Analog Devices' MEMS Motion Sensor

“Motion sensing has become a desirable technology for a range of mobile products, as cell phones add pedometer functions for health-conscious consumers; phones and digital cameras adopt landscape-to-portrait and horizon-orientation photo features; and mobile entertainment devices integrate wrist movement, shaking, rolling and other actions into the interactive gaming experience,” said Bill Murphy, product line director, Micromachined Products Group, Analog Devices. “ADI’s newest iMEMS product addresses two important pain points in these areas by lowering the current consumption of the ADXL345 to as little as 25 microamps and increasing the resolution across the entire measurement range.”

The ADXL345 motion sensor incorporates an on-chip FIFO (first-in/first-out) memory block that stores up to 32 sample sets of X, Y, and Z data. By sampling input data to determine if the system should be actively responding to a change in movement or acceleration, the new motion sensing devices save additional system power by off-loading that function from the host processor. Typically, a host processor consumes a dominant amount of system power budget, so allowing it to remain in sleep mode as long as possible can dramatically decrease overall power usage upwards of 75% of the budget, when utilized effectively.