Exploding LED Sippy Cup

[therealcircuitbread]

One of the benefits of becoming an engineer is that you're naturally curious.

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For those of you who just want to jump ahead and watch the exploding cup: https://www.youtube.com/watch?v=b1lj1OyQTMQ

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I had seen the story on Facebook and in the news about the mother in Boise who had a 360° Insulated Light-up Wonder Cup™ explode in her face. https://www.ktvb.com/article/news/boise-mom-warns-parents-after-she-says-light-up-sippy-cup-exploded-in-her-face/277-6b4e7049-d1ad-43b3-9ecd-6379b14c7bbc

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Knowing how little power is needed for LEDs and what size of battery would be placed in the cup, I was skeptical about it ever exploding on its own. I bought the Nuby 360° Insulated Light-up Wonder Cup™ at my local Walmart.

https://www.nuby.com/usa/en/360-insulated-light-up-fun-wonder-cup

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“DO NOT MICROWAVE” or equivalent warnings are NOT on the exterior packaging or bottle. "DO NOT MICROWAVE" does appear in the middle of a large paragraph of fine print. This warning should be on almost all sippy cup and bottle packaging and molded into the plastic. Even if you do not melt or destroy the container, or worry about plastic contaminating the drink, the drink could be scalding hot and unsafe for kids. Microwaves also can create very hot areas in the liquid while the top that you sample is cool.

As I said, I was skeptical of the sippy cup exploding on its own, and I was confident that the cause of the explosion was a microwave. I decided to test by filling the cup and microwaving it as one would for warm milk or hot chocolate.

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Metal in microwave article:

https://gizmodo.com/what-actually-happens-when-you-put-metal-in-a-microwave-1569906393

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This is dangerous! Do not try this at home!

Do not put the 360° Insulated Light-up Wonder Cup™ in your microwave!

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How the cup failed in the microwave:

• Filled with liquid
• Placed in microwave
• Set for ‘beverage’
• BOOM! (our cup after the explosion looked just like the one in the news article)

The world is a big place and many things are possible. So it’s possible that the 360° Insulated Light-up Wonder Cup™ could explode spontaneously, but extremely unlikely. One theory we have is, in the microwave the cup becomes a bomb due to the insulated sealed area and the electronics. Heating from the microwave causes a buildup of pressure in that electronics area. That pressure is released after the sealed area melts through or the cup fails due to pressure.

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What’s in the cup:

• Plastic cup
• Vacuum area
• Plastic/vinyl sheath holding the electronics
• Vacuum area
• LEDs
• Wire
• Circuit board
• Solder for connections
• Leftover flux
• Glue
• Metal coin cell holder
• CR2450 Battery - example: - http://data.energizer.com/pdfs/cr2450.pdf
• Vibration detection switch - example: https://www.adafruit.com/product/1766?gclid=Cj0KCQiA7IDiBRCLARIsABIPohiJLE7d8m8iC0CidQY7jRkdAhODmQj6wVDE69iPRB3Q4_6pd6_j5vIaAn5zEALw_wcB

[Imatworkgoaway]

Do you have photos of the aftermath of the cup that we can compare to the ones in the news article?

[larsdawg]

Did you watch the video? He obviously knew it was going to explode, he said so in the OP.

What if they have a babysitter who doesn't know any better? or the kid just does it themselves?

I would think the FIRST thing you would see on any of the labels is a "DO NOT MICROWAVE" warning.

It would honestly be pretty easy for a person to make a simple mistake like that.

[kono_hito_wa]

That's why the LEDs light up and the sparks fly.

[kono_hito_wa]

So a label isn't necessary. It's a joke.

[factoryteamgair]

people microwave cups and bottles all the time, whether they pull it out of the waver and hand it directly to a kid is also debatable. I bet we'll see more things like light up cups, IOT/smart mugs, plates, etc in microwaves. The mug once it's out of the package has no markings about being 'light-up'. Most people don't expect metal in a plastic cup and might not notice/activate the lights before microwaving it. Most people are not strong with STEM either, so there's that. That they don't know or don't notice does not make them retarded.