Bosch Sensortec recently launched new generations of smart accelerometers and high performance gyroscopes intended for wearables, smartphones, and numerous other mobile devices. The new sensors integrate embedded intelligence functionality into standalone accelerometers, which enables innovative applications, while minimizing power consumption.
There are two new intelligent three-axis accelerometers: BMA422 and BMA455. Low current consumption extends battery life and the integrated Android 6.0 Marshmallow features simplify programming. Each device delivers outstanding accelerometer performance, low offset, low temperature coefficient offset (TCO), and low noise levels. The BMA422 accelerometer is ideally suited for standard applications. The BMA455 is intended for gaming and immersive activity-tracking.
The two new high-performance gyroscopes (BMG250 and BMG280) combine low noise, low TCO and high bias stability. They both feature low power consumption to extend battery life in mobile devices.
The BMA422 measures 2.0 × 2.0 × 0.95 mm³, while the BMA455 is 2.0 × 2.0 × 0.65 mm³. The BMG250 and BMG280 gyroscopes are both 3.0 × 2.5 × 0.83 mm³. Samples are now available.
Arduino is an open-source development kit with a cult following. Open source means the software and hardware design files are available for free download. This begs the question of how the Arduino team can turn a profit, and the answer is the trademark and reputation of the Arduino name and symbol.
While there are now many Arduino clones, the original Arduino boards still outperform most. Arduino is very useful for prototyping. A recent example in my own work is adding a gyroscope sensor to a project. First, I purchased a gyroscope board from Pololu for a small amount. I plugged it into an Arduino breadboard shield purchased from eBay for roughly $5, and wired up the four pins: VCC (3.3 V), GND, SCL, and SDA. Pololu’s website has a link to some demo firmware and I downloaded this from GitHub. The library folders were extracted and renamed according to the instructions and then the example was run. The Arduino serial monitor then showed the gyroscope data in real-time, and the entire process took no more than 30 minutes.
Editor’s note: This EE Tip was written by Fergus Dixon of Sydney, Australia. Dixon runs Electronic System Design, a website set up to promote easy to use and inexpensive development kits. The Arduino Uno pictured above is a small portion of a full Arduino blueprint poster available for free download here.
The NavRanger-OEM combines a 20,000 samples per second laser range finder with a nine-axis inertial measurement unit (IMU) on a single 3“ × 6“ (7.7 × 15.3 cm) circuit board. The board features I/O resources and processing capability for application-specific control solutions.
The NavRanger‘s laser range finder measures the time of flight of a short light pulse from an IR laser. The time to digital converter has a 65-ps resolution (i.e., approximately 1 cm). The Class 1M laser has a 10-ns pulse width, a 0.8 mW average power, and a 9° × 25° divergence without optics. The detector comprises an avalanche photo diode with a two-point variable-gain amplifier and variable threshold digitizer. These features enable a 10-cm × 10-cm piece of white paper to be detected at 30 m with a laser collimator and 25-mm receiver optics.
The range finder includes I/O to build a robot or scan a solution. The wide range 9-to-28-V input supply voltage enables operation in 12- and 24-V battery environments. The NavRanger‘s IMU is an InvenSense nine-axis MPU-9150, which combines an accelerometer, a gyroscope, and a magnetometer on one chip. A 32-bit Freescale ColdFire MCF52255 microcontroller provides the processing the power and additional I/O. USB and CAN buses provide the board’s high-speed interfaces. The board also has connectors and power to mount a Digi International XBee wireless module and a TTL GPS.
The board comes with embedded software and a client application that runs on a Windows PC or Mac OS X. It also includes modifiable source code for the embedded and client applications. The NavRanger-OEM costs $495.