Inspection of an Expired Smoke Detector.


Introduction: Inspection of an Expired Smoke Detector.

About: Update 12 September 2017: A very special thanks to Sam Elder, a manager here at Instructables, who tracked down the cause of my lost publications and fixed the issue. Take a bow Sam!

This old smoke detector in my home has become a nuisance by going off on its own.

Step 1: The Dates.

The service life on these cheap smoke detectors is about 10 years after which it becomes unreliable.

Step 2: The Tool.

My Handy pen knife came in useful in this job.

Step 3: Popping It Open.

Using the knife blade, I popped the 3 clips holding the cover. Now the guts of the smoke detector is available for inspection.

Step 4: The Internals.

Here the ionization chamber and piezo speaker can be seen in addition to the circuit board. Such a shame it cannot be refreshed.

Step 5: Salvage.

The 9v battery clip is perfectly good so I removed this for use in future projects.

Step 6: The End.

The rest of the smoke detector is good for garbage now. These detectors contain a very tiny amount of Americium as the radioactive ionization source. Once the ionization chamber is not interfered with, it is perfectly safe to dispose in regular household garbage. Bye-bye old detector!



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    4 Discussions

    While I understand you thinking the rest can go in the trash, it can not. It is a hazardous waste. The ionization chamber contains a radioactive material. It it should be disposed of properly.

    3 replies

    No restriction from the federal level on disposing of smoke detectors under 5 μCi in the US (source: According to the source, modern consumer units are under 1 μCi.

    That being said, anyone reading this should not attempt to open the ion chamber. Even though consumer grade detectors have a tiny amount of radioactive material, Americium is a "bone seeker". Meaning if it gets into your system your body tends to metabolize it and deposit it in your bones instead of passing through your urine.

    Ha! Since when. There are no requirements on the device or my local municipality for specialized disposal of that detector. If your area has that requirement then say YOUR area.