This board is a compact (0.5? × 0.9?) breakout board for ST’s L3GD20 three-axis digital-output gyroscope; we therefore recommend careful reading of the L3GD20 datasheet (2MB pdf) before using this product. The L3GD20 is a great IC, but its small, leadless, LGA package makes it difficult for the typical student or hobbyist to use. It also operates at voltages below 3.6 V, which can make interfacing difficult for microcontrollers operating at 5 V. This carrier board addresses these issues by incorporating additional electronics, including a 3.3 V voltage regulator and level-shifting circuits, while keeping the overall size as compact as possible. The board ships fully populated with its SMD components, including the L3GD20, as shown in the product picture.
Compared to the older L3G4200D, the L3GD20 uses a higher resonant frequency that makes it more resistant to audio noise and vibrations. This board remains pin-compatible with the original L3G4200D carrier, although changes in I²C addresses and configuration registers mean that code written to interface with an L3G4200D might need to be modified to work with an L3GD20.
The L3GD20 has many configurable options, including three selectable angular rate sensitivities, a choice of output data rates, an embedded FIFO for buffering output data, and a programmable external interrupt signal. The three angular velocity readings are available through a digital interface, which can be configured to operate in either I²C or SPI mode.
The carrier board includes a low-dropout linear voltage regulator that provides the 3.3 V required by the L3GD20, which allows the sensor to be powered from a 2.5-5.5 V supply. The regulator output is available on the VDD pin and can supply almost 150 mA to external devices. The breakout board also includes a circuit that shifts the I²C/SPI clock and data in lines to the same logic voltage level as the supplied VIN, making it simple to interface the board with 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 L3GD20Hwith an LSM303D 3-axis accelerometer and 3-axis magnetometer 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: 0.7 g (0.03 oz)
- Operating voltage: 2.5 to 5.5 V
- Supply current: 7 mA
- Output format (I²C/SPI): one 16-bit reading per axis
- Sensitivity range (configurable): ±250°/s, ±500°/s, or ±2000°/s
A 9×1 strip of 0.1? header pins and a 9×1 strip of 0.1? right-angle header pins are included, as shown in the picture below. You can solder the header strip of your choice to the board for use with custom cables or solderless breadboards, or you can solder wires directly to the board itself for more compact installations.