You are correct that a lot of rooms are using off the shelf Arduinos, often with buttons/reed switches/RFID tags for inputs, hooked up to a relay + maglock for

You are correct that a lot of rooms are using off the shelf Arduinos, often with buttons/reed switches/RFID tags for inputs, hooked up to a relay + maglock for the output. Some of the higher end rooms will pay a little extra for PLCs such as the ones from AutomationDirect. Another somewhat common controller are the BooBox controllers which come from the haunt industry. A lot of haunters got into escape rooms as a way to supplement income the rest of the year.