If I were in the states and the FBI were to search my room I would certainly be held for questioning. I have electronics parts capable of making a detonator either remote or timed, I have some lab glassware that could be used to make explosives as well as a few (though small amounts) chemicals also used to make explosives. I also know how to and have made detonators before, for rocketry, a potato cannon, remote photography, and fireworks. I also have the lab knowledge and experience to make basic explosives from scratch. It is really quite simple if you know the chemistry. Plus I have access to large supplies of lab grade reagents and several tonnes of fertilizer. Basically, after posting this I will be watched be CSIS and the FBI.
I am not a terrorist though. Besides, the explosives I could make are much too unstable to use in a non-suicide bomb terrorist situation.
I mean all is takes to make a cell phone detonator is replacing the pager motor with a relay and soldering in an extra battery for longer up time. You could also double up the relays with a simple circuit holding one open as long as the power source is connected and tripping it if the cellphone loses power or is destroyed, obviously this would use a separate power supply. Anyways, redundant detonation systems aside you should never build an cellphone activator, even if it is a text activated light switch you use for turning on the porch lights when you get back, the police see a cellphone wired into the wall and threaten to call the bomb squad...
EDIT: That reminds me of a project I plan on doing that will make a computer text me when a motion sensor is tripped.
