We published Arduino library for HI-LINK RM04 WiFi module with Aruino Uno board. Uno board provides just one UART for PC communication, so we used AltSoftSerial library to use software serial port to communicate with RM04 module. Because of the limited memory of Uno, the library only provides web client functionality. Even scan function was removed from the original driver.
Original driver from Chunlinhan : https://github.com/chunlinhan/WiFiRM04
Modified smaller driver : https://github.com/chiknhed/small_wifi_rm04