensing, home security and remote control. In my case, I will use the ESP8266-01 with an Arduino to remote control an external magnetic loop antenna. The module has good range. The antenna will actually show up as device on my home network. A web search will turn up thousands of articles and videos about projects using this module and its siblings.
ESP8266-01 Learning Curve
There is quite a learning curve when trying to use the ESP8266-01. The biggest challenge relates to inconsistencies in the various versions of firmware used by these devices. Most of the modules are made by another Chinese company called AI-Thinker. The firmware they provide appears to be pretty flaky and inconsistent in performance. Most users quickly try to flash new firmware, more recent versions. You can find these on the various Espressif user sites.
After trying various versions, I settled on a June 2015 AT Command Version 0.25 (SDK Version 1.1.2). You can find it here. While it is not the latest firmware version, it seems to be the best of the bunch I have tried: very stable and easy to document commands and responses.
One final note. The ESP8266-01 needs a 3.3 volt power supply and connections. Although it has a very effective sleep mode, in normal operation it draw lots of current.
Ok, so now that I have good firmware installed, it’s time to move on to integrating this module into my loop antenna control system.