Smartphone Application with an Ultrasonic Sensor for Measuring and Recording Distance in Crime Scene Investigation

Abstract

During a crime scene investigation, the distance measurement along with documentation of the distance data is an important procedure that significantly affects a crime reconstruction. The researcher developed a smartphone application that works with an ultrasonic sensor, namely, Crime scene distance measure and record application, with an aim to facilitate the measurement process and data recording. The application controls the operation of the ultrasonic sensor, save measurement data and create a document file according to the standard form of the Royal Thai Police. The distance measurement was tested at a simulated scene. The result showed that the accuracy and precision of the application were comparable to a laser meter. The error of distance was ±7 centimeters with a variable coefficient up to 13.4% and 13.9% for the application and the laser meter, respectively. For satisfaction assessment towards the application, it was tested by 20 police officers who are currently on duty of crime scene investigation. The results showed that the application was gained a good (56.50%) and very good (36.53%) satisfaction in terms of the user interface design, device features and functions, data storage and data retrieval as well as the hardware. This suggests the possibility to apply the developed smartphone application combined with an ultrasonic sensor for distance measurement in forensic practice.