A pen-based entry electronic device has a body having a holder portion for holding a pen that is carried along with the body and a keyboard having an engagement portion that engages with the holder portion. The heater has an operating temperature which is selectively maintained by applying a first voltage thereto, and the heater further has a maximum recommended temperature which is selectively maintained by applying a second voltage thereto. The semiconductor substrate is formed of silicon. Each controller is coupled to the respective individual radiation detector assemblies positioned at the two sides of the traffic way to which that controller is associated, such that two controllers associated with two adjacent traffic ways couple to the individual radiation detector assembly positioned between those two adjacent traffic ways.