AM312 PIR issues

Not long after making my BRUH multisensors I realized I had to modify one to have 2 PIR sensors.

Editing the code I managed to do just that. PIR installed. Tested and works great.

It’s a multisensor in middle of a corridor with 2 AM312s pointing in opposite directions.

About a month later one of the PIRs started to have ghosting or signs of failure. The failures were becoming more and more constant.

The build was prior to getting a soldering iron so the wires were Gerry-rigged to provide power from the VIN of the Nodemcu. I thought it might be an inconsistent connection issue.

I later purchased a soldering iron and flux at Daiso (again) made a proper wiring setup.

The AM312 still acted oddly. Swapping it out for a new one worked. Putting the erratic sensor on a a spare nodemcu flashed with the same BRUH code revealed the same erratic behaviour. So it wasn’t the poor wiring nor the new soldered job.

Later as I was one PIR down and using more than I thought I ordered a couple more. In my haste I fried one by inverting pin positions when inserting it…

See pinout labels.

Using the last one I assumed it worked. Inserted it in and it did work for a week.

Then the new AM312 started acting up erratically on a new setup.

I contacted the seller on AliExpress. For a few days it was a back and forth of messages.

For a few messages they said they would try to figure out the problem. Great I thought. But they never asked me about my setup or what I did.

I was thinking they were trying to run down the clock as we were now 13 days in the 15 days to launch a dispute.

I even made a little video about my situation demonstrating the new PIR didn’t work and sent it to them via Dropbox link despite their request to send them an email. (I’d rather keep everything in one place for AliExpress to screen at a later date should the need arise)

In the end they asked what I wanted. I told them to send me a new one as the sensor they sent was defective.

Finally they agreed after realizing this 100¥ issue was just not going away.

In the meantime I cannibalized another sensor and the erratic problems stoped.


I have received a new AM312 last week. They actually sent a new one. I’m a little surprised. Although I haven’t tested it yet… that will be in an update to this post.

In another post I mention that the power source was the cause of erratic behaviour. In this case however the thought didn’t occur to me as I had left in place my new iPhone charger that I use to test units. Here


Update tested the replacement unit that was shipped. Works as it should.

I’m honestly surprised they shipped me a new one at all. I’ll chalk the confusing messages back and forth up to miscommunication. It’s important to state what you want directly and simply.

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