Yodaman921's Project Log

Had an idea for a “secret” base entrance/exit. How many people try to search for someone’s base under their irrigation system? Button of course makes it obvious, but I wasn’t really trying to hide it. Push the button for a piston to open a passage that you drop down. Towards the bottom there’s water to slow your fall (I tested this with survival settings to ensure this won’t kill someone if made in survival). Once at the bottom, when you want to go up, press a button, TNT dispenses and detonates to create enough force to blast you up. At the same time repeaters send a signal up to reopen the piston at just the right time. Also, the base is far enough down to where people shouldn’t stumble upon it if they start digging where they shouldn’t.

Recently I’ve been messing around in Minecraft (Windows 10 Edition) and realized there’s a block I never used before, the Observer block. Once I learned that it was a block that emits a single pulse, I decided to try out an idea for a lava entrance to a base using the Observer block and some Dispensers.

In the past when working with Dispensers, a lever would have to be turned on to dispense something, off, and then back on to suck water/lava back up. That screws things up a lot if other things are hooked to the same lever. However, the Observer sends a pulse and after the pulse it’s considered off. So the dispenser is activated every time a lever is switched to where it could be “on = lava” and “off = no lava” or depending on how you set it up “on = no lava” and “off = lava”.

I started off with a basic just to ensure my mechanism was right before trying to do an entrance. I have a 3x3 grid of grass blocks on the bottom. Placed redstone on top of that, followed by observers and finally dispensers. A ring of grass blocks around the top to contain any lava, and a lever to activate.

After filling the dispensers with lava, a quick test shows that I’m on the right track. The observers sense the redstone turning on or off, and activate the Dispenser accordingly.

Now to make things a bit larger with a 5x5 base and try to make a secret entrance hidden below the lava.

I removed one of the side Observer/Dispenser combos and replaced it with a sticky piston and stone block, along with wiring it up.

At this point it should be noted that you need to be aware of when you put the lava in the dispensers initially. Since this design uses Observers, it results in a pulse, which equals either the lava is dispensed or the lava is sucked up. It does NOT mean “power = lava” and “no power = no lava”. So if lava is out when power is off, the piston will be retracted and your entrance will be flooded with lava!

Here’s what it looks like with it up and running:

Unfortunately, the lava is flowing toward where the entrance is, not very secretive... So lets add another Observer/Dispenser combo on top so that right above the entrance a lava block is spawned when it’s closed. To activate the Observer and thus the Dispenser, I extended my redstone to a sticky piston that lifts a block up to the Observer to set it off.  

Now lets test it out:

Perfect lava. However, the tops of the Observer and Dispenser aren’t that discrete, so let’s try hiding them a bit better.

Now there’s just a sliver of the Dispenser showing, but for the most part it’s pretty hidden. And when the lever is switched, our entry way is open to enter: