Photoelectric Sensors Offer Application Advantages

Pepperl+Fuchs ML4.2 Series Subminiature Photoelectric Sensors have faster response times, multi-beam redundant detection, independent outputs and zero deadband sensing. The newest ML4.2 high-speed models offer 250 µs response time, half the time of the standard ML4.2 models. ML4.2 dual sensor redundant detection models have dual light beams from two emitter LEDs that reflect light to two receivers.  Compared with single beam sensing, the redundant light beam enables more reliable sensing of transparent or glossy objects that are foil or plastic-wrapped.

For more information about Pepperl+Fuchs ML4.2 Series Subminiature Photoelectric Sensors, click here for high speed models or here for dual sensor redundant detection models.

Measuring with a 2D Optical Micrometer

Keyence calls its TM-3000 the world’s first in-line 2D optical micrometer. By combining the functionality of a laser scan micrometer, machine vision system and optical comparator into a single device, the sensor eliminates the need for expensive positioning mechanisms to ensure the best precision.

The 2D optical micrometer has a dual telecentric lens and a two-dimensional CMOS array. The dual lens creates a uniform collimated light with a green LED.  Then the CMOS array detects the light to dark transitions on the 2-D array to measure the dimensions. High speed and high precision result from sub-pixel processing only in the areas or points designated for measurement.

For more information on Keyence TM-3000 2D Dimensional Measurement System, click here.

Silicon MEMS Gyro Takes on Fiber Optic Gyros

Mechanical gyroscopes use a top-like mechanism spinning at high speed to detect angular position and provide high precision but at a high price. In contrast, fiber optic gyros (FOG) have minimal moving parts and offer high precision as well with a medium to high-end pricing. Sensonor Technologies’ STIM210 gyro module targets both designs with low bias error over temperature, a bias instability of 0.5⁰/h and low noise of 10⁰/√h. Operating over a temperature range of -40 to +85⁰C, the MEMS-based gyro is insensitive to magnetic fields and has no intrinsic wear-out mechanisms.

For more information about Sensonor Technologies’ STIM210 MEMS gyro module, click here.

Sensors Monitor Solar Power Conversion

The conversion of solar energy to electrical power is anything but uniform under varying weather conditions. To monitor several key system parameters, RainWise, a professional grade meteorological equipment manufacturer designed the PVmet Solar Energy Efficiency Monitor specifically for the photovoltaic (PV) industry. The unit can continuously measure key solar panel performance indicators such as ambient temperature, solar irradiance, plane-of-array irradiance, back-of-module temperature and wind speed and direction. This information allows accurate performance modeling, fault detection, and maintenance scheduling of solar equipment. The monitor is offered in three different models: entry (PVmet 100), intermediate (PVmet 200) and utility level (PVmet 300).

For more information on RainWise PVmet Solar Panel Monitors, click here.

Smallest Sensor Week: Dual-Axis Gyroscopes Boast Smallest Packaging

With a 3 x 3 x 0.75-mm form factor, InvenSense Inc. lays claim to the world’s smallest dual-axis gyroscopes. Targeting optical image stabilization (OIS) in smartphones, the IDG-2020 is an x-y (roll and pitch) and the IXZ-2020 is an x-z (roll and yaw) dual-axis MEMS gyroscope.

Features in the gyroscopes designed specifically for OIS requirements include the ability to have a factory full-scale output of ±32 degrees per second (dps) for the highest sensitivity to detect the slightest hand jitter, high-performance 32kHz ADC sampling, a nominal drive frequency of 27kHz that makes the gyroscopes immune to interference from audible frequencies such as music or ambient noise, a high speed 20-MHz SPI serial interface, and more.

For more information about InvenSense IDG-2020 and IXZ-2020 dual-axis gyroscopes, click here.

Smallest Sensor Week: Dual-Axis Digital Accelerometer Boasts Smallest Packaging

The second of this week’s small sensors is the world’s smallest and most robust digital accelerometer from MEMSIC Inc. Using patented MEMS thermal technology manufactured with a standard 0.18 µm CMOS process and advanced wafer- level packaging (WLP), the MXC6226XC two-axis digital accelerometer fits within a 1.2. x 1.7 x 1.0 mm package.  Per the company’s analysis, this makes it approximately 50% smaller than competitive products.

The two-axis digital accelerometer can measure acceleration over a ±2 g range with an absolute  0g offset of less than ±50 mg as well as can detect four orientation positions and provide shake detection. The company’s thermal accelerometer technology uses no moving internal structures, so the accelerometer exhibits extremely high shock survivability (up to 50,000g).

