Uploaded May 2014 | Updated September 2026, 1 week ago

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In this episode I show you how to build a wave spawning system. Sequential activation device is a glorified name for a wave spawner.

I used this device to create the wave system in my map Dungeon Arena 2. It can be used for any type of system that has multiple sequential outputs and a single input. Please let me know if you have any questions.

Bottom command block:
/setblock ~ ~1 ~ minecraft:air 0

Top command block:
/setblock $Input minecraft:command_block 0 replace {Command:"setblock $Output2 minecraft:redstone_block 0 destroy"}

Things to edit in the command blocks:
The "$Output2" should be changed to "$Output#" (# being the number of the output the command is on +1, unless it is the final output, in which case # is 1).

Signs:
Output# (# is the number of the different outputs)
Input

Output:
A redstone signal can be taken from any one of the sides of the air block in between the two command blocks. This signal is the output. It can activate whatever you need it to. In this case it activates a single command block, but you could have it activate a redstone device, or multiple command blocks.

Text based description:
When the input command block is activated it places a redstone block at one of the output locations. Once the redstone block gets placed, it activates a command block that replaces the input command block with a new command block. The new input command block has a setblock command in it that will place a redstone block at the next output location.

Links:
Sethbling's MCEdit Filter: sethbling.com/downloads/mcedit-filters/commandblocksigns

Dungeon Arena 2: minecraftmaps.com/game-maps/dungeon-arena/viewdownload

Pros/Cons:
Pros:
Infinitely expandable (within reason)
Multiplayer friendly (no scores that depend on players being logged in)
The device has memory (it remembers what item is next)
Compact (1 input command block and 2 command blocks per item)
Wireless (no redstone wires connected to each item)
Copy and paste set up (you only need to edit 1 number in each command block)

Cons:
All items must be placed in loaded chunks (can't set a block in an unloaded area)
MCEdit is needed (not really, but it makes things 10 times easier)

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▪Youtube Tutorial World Download: adf.ly/qcOod

Resource Pack: Experimental Faithful 32x32

Download Resource Pack: minecraftforum.net/topic/72747-faithful-32x32-pack-updatemore-17-rose-bush-pufferfish-17

Follow me on twitter: twitter.com/NateT_Bird

Thanks for watching!