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Chips in smoke detectors Answered

I have a bunch of smoke detector circuit boards all of which have IC chips. All of them have slightly to widely different numbers, some Motorola, a philips, etc. 
The main question I have is what type of chips are these as far as function goes? I tried looking these up but so far nothing absolute.

Some numbers I remember are 8506, 8605, 8502; other numbers are way different and I don't remember what they are.


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Jack A Lopez
Jack A Lopez

3 years ago

Um, are these from ionization type smoke detectors?

Do they still have the chamber with the tiny Am-241 alpha source? I mean, that is the truly interesting part.



Perhaps you already know this.

Regarding the IC, I think usually there is just one of them, and if you can look at the data sheet for Motorola's MC14467,


I think this IC is a typical example. There is some kind of really high impedance comparator, like with FET inputs or something, for to sense a DC voltage on the ionization-chamber thing. Also there is an alarm sound circuit, capable of driving a piezo speaker at earsplitting volume. And that is pretty much it.

So, I am guessing an old smoke detector board could be re-purposed as an alarm, or annoying noise maker, but I am not sure what else it, a board without the ionization chamber, could be used for.

Regarding the numbers you mentioned, {8506, 8605, 8502}, I do not recognise these, but that does not mean the data sheets for your ICs are not out there somewhere.

Smoke detector IC is kind of niche thing anyway. I am expecting the total number of smoke detector ICs out there to be small, so maybe try just asking alldatasheet, or some other IC data site, to show you ICs with "smoke detector" in the description.


This is kind of shotgun approach, but one of the ICs that shows up in that result might be similar, or the same, to the ones you have.


3 years ago

The numbers alone are somewhat meaningless. You need the letters coming with it and/or the manufacturer.

Those stuff made for the mass market with only one chip inside will most probably have special chips that cannot be used for much else.


Reply 3 years ago


These MFG would not want the insurance risk if the let you change the code and burn your house with NO Alarm !