For more information on the MEMSIC MXC6226XC two-axis digital accelerometer,
click here.

Smallest Sensor Week: Smallest 3-Axis Digital Gyroscope

With microelectromechanical system (MEMS) technology and semiconductor packages, sensor manufacturers compete to cram the most technology into the smallest package. This week, Sensor Tips will highlight products that the manufacturer says is the world’s smallest. Without performing the extensive research necessary to verify the claims, we’ll take their word for it. Users can take advantage of these products’ minute size and capabilities to add features and performance to portable electronic products.

The first smallest sensor is STMicroelectronics world’s smallest 3-axis digital gyroscope. Housed in a 3 x 3.5 x 1-mm land grid array (LGA) 16-pin package, the L3G3200D gyroscope provides a 16-bit data output on the interrupt and data-ready lines and it integrates low- and high-pass filters with user-selectable bandwidth. The gyro operates with any supply voltage within the range of 2.4 to 3.6V with selectable full-scale values of ±250/500/2000 dps.

For more information about STMicroelectronics L3G3200D 3-axis digital gyroscope, click here.

Hydrogen Pressure Sensor for Fuel-Cell Vehicles

Fuel-cell vehicles are among the automotive industry’s research efforts to reduce the dependence on petroleum. Monitoring the high pressure in the hydrogen storage tank(s) for a minimum of 10 year life expectancy is just one of the challenges in bringing these vehicles to volume production. With it’s recently introduced AST 2000H2 Hydrogen ASIC Pressure Sensor, American Sensor Technologies thinks this is one problem area that has been solved. The sensor is already certified for use by European and Asian automobile manufacturers as on-board hydrogen sensors for fuel cell vehicles. Anticipated volume production for these vehicles will begin in the 2014/2015 timeframe.

Exposure to hydrogen can result in hydrogen embrittlement in metals, especially high strength steel. To reduce the chance of embrittlement caused by long-term exposure to hydrogen, AST 2000H2 sensors are constructed from a version of high strength 316L stainless steel wetted parts that promote long life and resistance to media corrosion. In addition, the company’s proprietary Krystal Bond Technology that utilizes inorganic bond, free from glue line failure and outgassing reduces long-term drift to just 0.25% per year.

For more information about American Sensor Technologies’ AST 2000H2 Hydrogen ASIC Pressure Sensor, click here.

Vibration Energy Harvester Powers Train Sensors

Trains provide a sustainable source of vibration energy to power sensors, at least while they are moving. Testing has shown that the vibration spectra generated by train wheels was sufficient to allow Perpetuum’s energy harvester to generate 10s of mW of electrical energy – a level sufficient to power sensors to monitor the condition of wheel bearings.

Optimized to deliver the highest power output from vibration frequencies between 30Hz – 60Hz that are typical to the rail industry, Perpetuum’s PMG Rail operates in the temperature range from -40°C to 85°C (-40°F to 185°F) and has factory programmed voltage outputs from 3V – 10V.

Other monitoring and sensing applications for the PMG RAIL products include:

- Bearing Monitoring

- GPS Location Tracking

- Hazardous Cargo Monitoring (Temperature, Pressure, “Door Open”)

- Wheel Condition Monitoring (Flats, Cracks)

- Derailment

- Braking System Monitoring

For more information about Perpetuum’s PMG RAIL products vibration energy harvesters, click here.

Sense Acceleration with a 2 x 2-mm Package

Sensing acceleration in a space-constrained end product may result in the tradeoff of another feature if the accelerometer takes too much space. To avoid the conflict, STMicroelectronics introduced three-axis accelerometers in 2×2 mm packages. The tiny sensors have a quite a few features
of their own.

With full-scale ranges of ±2g/±4g/±8g/±16g, the LIS2DH and LIS2DM accelerometers include 4D/6D orientation detection and two programmable interrupt signals for motion detection, free fall and other conditions. The sensors also incorporate power saving features to improve battery life in portable applications that include power-down and sleep modes and a FIFO (first-in first-out) memory block for smarter power management.

The difference between the two sensors is the LIS2DH has more programmable sensitivity adjustments, a typical zero-g offset accuracy of ±40 mg versus ±100 mg for the LIS2DM and higher self-test output capabilities.

For more information about STMicroelectronics LIS2DH and LIS2DM triaxial accelerometers, click LIS2DH or LIS2DM.