Abstract: The invention relates to a writing pen with a liquid crystal screen displaying the tested alcohol concentration value, and its architecture includes a lower barrel, an upper barrel, and a sensor device. The sensor device has a circuit board, wherein a sensor, a liquid crystal screen, and a processing unit are installed on and electrically connected to the circuit board. The circuit board receives the alcohol content in the user's exhaled breath and converts it so that a precise value can be displayed on the liquid crystal screen. Hence, a writing pen that can be readily carried and has a liquid crystal screen displaying the tested alcohol concentration value is completed.

Abstract: A composite pen coupled with an earphone for a mobile phone (4) includes a pen (1) and a chamber (2) located at one end of the pen that has a circuit board (3) disposed therein. The Circuit board (3) connects to an output unit (34), an input unit (35) and a connector (36). The connector (36) may plug in the mobile phone (4) for the output unit (34) to broadcast the audio sound from the mobile phone (4) and the input unit (35) to receive verbal voice from the user. The composite pen thus has both writing and earphone capability.

Abstract: A composite alcohol testing pen includes a lower barrel (1), an upper barrel (2) and a gas detection device (3) The upper barrel (2) has a switch (21) and a light emitting diode (2) located at the outer surface, and a circuit board (4) and a battery (7) located inside. The circuit board (4) has an analyzing unit for analyzing alcohol concentration. The gas detection unit (3) receives breathing air from an users and detects the alcohol concentration contained therein.