The picture contains a module called the ESP-01 which a vendor called AI-thinker has put together that has an ESP8266 and other components which are needed for the ESP8266 to function. AI-thinker have several modules available from the ESP-01 up to the ESP-11 currently that all have different functionality. So what is it? well it has a 32bit CPU, integrated b/g/n WIFI, general purpose I/O pins, an analog to digital converter and a bunch of things that are not directly related to this project but for further information you can check out the community forum located here http://www.esp8266.com/wiki/doku.php
For my project I originally planned to use the Arduino platform instead of my usual preference for the Microchip PIC. The Arduino for those that do not know uses Atmel AVR microcontrollers. Both AVR and PIC do the same thing, they have very similar capabilities and I would not call either low end but more entry level microcontrollers that are embedded in so many products most people come into contact with every day and do not realize. The requirements for the brains of my project do not need a lot of heavy processing power but the bulk of what is needed will be required to move data from here to there and this is where the ESP8266 really comes into its own. At a cost of approximately $5 It simply cannot be beat, except for manually taking temperature measurements with a thrift store thermometer and logging that to a paper notebook. The circuit that I have in the previous photo that I put together in about an hour and cost just under $10. It has been happily taking measurements every minute and uploading them to a website for a couple of weeks without a glitch. I can go to that website (or even load a page stored locally on my laptop’s hard drive etc) and access the data to create a graph of my temperature and humidity.
This is a screen capture from my web browser that I cut and pasted. The data in the chart is dynamic on my private webpage, it updates every time data is sent from my sensor.
There has already been a lot of people designing circuit boards to use these modules but I could not find one to suit my needs, either the circuit boards had more than I required or would take too much effort to modify to suit my needs. I decided to have my own circuit board made that replicated the hardwired version in the picture above.