1. Fighting fire with fire. Most piezeoelectric tweeaters
will happily generate sound well over 15,000 Hz which is
near my hearing cutoff. With an amp, a cheap mp3 source,
and a suitable speaker, you can annoy the heck out of your
students. Suggest that you will keep it playing
continuously if you find out that students are using the
ring tone. Let peer pressure do your dirty work.
2. Detecting incoming signals. If you run an unshielded
cord around the room, you will detect the "I am here"
signal from a cell phone. I did this unintentionally in a
lab, and the results were kind of cool. There were six lab
stations each using a Pasco Xplorer as a signal generator
connected via an unshielded headphone cable to a small amp
and speaker. A student in the lab group had his cell phone
on and the resulting bzzt noise on that group's speaker
gave his group away. Explaining why a gigahertz signal is
detectable this way is more of a challenge.
3. Jamming the signal. Illegal and hard to do, but wouldn't
it be cool?
4. Installing a Faraday Cage. This is really hard to do
these days as cellphones have impressive signal boosting
abilities, but sometimes it is only a small part of the
room that is letting in enough signal to make a difference.
A well placed piece of aluminum foil can make your day.
5. Changing school policy. Our school initially had the
rule that cellphones could only be used before and after
school. However, when the rule changed that they could also
be used in between classes, the amount of use in classes
went down.
6. Remembering that students have always found ways not to
pay attention. I didn't have a cellphone, but I had a
paperback that I tried to discretely read during classes I
thought were dull. Or looking out the window, passing
notes, etc. No system will work all the time, and it is
probably good that they don't. It is a student's
responsibility to test limits and it is our responsibility
to punish them when they go over the line.
Marc "Zeke" Kossover
...who really remembers nothing from most of his English classes.