This tiny three-axis accelerometer is a breakout board for Freescale's MMA7361L MEMS (micro-electro-mechanical systems) low-g accelerometers. The MMA7361 is a great IC, but its small, leadless packages makes it difficult for the typical student or hobbyist to use. This carrier board includes all of the components in the part's recommended connection diagram and breaks the pins out to a 0.5 x 0.4in. 10-pin DIP form factor that is easy to use with standard solderless breadboards and 0.1" perfboards.

The board is powered by supplying 2.2 to 3.6 V on the VDD pin. Note that this part does not have 5V-tolerant pins, so external components (such as voltage dividers) are required when interfacing the board's g-Select, Self Test, and Sleep pins with 5V systems. Connections to these pins are optional; the board will work with these pins disconnected as long as the sleep pin is driven high with an on-board solder bridge as described below.

The sleep pin, Sleep, is internally pulled low, which puts the board into low-power sleep mode by default. You must drive this pin high to use the board. This can be accomplished with a microcontroller I/O line if you want selective control of sleep mode, or you can make a solder bridge across the SMT jumper pads labeled "ON" on the silkscreen side of the board to connect the sleep pin to VDD and enable the board by default.

The accelerometer X, Y, and Z outputs are three separate analog voltages centered at VDD/2. Positive accelerations along an axis increase that axis’s output voltage above VDD/2 and negative accelerations decrease the output voltage below VDD/2. The outputs will always be within the range of 0 to VDD.

The sensitivity selection pin, g-Select, is internally pulled low, which selects for a default sensitivity of ±1.5g (800 mV/g) on the MMA7361L carrier. Driving the pin high selects for a sensitivity of ±6g (206 mV/g) on the MMA7361L carrier.

The 0g-Detect pin outputs high when all three MMA7361L axes simultaneously detect 0g, which happens when the board is in free-fall. This pin only functions on the more sensitive MMA7361L carrier.

The Self Test pin is pulled low on the board and can be left disconnected.

Technical Data