LSM303DLM 3D Compass and Accelerometer Carrier with Voltage Regulators
The LSM303DLM combines a digital 3-axis accelerometer and 3-axis magnetometer into a single package that is ideal for making a tilt-compensated compass. The six independent readings, whose sensitivities can be set in the ranges of ±2 to ±8 g and ±1.3 to ±8.1 gauss, are available through an I²C interface. The carrier board operates from 2.6 to 5.5 V and has a 0.1″ pin spacing.
This board is a compact (0.5" × 0.9") breakout board for ST’s LSM303DLM 3-axis accelerometer and 3-axis magnetometer. The LSM303DLM is a great IC, but its small package makes it difficult for the typical student or hobbyist to use. The device also requires multiple voltage supplies not typically available when interfacing with 3.3 or 5 V systems. This carrier board addresses these issues by incorporating additional electronics, including two voltage regulators and a level-shifting circuit, while keeping the overall size as compact as possible. The board ships fully populated with its SMD components, including the LSM303DLM, as shown in the product picture.
The LSM303DLM has many configurable options, including dynamically selectable sensitivities for the accelerometer and magnetometer, a choice of output data rates, and two independently-programmable external inertial interrupt pins. The magnetometer and accelerometer can be individually turned on and off to save power, and a special sleep-to-wakeup function allows the accelerometer to sleep until an inertial interrupt is triggered. The six independent magnetic and acceleration readings (sometimes called 6DOF) are available through an I²C/TWI interface and can be used for many applications, including making a tilt-compensated compass that can be used to determine headings regardless of how the board is inclined (ST provides an application note that explains the details of making one).
The carrier board includes two voltage regulators that provide the 1.8 V and 3 V required by the LSM303DLM, which allows the sensor to be powered from a single 2.6 – 5.5 V supply. The regulator outputs are available on the 1V8 and 3V pins and can supply almost 150 mA and 300 mA, respectively, to external devices. The breakout board also includes a circuit that shifts the I²C clock and data lines to the same logic voltage level as the supplied VIN, making it simple to interface the board with 3.3 V or 5 V systems, and the board’s 0.1" pin spacing makes it easy to use with standard solderless breadboards and 0.1" perfboards.
For sensor fusion applications, our MinIMU-9 v3 and AltIMU-10 v4 inertial measurement units combine the similar LSM303D accelerometer/magnetometer with an L3GD20H 3-axis gyro on a single board, providing nine independent readings that can be used to calculate an absolute orientation. The AltIMU-10 v4 also includes an LPS25H pressure sensor that can be used to calculate altitude.
- Dimensions: 0.5" × 0.9" × 0.1" (13 × 23 × 3 mm)
- Weight without header pins: 0.84 g (0.03 oz)
- Operating voltage: 2.6 to 5.5 V
- Supply current: 10 mA
- Output format (I2C):
- Accelerometer: one 12-bit reading (left-justified) per axis
- Magnetometer: one 12-bit reading (right-justified) per axis
- Sensitivity range (configurable):
- Accelerometer: ±2, ±4, or ±8 g
- Magnetometer: ±1.3, ±1.9, ±2.5, ±4.0, ±4.7, ±5.6, or ±8.1 gauss