led spinning top

[illusionist]

i found this spinning top with LEDs and it looks pretty cool.
i took it apart and tried to identify some of the parts, but couldn't!

i'm new to electronics, and don't know very much

here are some pics

**broken link removed**
**broken link removed**

 

[Papabravo]

It looks like resistors, and Light Emitting Diodes, and a black blob. Ah...the infamous black blob. When bright engineers design cute little toys that will be manufactured in the hundreds of thousands(dare I believe millions) they take an unpackaged piece of silicon, mount it to pads on the PC board and drop a blob of epoxy over it. This is so much cheaper than using a packaged chip that they can make money on these gizmos.

The piece of silicon inside the blob could be just about anything from an off the shelf chip all the way up to a processor that implements a setback thermostat, which was where I saw the infamous black blob for the first time.

You never forget your FIRST time - do ya!

 

[illusionist]

the black blob is what was holding me up...

that and the other thing at the top... i figure it's something that detects the motion of the top?

thanks

 

[Papabravo]

Might be a mercury wet contact switch. The rotation of the top sends a blob of liquid metal towrds one end and causes a a pair of contacts to close. As the top slows down the contacts open up and the lights go out.

Can you figure out where the battery is?

 

[evandude]

The black blob is generally called a "chip on board" or COB, I believe.

and yeah, it's a cheap way to mass-produce something... and in some cases it also helps prevent reverse-engineering.

Anyway, making a top like that is definitely doable with a standard microcontroller, if you want some patterns to the lights. Years ago I did a school project where we made a persistence-of-vision toy somewhat like this using a PIC, where we made a wand you waved in the air and it would display messages.

I would guess that the thing in the tube is probably some sort of really simple rotation sensor; most likely, when the top spins, it causes the two contacts to close, activating the lights. A lot of the similar toys I've seen (yo-yos with lights, etc) use something as simple as a little weight on the end of a spring, which flexes outward when it spins. I doubt it would use mercury, that would be more hazardous for a toy kids would be likely to break, and also more expensive than a little spring or similar.

 

[Papabravo]

Offshore environmental regulations might not catch such things. If we can't find suitcase nukes in shipping containers, what's a little mercury in spinning tops? Anyway it could be lots of things -- we just don't know.

 

[justDIY]

the leds look odd too ... is that just the top of a 3mm or similar sized lens poking through, or is it just a bare die glued straight to the board, covered with a dome shaped blobe of clear epoxy?

 

[Papabravo]

I dunno. This one's rougher than a cobb! Sorry, a little farm humor.

 

[jbeng]

Can you figure out where the battery is?

It appears that the battery is behind the board, covered in blue shrink tubing.
JB

 

[illusionist]

Can you figure out where the battery is?

It appears that the battery is behind the board, covered in blue shrink tubing.
JB

yeah they are... there's three

 

[wickedsunny_1988]

please can u get mi the circuit diagram for making a spinning LED using 8051uc

please mail me ne info
on this project to :wickedsunny_1988@yahoo.com
thanks in advance