Vibration Activated LED Ball (for aquarium)

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Vibration Activated LED Ball (for aquarium)

Postby freeflashstuff » December 21st, 2012, 12:35 am

Hello, all. I recently picked up some "Waterproof LED Aquarium Ball" from the local dollar store, and they were all corroded on the inside. I took a wire brush to the insides, and I was able to get a couple of them working, so I took one of the others apart.

When one is tapped or rolled, it lights up the LEDs and fades them off after a couple of seconds.

What I would like to know is how to duplicate this and use whatever color LED I want with a 2032 battery or something similar. I'm including pictures below. (They are quite large (14 Mega Pixels), so I am including URLs rather than using IMG tags)

https://dl.dropbox.com/u/43771844/Pics/DSCF1142.JPG
https://dl.dropbox.com/u/43771844/Pics/DSCF1141.JPG
https://dl.dropbox.com/u/43771844/Pics/DSCF1140.JPG
https://dl.dropbox.com/u/43771844/Pics/DSCF1139.JPG
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Re: Vibration Activated LED Ball (for aquarium)

Postby UAirLtd » December 21st, 2012, 8:51 am

Without knowing more and probing the device (i.e. probing it with a multimeter), I would hazard a guess that the black cylindrical device in the middle is a momentary contact switch, which could be as simple as a spring, which when moved wobbles and touches a contact - either a rod in the centre, or the housing. When the device is moved, the switch momentarily completes a circuit charging the capacitor.

Then, either the capacitor itself supplies the LEDs, in which case the LEDs will fade out as the capacitor discharges; or the capacitor is part of an RC circuit which controls the power to the LED via a transistor circuit operating in the linear-region. In either case, you have a simple circuit that is capable of fading out LEDs after some time.

Replace the LEDs as you like, but the voltage of a 2032 cell may be too low to drive some LED colors to full brightness. Pick LEDs with Vf in the right range for your cell.
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Re: Vibration Activated LED Ball (for aquarium)

Postby st2000 » December 21st, 2012, 9:15 am

I take it there's nothing but the batteries on the other side?

Well, I think I see 2 transistors, a large cap and some SMD resistors. But the problem is the "thing" in the middle. No doubt it contains the motion switch. But what else?

Regardless, these things are very cheaply made. Or, to put it another way, it's likely to cost you more to duplicate it then to just go out and buy more of them.

So, if you are having fun, go for it. Try to duplicate it. But if you are looking for something interesting that works in a similar way...
Build and Arduino knock sensor and connect that up to something like a tri-color LED:
http://youtu.be/4NrRqs10BCY
(I like using lmgtfy because it is automatically up to date and let's you pick where you want to go.)
http://lmgtfy.com/?q=arduino+knock+project
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Re: Vibration Activated LED Ball (for aquarium)

Postby freeflashstuff » December 21st, 2012, 5:17 pm

UAirLtd wrote:Without knowing more and probing the device (i.e. probing it with a multimeter), I would hazard a guess that the black cylindrical device in the middle is a momentary contact switch, which could be as simple as a spring, which when moved wobbles and touches a contact - either a rod in the centre, or the housing. When the device is moved, the switch momentarily completes a circuit charging the capacitor.


That would be correct. I did some looking around, and that cylinder is a SW-18015P "Vibration Switch." They look to be pretty cheap (~USD $12 per 100 pc.). As for the resistor and the transistors, I can't read what they say. I'll pull out my multimeter in a bit and measure the resistor.

st2000 wrote:I take it there's nothing but the batteries on the other side?


That is correct. It normally has 3 AG3 cells on the other side. I removed them to get a better look at the board.
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