The AI-Thinker manufacturer provides the ESP series with different models for different uses. In addition, different plates have emerged that incorporate some ESP module such as NodeMCU.
ESP-01
It is the most popular module although in many cases, it is not the most convenient. The price ranges from € 2 to € 4. At present it is not the most used, it has been removed by the ESP-12 of which I will speak later. Two digital GPIO pins are available to control sensors and actuators.
The Rx and Tx pins can also be used for this use if they are not used for communication through the serial port. It can be programmed through a serial / USB adapter or with the appropriate wiring, through Arduino. The connectors that come by default, do not allow to connect it to the protoboard.
This makes it difficult to prototype with this module. However, we can use L-shaped connectors to connect it to the prototyping board. We can use it as a stand-alone device or as a complement with Arduino.
ESP-05
It may be the simplest module in the entire range. It is meant to be a WiFi Shield for Arduino. Its price is around € 3. The arrangement of the pins allow us an easy connection with the protoboard. On the contrary it does not have any accessible GPIO port.
ESP-12
This module is becoming the company's flagship. It allows you to do many more things than the previous modules. Its price is around € 4. We have access to 11 GPIO ports of which one is analog with a resolution of 10-bit (1024 possible values). The sleep mode setting is very simple. This will allow us to save a lot of energy. On the contrary, the connection with the protoboard is not very friendly. We need to solder the pins or buy an adapter for € 0.20, although we must also solder. Perhaps this is the best option if we want to make it work autonomously.
ESP-201
It is the module preferred by the Makers to prototype. Its price is around € 6. In principle we can only access 11 GPIO ports but after some modifications, we could access a couple more of them. We can easily fit it into a protoboard and it allows the coupling of an external antenna to have more range.
NodeMCU
The NodeMCU is the most characteristic module of this type. Its price is around € 6. Unlike the other modules, it comes with everything you need to start working autonomously. It includes a serial / USB adapter and is powered through the microusb. It is based on the ESP-12 and the latest official version is 2. The most interesting thing about this module is that you can download a firmware that allows you to program in languages such as LUA, Python, Basic or JavaScript. Without a doubt, this module is the best option if we want to enter the world of ESP8266.
