minecraft-java-editionminecraft-redstone
Is there a way to get a redstone signal when a player falls through a hole (right after he falls, not when he lands)?
Background: I created a bubble elevator and want a trapdoor for the other way around. When you want to go down, you open the trapdoor and fall, but the trapdoor would have to be closed again immediately after. I know I could make this work with tripwire, but I lack the space for that at the moment. If there is a better solution, I would be very glad for help.
Minecraftaddict's "Extreme Delay Redstone Timer" is the longest delay circuit I know of. (But I can see from the comments that you've already found it). However, directly using this circuit won't work with a light sensor output, since the output of a light sensor would be 10 minutes on and 10 minutes off.
The solution to this is to connect the output of your light sensor to a falling-edge and rising-edge monostable circuit that are OR'd together.
This is an image of a rising-edge trigger on the left, and a falling-edge trigger on the right. You would connect the A inputs together – to the output of your light trigger. When the A input is turned on, the Q output of the left circuit pulses. When the A output turns off, the Q output of the right circuit pulses. Because of this, you can connect the two Q output wires together (ORing them) to have an output that sends a signal whenever the light-sensor changes.
However, these circuits are designed to make a very short pulse. Because Minecraftaddict's delay circuit comes with a built-in pulse shortener, you will want to send a slightly longer signal to it. To do this, just add more repeaters to the edge triggers (add an extra repeater to when the current repeaters are). Leave the repeaters that should be on the first setting like that, but change the repeaters that should be on the second setting (according to the image) to the fourth setting.
You need to make a inverter (a NOT gate), just run the redstone up to a block then place a torch on the opposite side. When the redstone is off on the input it will make it on on the output
See the Minecaft wiki link above for diagrams for other styles of inverters.
Best Answer
This is how I solved it (for me personally, question is still not answered with this solution). Instead of hitting the trapdoor directly, I hit the button. Doesn't make much difference and I somehow like this approach even more.
For other people looking into this issue, I won't accept my own answer. If you come up with a more accurate approach to the question, feel free to post. I will give you credit for it.