Being fairly new to command blocks in general, I am currently in need of a way to make a SINGLE command block check specified x,y,z coords. for "air", and, if AIR is detected at that coord. then send a redstone pulse to a different set of coordinates. This needs to be a SINGLE command block - no chaining!
This can REPEAT for as long as AIR is detected at that location (ie. as often as the command block is run (every tick?).
Can this be done in a single command block? Can it even be done at all?
For clarity, here is my objective: I have created a tree farm, where I ALREADY HAVE a way to "harvest" the fully-grown trees. I have also used a (fairly trivial) set of command blocks to allow a "vanilla" dispenser to "plant" saplings, instead of merely "dropping" them onto the ground. The saplings are planted DIRECTLY IN FRONT of each dispenser(s). Now what I require is a way to "trigger" each dispenser to re-plant a new sapling each time a resulting tree has been harvested. Once the fully-grown tree is cleared, the location is front of each dispenser will have NEITHER a sapling nor a "tree" (wood) block present there, thus, it is "empty", and I need a way to detect this situation, and "fire" a redstone pulse back at the pertinent dispenser!
BTW, I COULD simply re-trigger every dispenser at the SAME TIME using a redstone clock, and, if the spot in front was not "empty" for any specific dispenser, then a normal sapling "toss" would result, (ie. it would NOT get "planted" that time around); I could then absorb and return the sapling back to a "collector" inventory (eg. a chest), which would then re-distribute the un-planted saplings as required. I am simply wondering if a command block could be utilized in this particular way, is all!
Thanks for any help here!