This post was just migrated to the car mechanics site:

https://mechanics.stackexchange.com/questions/67998/detect-if-a-can-node-is-transmitting-or-receiving

Why?

It is a 100% electronics question and has absolutely nothing to do with cars at all. Car mechanics can't answer questions about the behavior of CAN transceivers or about line impedance.

• As a user with close vote privileges on MV.SE I voted to close it there, AFAIK closing a migrated question reverts the migration. The user in question has already asked questions there, so it's their informed choice to get advice from us, and not from them. We should respect that. – Dmitry Grigoryev Jun 14 '19 at 6:37
• @DmitryGrigoryev In addition, we should respect those who had already made an effort answering the on-topic question on this site. – Lundin Jun 14 '19 at 6:42
• Also, the migration transformed our differential tag on the question into MV.SE's differential tag, which is completely different. Did I already say that I hated adjective tags? – Dmitry Grigoryev Jun 14 '19 at 6:48
• @DmitryGrigoryev "... I hated adjective tags" Moreover differential is one of the most common "special" adjective across a huge range of different scientific fields, so it's particularly nasty! By "special" I mean "stick that word to a substantive and you have a cool sub-field" :-) Compare (just off the top of my head) differential amplifier, differential gear (mechanics), differential analysis (math), differential diagnosis (medicine), differential psychology, differential stress (geology, civil eng.) and more. UGH! – Lorenzo Donati -- Codidact.com Jun 15 '19 at 15:16
• It's back over your way now :-) – Rory Alsop Jun 19 '19 at 21:59

It shouldn't have been. Migration should only happen when something is OFF TOPIC HERE, and on topic there. This is clearly an on topic Electrical Engineering question. The mod who migrated it single-handedly does this to any question that even mentions a car, arduino, or raspberry pi to those other stack exchange sites.

Flagged for migration review by Mechanics mods.

Update: The question has been closed on Mechanics as Migration Rejected. It can be voted to reopen here now.

Further update: The question has been reopened here.

• For what it's worth, a few hours ago I flagged the migrated post with: "You may already be aware of this one; I wanted to be sure. There was a question migrated from EE to MV that has caused a kerfuffle :) You may want to reverse the migration and give it back, if possible. Question [here], Meta discussion [here]. Thanks!" The flag was declined: "declined - flags should only be used to make moderators aware of content that requires their intervention" – bitsmack Jun 13 '19 at 20:51
• @bitsmack Once a question is migrated it's up to the users of the target site to decide whenever they want to keep it or not. It was not your call. – Dmitry Grigoryev Jun 14 '19 at 6:44
• @DmitryGrigoryev I'm sure you're correct. I don't understand how the users (as opposed to the mods) could choose to accept or reject it, though, so I had assumed it should have been the mods' responsibility. It looks like I should look up the rules of migration! – bitsmack Jun 14 '19 at 8:49
• @Users can reject a migration by voting. A mod would have to decide that single handedly, based on your flag. Most of the time mods prefer to let the community decide – Dmitry Grigoryev Jun 14 '19 at 18:52
• @Dmitry except here where a mod prefers not to let the community decide. – Passerby Jun 14 '19 at 21:05
• I've added a link to the returned question on EE.SE to your answer. I hope you don't mind. Thanks to you and @W5VO for reopening it. – bitsmack Jun 21 '19 at 18:35

I consulted with the Mechanics.SE mods a few days ago. They said that the question is within their knowledge, and that they had similar questions before.

update:
Notice the upvotes on that question about CAN. The question and one of the answers got upvoted after the migration to Mechanics.SE .

• But the question has nothing to do with cars! CAN is used everywhere, not just in cars. – Lundin Jun 12 '19 at 7:45
• The fact they say it's "within their knownledge" doesn't necessarily means it makes sense to migrate it. Home mains cabling is within our knowledge, but do you want all cabling questions from DIY.SE to end up on EE.SE? The way the question is fomulated makes it much more fit to the EE site than Mechanics. And it already had answers from EE users. – dim Jun 12 '19 at 8:41
• Looked very much an EE question to me. – MCG Jun 12 '19 at 12:47
• I mean, by that logic we should migrate everything that uses SPI and I2C to the Arduino stack exchange because they have "experience" with SPI and I2C. It wasn't off-topic here, so it shouldn't have been migrated. – W5VO Jun 12 '19 at 17:38
• The real problem is the SE has no mechanism for addressing this kind of pattern of moderator misbehavior. – Chris Stratton Jun 13 '19 at 5:47
• Different logic, @W5VO. Arduino.SE moderators wouldn't approve SPI and I2C questions migrated to Arduino.SE . – Nick Alexeev Jun 13 '19 at 8:03
• @NickAlexeev, no, it's the same logic. It was an absolutely ridiculous decision to migrate this question. It was very, very clearly on topic here and should have stayed that way. – MCG Jun 13 '19 at 8:18
• Nick, could you perhaps comment on questions you plan to migrate before you do, and refrain from a migration it you get negative comments from the community? Especially on questions which have been upvoted or answered. – Dmitry Grigoryev Jun 14 '19 at 7:17
• @DmitryGrigoryev That's a good idea. Judging by the response to this, I'd say it is a good way to go – MCG Jun 14 '19 at 7:36
• ??? What ??? The question didn't mention one single time the word car or any other mechanical term. How on earth that was a defensible migration action?!? So the only apparent logic in that migration is "CAN is heavily used on cars, the post asks for CAN then let's migrate it to mechanics.SE". The same logic is applicable to a dozen other topics (e.g. LED lighting, ABS plastic, glass windows, fire retardant carpets, etc. ). So let's dump on mechanics.SE any post on the SE network mentioning something that is used on cars! Come on! ... – Lorenzo Donati -- Codidact.com Jun 15 '19 at 12:17
• ... A moderator did a silly mistake, OK, it happens. Apologize, try to revert the action and get over it. Just don't add insult to injury by defending such a mistake! – Lorenzo Donati -- Codidact.com Jun 15 '19 at 12:18
• @NickAlexeev Unfortunately, I don't spend much time in chat, so I will likely miss on such migration announcements. What I will almost certainly see is a comment on a question I'm about to answer. – Dmitry Grigoryev Jun 16 '19 at 9:59
• @Loreno I'm not defending a mistake. He asked me "why". He wanted to know my rationale. I answered what I was thinking at the time when I was arranging the migration of the question. – Nick Alexeev Jun 16 '19 at 14:08
• Well, sorry, It doesn't seems so (maybe a communication mismatch). Your recent update to your post seems to be reinforcing the idea that you think the migration was OK. The fact that someone on that site had the knowledge to give nice answers doesn't mean it was OK to migrate it. It is irrelevant. If someone migrated here a question from SO about, say, the Lua language, I could probably write quite a decent answer. And Lua is used in embedded systems. But if the question weren't about embedded systems, would my good answer indicate that it was OK to migrate it here? I don't think so. – Lorenzo Donati -- Codidact.com Jun 16 '19 at 20:36
• Notice the upvotes on that question about CAN. The question and one of the answers got upvoted after the migration to Mechanics.SE Yeah, cause I upvoted them as good. Not to mean they belong there. – Passerby Jun 21 '19 at 3:21