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Perikles
2010-Nov-26, 11:15 AM
This is really a Q/A thread, but not on an astronomical topic. I have a tea cup, or rather mug, which plays a rather annoying tune when picked up, and stops when you put it down. This is clearly some capacitance effect with the mechanism in the base of the cup, which as far as I can make out, is built into the china matereial of the cup. My question is what energy source is used to generate the 'music'. The mug is 20 years old, and still going strong.

Strange
2010-Nov-26, 11:23 AM
Magic?

Perikles
2010-Nov-26, 11:42 AM
Magic?That's what I suspected, but it's nice to have it confirmed, thanks.

Jens
2010-Nov-26, 01:23 PM
I'm thinking magic too, probably something from Hogwarts.

The other possibility would be a spring. When you pick it up, a spring somewhere is released, and as it is released, music is played. When you put it back down, the spring returns to its place. So the power is coming from the action of picking it up.

But that's too boring. I think we should go with magic.

megrfl
2010-Nov-26, 02:15 PM
Even though you say it is annoying, I think the idea is neat (it's the first I'm reading of a tea cup that plays music) and furthermore, I can't believe it's still working after 20 years. Who is the manufacturer, or better yet, who distributed it? Hallmark?

As far as what mechanism is within it, I would say it is a motion chip and that it is not so much a solar cell but most likely a cell that receives its energy from the heat of the liquid within the mug. I bet it is not microwave safe. hehe.

With further thought, you shouldn't use it -- it's probably emitting some kind of lethal radiation.

Good luck. :o)

Perikles
2010-Nov-26, 02:29 PM
As far as what mechanism is within it, I would say it is a motion chip and that it is not so much a solar cell but most likely a cell that receives its energy from the heat of the liquid within the mug. I bet it is not microwave safe. That's a good point about the microwave. But if it receives heat energy from the tea, what is the mechanism?

Strange
2010-Nov-26, 02:33 PM
most likely a cell that receives its energy from the heat of the liquid within the mug

That was my first (serious) thought. Some kind of reverse-Peltier effect. But I'm not sure it could be done cheaply or efficiently enough. We might have to hit the mug with a hammer to find out.

Strange
2010-Nov-26, 02:33 PM
hit the mug with a hammer to find out.

Er ... the drinking vessel, not Perikles.

Ivan Viehoff
2010-Nov-26, 02:37 PM
Look here.
http://www.b2bfreezone.com/product-search/ceramic-christmas-mugs.htm#
There are two musical mugs here, the top one and the third one. The details for the third one indicates that the on/off mechanism is a light sensor. You could test that on yours by seeing if it turns off when put onto a clear glass surface, or with opaque material held underneath it but not pressing on it.

In terms of the power source on yours, I'm guessing that the battery was just over-specified, and the power consumption low. No doubt you don't use it very often. My small daughter has something about christmas/birthday cards and keeps a selection of old ones in a tin, including musical ones, which still seem to carry on working for a long time.

TrAI
2010-Nov-27, 12:35 AM
This is really a Q/A thread, but not on an astronomical topic. I have a tea cup, or rather mug, which plays a rather annoying tune when picked up, and stops when you put it down. This is clearly some capacitance effect with the mechanism in the base of the cup, which as far as I can make out, is built into the china matereial of the cup. My question is what energy source is used to generate the 'music'. The mug is 20 years old, and still going strong.

Hmmm... While it probably is possible to make a musical mug driven by the heat of the liquid, it is rather unlikely. I wouldn't suppose someone would pay enough for it to be viable to install a thermopile inside what is just a novelty item. It also seems unlikely that the device would use a capacitive sensor, though it isn't completely impossible, a sensor like this would be an active device, and so a battery would be unlikely to last that long in a device using it. It would be much cheaper to use a photo detector, like a photo transistor that would detect the light when the mug is picked up.

I would suspect the mug is made in two parts, the mug itself, and the bottom, and then the circuit is placed inside the compartment under the mug, and the bottom placed in afterwards, as I see no way for electronics to survive the high temperatures that is used in firing a porcelain object. The music circuits are one time programmable devices, and the manufacturers will program them with the message or music the costumer wants to order, so I should think it is more practical to be able to make up a standard batch of circuits and mugs, and then blow the circuit and have any image or text painted, printed, screened, sublimated or what ever onto the mug before final assembly.

My guess is that the circuit is just driven by normal button or coin cells, and that the circuit has a modest power usage. Also, I hardly expect anyone would use such a horrid thing much anyway, so there is probably not much demand on the cells(At least I would never want to use a cup that makes noise at me).

Perikles
2010-Nov-27, 09:53 AM
Er ... the drinking vessel, not Perikles.Funniest post I've seen on BAUT for ages. I have just confirmed that light is indeed the on/off mechanism. The base of the mug is a kind of plastic, presumably glued in after firing the mug. And I really like the idea that the tune is so terrible that you avoid using the mug, hence prolonging the life of a built-in battery. Thanks everyone for your input.

JohnD
2010-Nov-28, 11:25 AM
Perikles,
Clearly your mug has slipped from the reality of the Hitchhikers Guide to the Galaxy into this reality, an entirely possible event, given that the impetus to the invention of the Infinite Improbability Drive was a really hot cup of tea.

A really HOT cup of tea was the power source for the "Heart of Gold", which might be found, well, anywhere.
John

Trebuchet
2010-Nov-28, 04:00 PM
Since you don't like the tune, and don't use the mug because of it, how about a little destructive testing? First just try to get the plastic piece off the bottom and open it up. If that doesn't work, use a hammer...

ETA: If you want to save the mug but get rid of the tune, a little black tape on the bottom will probably fix the problem.

Why yes, I am an engineer! :)

Perikles
2010-Nov-28, 05:30 PM
ETA: If you want to save the mug but get rid of the tune, a little black tape on the bottom will probably fix the problem.

Why yes, I am an engineer! :)Yes, but I was actually just interested in whether there was a renewable energy source inside it, which seems unlikely. I had not realised it was light sensitive. I could of course just leave it outside in the sun and see how long it takes to die.

Strange
2010-Nov-28, 05:53 PM
Why yes, I am an engineer! :)

We knew that as soon as you said, "if that doesn't work, use a hammer" !

rommel543
2010-Nov-30, 04:49 PM
We knew that as soon as you said, "if that doesn't work, use a hammer" !

I'm a software developer and I use the same statement when dealing with problem computers.