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Power consumption is one of the most critical system design parameters, particularly in the case of battery powered computer systems. This paper presents a novel method of data acquisition and processing suited for the dynamic power estimation of computer systems. It is the goal of the designer of these systems to maximize the useful system operation time with a fixed battery charge. In order to achieve the goal of maximum lifetime, several key data points about the real-time power consumption of the system are needed. These include average, maximum, and minimum current drawn over a period of time and also instantaneous current drawn by the system while it is active. We developed a separate power measurement device to provide the real-time data sets generated by the system under test. The power measurement device will determine the current drawn by the system under test, and will provide to the user the average, maximum, and minimum current drawn by the system during the period of the test. The power measurement device can also provide real-time current draw of the system under the test, within the precision of the power measurement device. We use a very low power microcontroller, Texas Instruments MSP430F149, for data acquisition and processing. We also provide a real-time data stream of average samples to the standard RS-232 serial communications port with the sampling frequency of approximately 6.9 kHz. Real-time traces of the dynamic power consumption collected by this power measurement device allow designers to modify hardware and software architecture to extend the system lifetime with a given battery charge.