The accelerometer
This breakout boad is a 3.3V powered module with selectable ranges (±1.5, 2, 4, and 6g). The MMA7260QT outputs an analog voltage for each of the three outputs. This voltage is in ratio to the measured acceleration and to the supply voltage. The built in Arduino’s ADC will convert this analog signal to a usable digital one. The output has a zero bias point around half of his supply voltage (1.65V). So the output voltage will be above the zero point for positive acceleration values and below it for negative ones.
Range selection
The GS1 and GS2 pins are used to configure the range according to the following table:
This means that if you want to be able to measure accelerations form -1.5g to 1.5g you need to connect GS1 and GS2 to ground, if the desired range is
Sleep
The breakout board provides a Sleep Mode function for a significant reduction of operating current. When Sleep Mode is active, the device outputs are turned off and the current is reduced to 3uA. By placing high input signal to the Sleep pin the device will resume to normal mode of operation (50uA).