Flashing Cell phone charms?

[MrBiek]

Okay so this has been bothering me. How do thosed damnable cell phone flashing charms work!! i can't explain why i am obsessed with this it just won't get outta my head and i think i am looking in the worng direction, but i can't find any info out on this

[TheFallen]

My theory is that they've got a tuned helical antenna which picks up the mobile phone bands, say 900MHz/1800MHz etc and the RF energy is put though an amplifier in order to drive the LEDs. I've not opened one up, and only seen them close up briefly, but that'd be my best bet.

Why not buy some, crack them open and take lots and lots of clear photos, upload those photos to flickr (or photobucket etc) and see if anyone could explain exactly what's going on inside one of them.

You would have been FAR better served posting this in one of the more active forums like General Project Help.

[jeanlery2010]

I definitely have one of it. These flashing cell phone charms are definitely so elegant and is performing well with the cell phone whenever I have some private messages though. There's no need to put on in the phone a ring tone because it actually lights up or sometimes vibrate.

[breegeek]

Hey,

I pulled one open and there is this beautifully tiny circuit sitting on top of a wee battery.


I want to figure out how it works or what it's outputting, but my knowledge of electronics is novice at best.

If I fire up my multimeter, what should I be looking for?

I want to hook this guy up to a xBee...

[TheFallen]

You're gonna have to post FAR better pictures than that. I can barely see it. It needs to be clear, so turn on the macro mode, get it so the whole picture is filled up with the board/battery and then go for it.

[zeddie2]

flashing charm

Untitled.jpg (257.25 KiB) Viewed 2471 times

Hi I have also been puzzled by these charms, I took a close picture of the one I have
Its perhaps a little different then the one above as it has a little electric motor ( for a revolving santa )
Any thoughts would be mucho appreciated !

[physics_dude]

From my experience, they only seem to work best with GSM type phones. Note that signature interference you hear in your speakers with GSM phones.
CDMA type phones also seem to work, just not best, i.e. they don't always seem to pick up the signal.

So ya, I suppose the charms are triggering off that interference we hear with GSM phones.