The ESP-01 module based on the ESP8266 is all the rage with IoT folks at the moment – and why not. For about 5 bucks, it can’t be beat on price for the features it offers.

Designed by Namnam in Vietnam, the ESP32 Modbus gateway is built to communicate with PLCs and industrial sensors over Modbus ...

The common form of the USB to Serial adapter is an FTDI breakout board. This requires drivers, though, and there is actually a simpler – and wireless – solution: the ESP8266 WiFi module.