On Thu, 18 Apr 2013 00:01:27 -0500, aasberry wrote:

Speculation is that the bombs were set off by cell phone. I wonder if a
cell signal would penetrate the metal of a pressure cooker. Mine barely
works in my metal shop building; with the doors open. Any experts want
to weigh in?

Tape the phone to the outside of the pot, run the trigger wire inside.

I heard that kitchen timers were used -- they'd be a lot easier and
cheaper to set up, and harder to trace (if the bomber cared). Cell
phones would possibly me more satisfying to the profoundly sick sort of
mind that would do such a thing.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com