(Way, way, way off topic) Any sound engineers in the house?

[Omega Man]

I work in long term care and patient falls are a real problem. For the past 15-20 years many hospitals and long term care facilities have turned to personal alarms to assist in fall prevention. These alarms alert staff that a pt at risk of falling by making a loud even ear splitting alarm. They can built into beds but the most common types of personal alarms are the pressure pad and tab alarm. The type I'm inquiring about in this thread though is the tab alarm. These are usually a small plastic box(about 2.5" x 3-3.5") that has a small board inside with tiny electronic components that use a regular 9 volt battery with a metal contact point on the top that a magnet with a long adjustable string with a clip at the end that attaches to the pt's gown or clothing. The string pulls the magnet off the contact point on the box and it alarms.

Here's the problem, they stop alarming. Some don't even last a week sometimes only a couple days. These alarms do get dropped on the floor, sometimes often but I don't think that is the problem. Most of them show no signs of damage on the outside and fail, some are beat to sh*t and still work fine for months(6-12).

I don't know what actually makes that ear splitting sound. I doubt it's a speaker, they are so loud everyone hates them, pt's their families and of course the staff.

Whatever it is could they be burning out some how? Sometimes instead of going silent they make a soft "tic tic tic tic tic" sound.

~O~

 

[mcgovern61]

Tab alarms use piezo type signal devices. I would venture that they would fail as a result of getting wet. (Think incontinence care!) It does not take much to break a piezo. We use them on boats all the time for engine alarms. They are small, piercing and can be heard great distances and do not take much power to set them off.

The only other issue I can think of for tab alarms is the actual tab itself not releasing the switch inside the unit when the tab pulls out. The switch can get stuck because of being dirty (which can sometimes happen from housekeeping cleaning them and leaving alcohol in the tab).

Just my thoughts.

 

[Omega Man]

Ahhh, wetness isn't a problem but what about shock as in being dropped?

~O~

 

[Steve83]

Some magnets can lose their magnetism from being dropped. Even the Honda manual says to not drop the alternator rotor for this reason. A possibility...

 

[slabghost]

Electrical and electronic devices can be fickle. I've experienced much the same result from different devices some fail quickly others seem to take a lot of abuse yet function a long time. Could be cold solder joints or moisture (humidity) or even just dust inside causing issues. Opening some of the failed devices might reveal the trouble with some close examination. Might be something as stupid as a contact out of alignment.