Safety goggles in Arduino class?

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microscope
 
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Safety goggles in Arduino class?

Post by microscope »

I am going to teach an Introduction to Arduino course this fall in my son's highschool with the ARDX kit. One issue we are grappling with is safety, specifically whether we should make it mandatory to wear safety goggles at all times. Assembling bread 5-Volt board circuits is far less dangerous than chemistry lab, but it is conceivable that a wrongly-connected component (e.g., LED without series resistor) would overheat and explode.

May I ask anyone who has taught a similar class (breadboarding only, no soldering) about their safety policies? Do you recommend or require safety goggles? Do participants have to sign a release form regarding injuries? (And, yes, we'll also tell the kids not to stick anything into the 110-Volt outlets ...)

Thanks for any help,

Richard

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markofzero
 
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Re: Safety goggles in Arduino class?

Post by markofzero »

At our Junior College, we require safety glasses because of "flying" leads being cut from resistors and such.
Exploding capacitors are more likely than leds.

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zblaxell
 
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Re: Safety goggles in Arduino class?

Post by zblaxell »

I have experience being a high school student working with 5V electronics on breadboards.

I've personally blown up electrolytic capacitors (who hasn't?) and a ceramic-package power transistor (chunks of ceramic flying past my head, bouncing loudly off the far wall of the room). I've set resistors on fire (they will burn with a little candle-like flame if you put enough power through them). Hobby motors can get up to high RPMs when lightly loaded and fling random objects from the desk in random directions (that was my favoritest thing until I got caught). And that's just the unintentionally dangerous stuff I got up to in high school...

LEDs are mostly harmless. LEDs tend to be in elastic plastic packages with low melting temperatures, super-thin internal wiring, and usually they just change color, get dim, and then emit terrible-smelling smoke as they fail. The smoke might not be good for you, but I wouldn't expect a LED to injure your eyes unless you wired up a lot of them in one place and then stared at them.

As a rule, anyone who hasn't seen electronics go bad first hand will put their eyes a lot closer to a live circuit board than anyone who has. Some of your students will inevitably decide to lose the goggles if they experiment on their own outside of class, so your class should get them into the habit of aiming their circuit away from their face the first time they turn it on, in case something surprising happens (and don't look at it too closely while it's powered at any time, for that matter).

Watch out for capacitors! Electrolytic caps are designed to burst safely instead of exploding, but they aren't always successful, and there are even more dangerous things caps can do than explode. A 3000uF capacitor can release a lot of energy in a short time--enough to explosively heat the air inside a crowded breadboard and launch pointy metal parts in all directions, or cause ear injuries (the "bang" can be very very loud) or burns.

Think defensively: what if "you have 30 students" and "each one has a 1000uF filter capacitor on their breadboard" both happen on the same day? A student from my class decided to try connecting all the biggest caps he could find in the supply cupboard, charged their OMGcap with a 9V battery, then discharged it with a screwdriver to enjoy the spark. The energy discharge shattered the screwdriver tip. The OMGcap (and the student) were lucky and suffered only trivial injuries. School administrators did an audit of what was in that supply cupboard and how and when it was to be secured, but ultimately the problem came down to insufficient supervision and one student with just enough education to be dangerous.

The ARDX photo has what looks like a non-trivial electrolytic capacitor, but there are no details of such a component on the detailed description. I'd check to see if it's there when you get your kits, and only make it available during the lesson(s) that use it, before handing it out to a classroom of students from my class. ;)

In science class (not electronics class), lab classes involving electricity started with a written warning that any student caught assembling more than three AA batteries in any configuration during the class would face academic suspension on the spot.

There wasn't an injury disclaimer form for either class (I don't think it would have been a good legal idea anyway--teachers are generally encouraged to avoid situations where their students could reasonably expect to be injured during regular classroom activities).

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cccookie
 
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Re: Safety goggles in Arduino class?

Post by cccookie »

As someone who has 30+ years messing with circuits professionally and as a hobbyist, and having taught a few years of high school chemistry and physics...

Eye protection is a good idea from a liability standpoint, "just in case." Exploding parts? Not likely. Reality is going to be much more mundane ... a slim but not zero chance of wire bits coming off the diagonal cutters. Maybe a blown cap if someone is very off task. Yeah, I've done it a few times on purpose. Only happened to me once accidentally, and it mostly just filled the room with smelly white fog. As others have said, resistors and LEDs are somewhat ... ah, undramatic in their failure methods. Unless the kids start plugging into 120V. And even then...

Here's what you need to know. Goggles, AKA "splash resistant goggles" are for wet chemicals. They are hot, uncomfortable, fog up, and they leave marks on faces. Elastic straps mess up hair. Kids hate them. So do adults. Reserve the goggles for labs with hot or caustic liquids. What you are looking for are "impact resistant safety glasses with side shields." They come in plain, fancy, and nerd. Also tinted, clear, and mirrored. In a rainbow of colors.

Here are some funny, how not to do electronics videos: http://www.youtube.com/user/msadaghd?feature=watch

ScienceRules
 
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Re: Safety goggles in Arduino class?

Post by ScienceRules »

For safety glasses make sure they wrap around or have side panels and

have the ANSI Z87 designation somewhere on the glasses or Z87 with an extension number.

I have shot bb's at the Z87 glasses and the bb only makes a ding at a distance of 15 feet. (If you try this make sure you are wearing safety glasses because the bb's can bounce back at you.)

I have also shot bb's at "safety glasses" without the ANSI designation. The bbs make holes in the lenses of these glasses.

Be safe, Have fun!

brainfart
 
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Re: Safety goggles in Arduino class?

Post by brainfart »

May I also suggest full face shields with hard hat:

Image

cut resistant kevlar gloves worn under heat resistant BANNED welder gloves and of course full lenght BANNED BANNED to avoid solder induced gonad burns. Steel toe cap shoos (*) are a given, not necessary to mention them here explicitly.

If potentially toxic organic solvents like acetone or isopropanol are being used in class full faceshield respirators are of course unavoidable. Even though they are normal products of human metabolism they might or might not be known to cause cancer and liver damage in the foreseeable future, so you better cover your ass regarding litigation.


This really is ridiculous. Chaining more than 3 AA batteries will get you thrown out of class? What if I accidentially place two cr2032 batteries on top of each other? Event horizon collapse?

(*) = intentionally misspelled due to the automatic spam filter!LOL!

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