Design of a microcontroller-based electronic pill counting device

This thesis covers the author's design and implementation of the electronics and software used to operate a microcontroller-based pill counter. Development was carried out in two phases. First, a personal computer was used to test the conceptual design. With some modifications to improve the device, a prototype was developed using the Motorola 68HC11EVB. This document describes the systems used to make up the pill counter including stepping motor drivers, photoelectric counters, keypad and LCD display. The theory behind the operation of the pill counter is to separate a bulk of pills into a single-file "stream" where they are counted using optical means. Separation of the pills is accomplished first by an augured drum, and second by a rotating cone platform. The drum serves as a reservoir for pills and when turning, slowly feeds pills onto the rotating cone, which carries them to an exit chute for counting. The 68HC11 microcontroller has many interesting features that are used to the benefit of the pill counter, and are described in this thesis. Software development followed modern software engineering techniques, specifically those of structured programming, that are described in this document. The motivational factors behind these techniques are also discussed.