Friday, January 29, 2016

Dial it down a notch

As a mom I am surrounded by noisy things. Not just my kids but their accessories. It seems every toy nowadays has a speaker in it and they rarely have a volume adjustment. Most of them are at a reasonable volume although they will still startle you if you unwittingly step on them.

Then there are the LOUD ones with volumes that can only be described in all caps. You can hear them sound across the house and they are the ones you hope bleed the batteries dead quickly. (They never are.) This game, in an unassuming cute telephone, starts as you pick up the handset and using the plastic tabs that reside inside you can play several games to practice counting, number recognition and more. Seems innocent, and educational right?

Wrong. The thing is LOUD. Loud enough to drown out any conversation while it is speaking. And it will speak as long as it wants, until you replace the handset. Which can come detached by the way, great design flaw. There is an on/off button but no volume control. So one night I had had enough.

I removed the tab holder that twists on to the bottom and removed four small screws that held the blue base to the white top. I found the speaker and was surprised at the size of it compared to the toy. Since I had two very upset children demanding, "Momma, why broken? Momma fix!" it was going to be quick modification without rewiring. After the fact I found this nice instructable with details on adding a resistor to lower the speaker volume. But Momma didn't have time for that.

Ideally I would have found a scrap of cloth to fit over the holes that the speaker fit up against but the lower lips were starting to protrude from my kids' faces. So I cut a few post-it notes and layered them over the holes from the inside of the phone. I think I ended up with five pieces of paper covering it with some scotch tape. The blue housing you see around the speaker slides into the space right in front of the post-it notes in the photo below. In retrospect if I had used cloth it may have been a tight fit getting the speaker back in its place. Upon reassembly it was noticeably quieter.

Now the children can play the game and I don't have to hear it from the other room. And I can present this problem to my students, perhaps as an open ended engineering thought problem. Since we build speakers in our electromagnetism unit (post sound unit and electricity unit) after they create one I can ask students how to lower the volume with a few restrictions:

1. How could you lower the volume by only changing the circuit? (lower current, raise resistance)
2. How could you lower the volume by only changing the speaker? (decrease magnet or electromagnet strength)
3. How could you lower the volume by only changing the outgoing sound wave? (impede the sound waves' travel to your ear)

I've already started a mental list of which other toys need this treatment. Perhaps my in-classroom school intercom ...

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