PORTABLE INFORMATION DEVICE CONTROLLING RADIO TAG READING PART BY ELECTROMAGNETIC FIELD SENSOR OUTPUT, PROGRAM AND READING PART CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a portable information device that can use a radio tag mounted in the device and a reader writer therein respectively as needed without relying on a manual change-over operation.SOLUTION: The present portable information device provided with a radio tag part is configured to comprise: a radio tag reading part that reads information from an external radio tag; an electromagnetic field sensor that detects an external electromagnetic field; electromagnetic field determination means that determines whether an electromagnetic field formable by an external electromagnetic wave source driving the radio tag part is received or not using external electromagnetic field information output from the electromagnetic field sensor; and reading part control means that stops the radio tag reading part when the electromagnetic field determination means performs a true determination. With this configuration, the radio tag reading part is controlled to be stopped as needed when the radio tag reading part is likely to be close to an external reader writer.