https://www.clasohlson.com

RemoteCapture.ino by Øyvind Haga: https://www.instructables.com/id/Control-CoTech-Remote-Switch-With-Arduino-433Mhz/

1. Load up RemoteCapture.ino and plug a 433.92MHz receiver to digital pin 2.
2. Open up Tools -> Serial Monitor in Arduino IDE and start pressing buttons from your original remotes. Note that each button sends 4 different codes and at least 2 of them are needed.
3. Copy paste the 24 bit commands to COTech.ino for sendCOTechCommand().

1. Set the plug into pairing mode by holding down its power button until the LED starts blinking.
2. Send a command, eg. "sendCOTechCommand(SWITCH_A_ON);", which stops the pairing mode.
3. Now you can control the plug, e.g. sendCOTechCommand(SWITCH_A_ON); (or SWITCH_A_OFF).