Small size, low weight and rugged environmental specifications characterize embedded systems. PC/104 is an embedded system architecture that implements the compact version of the PC (ISA and PCI) buses. The PC/104 architecture uses 104 pins for stacking different boards and eliminates the need for card edges and backplanes. Standardizing hardware and software around PC architecture substantially reduces the development cost, time and risks involved. The purpose of this study is to develop an environmentally rugged and portable instrument based on the PC/104 architecture for measuring and recording voltage sags as per the International Electrotechnical Commission (IEC) standards 61000-4-30 and 61000-2-8. Two different central processing units (CPU) for the instrument are evaluated in terms of hardware setup, cost and performance. The overall performance of the instrument using either CPU indicates that the instrument can be reliably used to measure voltage sags.