The little chip in the middle of the PCB is the actual MMA8451 sensor
that does all the motion sensing. We add all the extra
components you need to get started, and 'break out' all the other pins
you may want to connect to onto the PCB. For more details you can check
out the schematics in the Downloads page.
sensor on the breakout requires 3V power. Since many customers have 5V
microcontrollers like Arduino, we tossed a 3.3V regulator on the board.
Its ultra-low dropout so you can power it from 3.3V-5V just fine.
Vin - this is the power pin. Since the chip uses 3 VDC, we have
included a voltage regulator on board that will take 3-5VDC and safely
convert it down. To power the board, give it the same power as the logic
level of your microcontroller - e.g. for a 5V micro like Arduino, use
3Vo - this is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like
GND - common ground for power and logic