A customer came to us with an idea to create a digital sports training device. The purpose of this device was to measure effectiveness as a function of speed attained while performing a certain exercise. Technical Support, Inc. had several challenges with this design. The first challenge to overcome involved the trainer. It incorporated a microcontroller and an accelerometer (a rather power hungry device) that had to run on two AA alkaline batteries for six months of normal use before the batteries needed to be replaced. This requirement led our engineers to create an ultra low power design. They decided that both hardware and software had to be optimized requiring the two engineers work very closely together (the norm at Technical Support, Inc.). We started by creating 5 volts using a switcher and then fed that to an LDO to get the necessary 3.3 volts for the microcontroller (TI MSP 430). We used A/D conversion in the MSP 430 to convert the sensor data into the readings on a small LCD. The microcontroller powers down the unit when it determines there is no more motion.
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