I believe this is the first working suspended retractable bridge of its kind.
It is a bridge that spans 4 blocks, and has two spaces underneath (so you can actually walk/swim under it).
Bridge Retracted
Bridge Extended
Side view
As you can see in this picture, there are 2 blocks space below the bridge (1 is used for the moat)
Shaft view
This piston shaft below the moat raises sand to the bridge's level, after which the bridge is extended,
and the sand is inserted into the other side (the sand is necessary to push the bridge back)
Control logic
This circuit raises the stack of pistons, and retracts them again in the correct order: !C !B !A B !B
Notes
- This took about 6 hours to design and build.
- This thing is pretty smooth. It somehow reminds me of the mechanical action when inserting/removing a VHS tape from the VCR (I probably just gave away my age).
- I could have just made a bridge using just the piston stack, but then it would not be a proper suspended bridge, you would not have material choice, and it'd just look plain ugly.
- It is entirely possible to make it 4 blocks wide, too. But it'll need a lot more space underground.
I have not gotten around making the buttons toggle the bridge though, it's just set on one side, reset on the other side.
Also, another improvement would be to not retract the top sand-piston until the bridge is retracting again, so the moat won't have a 2x3 pit in it.
Wow. This is excellent. Great job! I would never have thought of something like this :tongue.gif:
Now, to analyze it and figure out how in the world it does this awesomeness...
I've been trying to think how to make a bridge like this retract. Too bad it doesn't seem possible without the sand, but it looks like a good solution.
I tried optimising the sand lifting system, and it's somewhat smaller than it was, and the delay before the bridge forming has been decreased. However, neither are optimal :tongue.gif: I also deliberately introduced a 1 tick delay to the activation of the bridge protruding pistons, just to improve reliability.
Thanks :smile.gif: I've also got rid of the 3x2 hole, but I don't really think that warrants a second upload. Ironically, it actually simplified the system
Hehe it's just like my first design. Then I had to redesign it after seeing you can line up sand/gravel and use multiple pistons to push it out at a speed fast enough that it literally defies gravity extending across air. Then once it all pushes out it'll fall and then can be recycled back into storage to be used again. Removes the need for all those pistons on the bottom that push the sand up plus it means you can have your bridge much higher off the ground and even keep it completely concealed.
Hehe it's just like my first design. Then I had to redesign it after seeing you can line up sand/gravel and use multiple pistons to push it out at a speed fast enough that it literally defies gravity extending across air. Then once it all pushes out it'll fall and then can be recycled back into storage to be used again. Removes the need for all those pistons on the bottom that push the sand up plus it means you can have your bridge much higher off the ground and even keep it completely concealed.
Awesome! I thought about a bridge build by lava and water (cobblestone) and destroyed with TNT. only that you need bedrock. (obsidian CAN be destroyed!)
Please, guys, reupload the save file or a schematic. This is awesome thing!
Holy thread necro batman!
Anyway, science advanced a bit past this thing already. I have an even better bridge these days that's smaller, faster, and can bridge any height. (still only spans 4 blocks though).
Hey, so I'm sure this is a long shot, but I am also desperately trying to figure out a retractable bridge just like this. After extensively searching the web this is the only thing I could find and its like from 5 years ago. First off, ingenious human who figured this out, you are a god among minecrafter and take heart that either I am bad a looking or no one else has figured this out in five years. Second off, I would absolutely love to understand this better with either a world file or video or even photos and steps, thank you so much for your brain, it is an asset to minecraft world!
As this still seems to be the only bridge design of its kind on the web and the world download is broken, I took the liberty of reverse-engineering Entity's design from the pictures and tweaking it to work in 1.12.
I believe this is the first working suspended retractable bridge of its kind.
It is a bridge that spans 4 blocks, and has two spaces underneath (so you can actually walk/swim under it).
Bridge Retracted
Bridge Extended
Side view
As you can see in this picture, there are 2 blocks space below the bridge (1 is used for the moat)
Shaft view
This piston shaft below the moat raises sand to the bridge's level, after which the bridge is extended,
and the sand is inserted into the other side (the sand is necessary to push the bridge back)
Control logic
This circuit raises the stack of pistons, and retracts them again in the correct order: !C !B !A B !B
Notes
- This took about 6 hours to design and build.
- This thing is pretty smooth. It somehow reminds me of the mechanical action when inserting/removing a VHS tape from the VCR (I probably just gave away my age).
- I could have just made a bridge using just the piston stack, but then it would not be a proper suspended bridge, you would not have material choice, and it'd just look plain ugly.
- It is entirely possible to make it 4 blocks wide, too. But it'll need a lot more space underground.
World file
Since this is far too complicated to make building steps for, here's the world file:
http://www.mediafire.com/?c3guvtdppj2n73t
I have not gotten around making the buttons toggle the bridge though, it's just set on one side, reset on the other side.
Also, another improvement would be to not retract the top sand-piston until the bridge is retracting again, so the moat won't have a 2x3 pit in it.
Anyway, hope you like it.
Now, to analyze it and figure out how in the world it does this awesomeness...
Good job.
Its the most compact I have ever seen.
Clever :smile.gif: It's really fast now
Edit: nice catch on the pulse limiter too.
Please upload! :tongue.gif:
*edit* lol necro post.
can you post a save with this bridge in it?
Holy thread necro batman!
Anyway, science advanced a bit past this thing already. I have an even better bridge these days that's smaller, faster, and can bridge any height. (still only spans 4 blocks though).
Download world file
Trying to find a suspended retractable bridge design is insanely hard - and I'm failing at my own design.
The world file would be awesome...or if anyone has a new working model?
Hey, so I'm sure this is a long shot, but I am also desperately trying to figure out a retractable bridge just like this. After extensively searching the web this is the only thing I could find and its like from 5 years ago. First off, ingenious human who figured this out, you are a god among minecrafter and take heart that either I am bad a looking or no one else has figured this out in five years. Second off, I would absolutely love to understand this better with either a world file or video or even photos and steps, thank you so much for your brain, it is an asset to minecraft world!
As this still seems to be the only bridge design of its kind on the web and the world download is broken, I took the liberty of reverse-engineering Entity's design from the pictures and tweaking it to work in 1.12.
So that the next person who stumbles upon this thread looking for a drawbridge doesn't have to suffer like I did, I've made an album with pictures of the device from various angles, as well as the adjustments I had to make to get it working.
It's no tutorial, but it should be enough information to replicate Entity's design.