Paired magical controllers, like 80s keyboards with a floating screen, used to aim and launch the crawlers' missile batteries.
Every one of the crawlers' missile batteries is fired by long-range magical trigger, all tied to a pair of controllers the system calls a Trollish Portable Control Room. They look like 80s-era keyboards with a magical screen floating above them and are fairly common in the dungeon — Carl notes that some seasons supposedly had gauntlet-style floors where crawlers had to reach a central control room and kill the trolls operating the traps.
For Bomo and Sledge, the crawlers had a former crawler modify the controllers to mimic the cretin-sized game controllers they had already made, since the two were familiar with those. Painted targets appear on the screen and the operators select specific missiles to launch at them, drawing from a stock of over 1,500 missiles of various kinds.
A pair of 80s-era keyboards with a magical screen hovering above them, modified down to cretin-sized game-controller form.
Fire-control interface for the crawler missile batteries at Area 52.