BUD switches (short for Block Update Detector) can be triggered without levers, buttons, tripwires, or any other traditional switches. Instead, they're triggered by changes in block status. That is, placing a block, destroying a block, hoeing grass, clearing snow, etc.
These switches can be difficult to understand because they utilize a game glitch related to when blocks "update" to accommodate their changing environment.
There are myriad ways to make BUD switches, but I'll cover what I consider to be the two best designs, one that functions like a lever, with permanent on/off states:
And one that functions like a button, which resets itself after each triggering:
BUD switches can even be strung together to create an entire line of them:
So swing by our server mc.wonderhowto.com this Saturday, August 11th at 12:01 pm PST (3:01 pm EST) to participate in the workshop.
Our workshops are best when you log onto our Teamspeak server at ts.wonderhowto.com, so that you can listen in to all the chatter and helpful tips. Workshops are always both fun and informative, so drop by and check it out!
I look forward to seeing you there!