Arqade is a question and answer site for passionate videogamers on all platforms. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm working on a project that requires a fairly long delay. I found the "Rotary hopper clock" on Minecraft 101, and I do like the compact design it has to it. However I'm not entirely sure how it works, and the article I found doesn't go very in-depth on it. I'm not really new to Redstone, but I haven't really gotten too far into it until now.

So, how exactly does it work (I'm not even sure where the output is), and how am I supposed to use it?

Here is a picture of it from the article: Rotary hopper clock

share|improve this question
What delay length do you need? – It'sNotALie. Sep 9 '13 at 21:47
@It'sNotALie. I need it to be 30 to 45 seconds. I know that's not "long" in real time, but for setting delays (for me) it kind of is. – user47129 Sep 9 '13 at 21:52
Is "silent" a design specification? If not, there's a much smaller and easier to configure design I know of. Though I'm sure it wouldn't be difficult to configure this design. – Unionhawk Sep 9 '13 at 22:00
Hmm, a normal hopper timer could do that sort of delay. Look it up, I would answer but I'm on mobile. – It'sNotALie. Sep 9 '13 at 22:01
@Unionhawk I'd prefer it if the timer didn't make too much noise, so I'd like it to be quiet/silent. I'm interested in the smaller (and easier to configure) design. Could you give a link or name to it? – user47129 Sep 9 '13 at 22:12
up vote 7 down vote accepted

The primary design I use for a configurable timer (as of Minecraft 1.5) is Etho's hopper clock.

Etho's hopper timer

(there's no hidden redstone and both pistons are sticky, and the hoppers are facing into each other)

Unfortunately, unlike the other design, this one is not completely silent; there's a piston pulse every cycle of the timer. But the same mathematical principles apply to this design too.

Hoppers transfer items at a rate of 0.4 seconds per item, which means 0.4 seconds per item per half-cycle (0.4 seconds with the redstone block in one position, 0.4 seconds in the other). So with Etho's design, the formula for the number of items is 0.8 * items = seconds. So if you want a pulse every 8 seconds, you need 10 items.

The design you show runs on the same principles, but with a repeater for each part-cycle, adding 1 redstone tick (0.1 second) per part-cycle. So the formula for this one is 1.6 * items + 0.4 seconds per full-cycle.

So assume only one hopper output is "on", and you want a signal of any length every 30 seconds. Doing the math gives a magic number of 18,5 items, so we'll use 19 and call it close enough. I did some in-game testing, and came up with 30 seconds, and it comes out to being about 15 on, 15 off.

The important bits:

  • With the design you show, (4 hoppers in a circle) you can calculate the number of items needed by (1.6 * items) + 0.4 = seconds
  • With Etho's design, shown above, you can calculate the number of items needed by (0.8 * items = seconds
share|improve this answer
Um, should the hopper be doing anything with the items inside of it? I built everything as you did, and the blocks (in the hopper) just sit there. – user47129 Sep 9 '13 at 23:35
Here are some screenshots to show you: this one, and this one. – user47129 Sep 9 '13 at 23:37
@Scootaloo You need to point the hoppers into each other by shift+clicking on the other hopper when placing one (put a block there, place against the block, remove that block, shift+right click the other hopper so it points into it.) – Unionhawk Sep 9 '13 at 23:44
I knew it had to be finnicky like that, thank you again. I just noticed that little bend to it as well. – user47129 Sep 9 '13 at 23:47
I think you should also add a screenshot so that people can also see the side of the hopper to see that it is connected. That's just a very minor gripe with it though. – user47129 Sep 10 '13 at 0:09

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.