[MCPE-14791] Comparators don't activate when they're getting power from detector rails Created: 04/Jun/16  Updated: 19/Mar/17  Resolved: 06/Nov/16

Status: Resolved
Project: Minecraft (Bedrock codebase)
Component/s: None
Affects Version/s: 0.14.3, 0.15.0 Beta build 1, 0.15.0 Beta build 2, 0.15.0 Beta build 3, 0.15.0, 0.15.1 Beta 1, 0.15.1, 0.15.2, 0.15.3, 0.15.6, 0.15.90.0, 0.15.7, 0.15.90.1, 0.15.90.2, 0.15.8, 0.15.90.7, 0.16.0
Fix Version/s: 0.16.1

Type: Bug
Reporter: Daniel R.
Resolution: Fixed Votes: 3
Labels: detector-rail, redstone, redstone-comparator

Attachments: PNG File 300px-Detector-comparator-diff.png     PNG File Comparator-Detector-Rail-Bug-0.16.1.png     PNG File with_redstone_signal.png     PNG File without_redstone_signal.png    
Confirmation Status: Confirmed
Platform: Android
CHK:

 Description   

My device = Kingzone K1 turbo

I exspected that the comparator' back is shining AND the comparator makes a redstone signal.

I saw the comparator was not activated, even it did not make a redstone-signal, normally the comparator should do this!

How to reproduce:
1. Place a comparator
2. Place a detector rail as a redstone-power-source at his back
3. Place any type of minecart on it
4. You will see, the comparator is not making anything

UPDATE: As of 0.16.1, this bug is only partially fixed: Comparators can receive power from redstone dust that is powered by a detector rail, but they cannot recieve power directly from the detector rail. Sometimes, however, placing a comparator next to a detector rail will cause it to be momentarily powered when it is first placed, giving off a pulse of at least 1.5 rticks (3 gameticks), or however long a pulse is required to be in order to invert a redstone torch in MCPE. See this video for a demonstration: youtu.be/9E4gOTQ4W7c



 Comments   
Comment by Zeb [ 06/Nov/16 ]

DrAwesome4333 You're right. My mistake. I'll close this issue as fixed now. However, the occasional short pulse the comparator gives off when initially placed sometimes is still a bug, and I've reported that in a new ticket as MCPE-18008.

Comment by [MCPE Mod] Dr.Awesome4333 [ 06/Nov/16 ]

Isn't this fixed now ?
When a comparator is next to detector rail it will measure the contents in the mine cart. Fill a minecart with chest witn some items and it works. So the "half not fixed" part is WAI.
This image from the the wiki shows the correct results

Comment by Zeb [ 05/Nov/16 ]

As of 0.16.1, this bug is only partially fixed: Comparators can receive power from redstone dust that is powered by a detector rail, but they cannot recieve power directly from the detector rail. Sometimes, however, placing a comparator next to a detector rail will cause it to be momentarily powered when it is first placed, giving off a pulse of at least 1.5 rticks (3 gameticks), or however long a pulse is required to be in order to invert a redstone torch in MCPE. See the newly attached screenshot. I will make a video on this shortly.

Nevermind, I'm stupid. This is WAI. (Except the pulse that sometimes happens... but that should be a separate report.)

Comment by Daniel R. [ 22/Jun/16 ]

I updated the description to correct some grammar and spelling errors to prevent misunderstandings. Also I have added some labels.

Comment by PHO [ 07/Jun/16 ]

Thanks. I updated the summary to clarify the point.

Comment by Daniel R. [ 06/Jun/16 ]

I updated the description for detector rails only, as I tested it with other power sources myself and the comparator worked as it should work. So the problem is only with detector rails.

Comment by PHO [ 05/Jun/16 ]

I don't know about 0.15.0 beta but in 0.14.3 this only happens when the power source of a comparator is a detector rail with any kind of minecarts on top of it.

Comment by kaleb418 [ 04/Jun/16 ]

Confirmed for 0.14.3

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