As soon as you get an ESP8266 WiFi module, the first thing you want to do is check if it’s working or not. The first thing you need to do to check it is to power it up either from a 3.3v source or a 5v source. Remember that the ESP Module is 3.3v compatible only so you have to be sure to make appropriate circuit for powering it up. Also remember that RX and TX pins of the module are also 3.3v compatible so better be careful when connecting to a TTL micro controller (check out this page for 3.3v compatible circuit and this page to make ESP module 5v compatible)
Next you want to connect it up to a computer to be able to send AT commands and see the response from the WiFi Module. AT Commands are used to configure the ESP module, set the IP addresses, change modes, create TCP/IP client / server, send data, receive data and much more. Basic introduction to some of the basic AT commands based communication is discussed here
To connect ESP module with a computer we use PL2303 USB to TTL Interface, it is a small USB to TTL serial tool, using the PL2303 chip. You can use it to connect some serial device to your PC via USB port.
- Module Type : AdapterBoard
- Size : 4.6 x 1.5 x 1.1cm
- Operation Level : Digital 5V
- Power Supply : External 5V
Following image shows how to connect 5V compatible ESP adaptor to PL2303 USB to TTL Interface
Following image shows how to connect a 3.3v compatible ESP adaptor to PL2303 USB to TTL Interface
Install the driver for PL2303 if you haven’t already and that’s it!!! you are ready to communicate with your WiFi Module.
Note: PL2303 is not the only USB to TTL converter in the world, check out the following alternates, compare prices to make a decision when buying