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Dirt Cheap Acoustic Guitar Pickup Answered

I am concerned about the health and safety aspects of the instructable of "Dirt Cheap Acoustic Guitar Pickup by Xuthal". The project encourages people to take apart a smoke detector to obtain a piezo sounder. However no warning at all is given by the author that there may be radioactive material in the device, or how to recognise it and how to deal with it.

I tried to post a warning on the article but for some reason it hasn't worked. I could not see how to flag up the item so I am posting here.

Whilst the manufacturers of smoke alarms play down the dangers of Americium 241 dioxide (the radioactive material), they would most certainly not condone opening up a smoke detector sensor. Am O2 will most likely pass straight through the gut due to its insolubility, so your readers are probably safe from ingesting it. However, if the source is fractured into dust particles, it could be inhaled and will lodge in the lung for a long time. Being an alpha emitter the Am241 will very likely end up causing a lung cancer.

I think this instructable is highly irresponsible and should be removed. In any case the item taken from the smoke detector, a piezo transducer, is readily available from any hobby electronics supplier and costs less than the battery to power the detector in the first place!



4 years ago

Your comment is on the project in question.


4 years ago

a) There is a flagging option for all postings and Instructables.
b) Posting a comment in this regard certainly would work - if you flag it as "inappropriate" someone with the rights for it will take a look for sure.
c) Americium 241....
If you do your homework you quickly realise why the stuff is only in a slotted aluminium can with just a simple plate at the bottom.
Although being radiactive it is barely able to penetrate anything and the amount of Gamma rays can be neglected.
There is less than half a microgramm of Am241 inside a smoke detector.
So unless you actually force the aluminium can open, use a microscope to locate the tiny drop of Am241 and ingest it you would be totally safe here.
If you change the battery of a smoke detector you open the plastic housing - you wont get more contact to the radioactivity by soldering off two or three connections for a buzzer.

So what again was your concern? ;)


Reply 4 years ago

Thanks for your reply.

Firstly, I would like to say that I think Instructables is an excellent site and fulfils an excellent need by encouraging young people to work creatively with technology and engineering. But I have to make the following comments.

Hmm-m. "If I do my homework---" ?? I'm one of the guys who makes up the homework questions for things like this. Physics teacher, with an element of nuclear engineering in one of my degrees, and some minor contract work to the nuclear industry in the past.

Am241 is indeed a weak gamma emitter, but it is also an alpha emitter (it has to be, to be of use in a smoke detector). The form of the Am241 in a smoke detector is in AmO2 (Americium dioxide) and as such is pretty insoluble in water. That is why we are allowed to dispose of fire alarms in land fill. The AmO2 will stay in the sensor for some considerable time. It will also pass straight through the gut as, being insoluble, it cannot be digested and absorbed by the body.

However, as I stated to you in my last e-mail, if the AmO2 is fractured in any way that allows it to be inhaled, it will lodge in the lung - and to quote yourself, "if you do your homework" - you will know that alpha emitters are relatively safe outside the body because medium energy alpha particles do not penetrate our dead skin, but when lodged in the lung they will almost certainly prove to be fatal after 20 years or so. There is absolutely no argument about this.

Thus, this instructable ""Dirt Cheap Acoustic Guitar Pickup by Xuthal" has to be removed from your site or sufficiently modified with an alternative source for the piezo transducer. As I have already pointed out suitable devices are available for $2 or less.

My worry and objection to this instrucatable still remains. There are no instructions on how to recognise the sensor containing the radioactive material or how to deal with it. You yourselves have just confirmed that the AmO2 is contained in a flimsy aluminium case so what is to stop a youngster ripping it open to find out what is inside? Your rather cavalier and, I have to say, uniformed answer has me further worried.


Reply 4 years ago

I do understand your concerns but I fail to see the problem happening.
It would take brute force to damage the vessel for the radioactive material - I have taken quite a few detector apart for project and never EVER had any issues unsoldering and disposing of the Am241.
If you have so much health concerns check the Ibles with weapons, using dangerous chemicals or those telling you to make rocket fuel.
After 6 years I also feel to see the urgency to remove such an ible.

I would have to ask to remove all ibles containing flouroscent lamps as they are dangerous too - especially if you inhale the dust from a broken lamp.
Not to mention those ibles involving mains power - people can get electrocuted.
There are enough ways to get a good piezo, a smoke detector is not the best choice I admit, but did you ever heard of single case where a smoke detector caused bodily harm due to the radioactive material inside an aluminium can?
Check the story of David Hahn, the radioactive boy scout ;)
I really doubt a single smoke detector is a health and safety concern if handled correctly.