7 pages/≈1925 words
Health, Medicine, Nursing
The MEMS Motion Sensor Three-Axis Digital Output Gyroscope (Lab Report Sample)
In my report, I am discussing about the MEMS motion sensor three-axis digital output gyroscope. My device of discussion is from STMicroelectricals with a manufacturer part of A3G4250D. MEMS (Micro-electromechanical systems), is a technology that links computers to tiny mechanical devices embedded in semiconductor chips that senses and gives a report on the environmental properties and enable it to interact and actuate responses to the environment. MEMS are divided into two categories, sensors that gather information from the surrounding and actuators that execute given commands due to highly controlled movement. A gyroscope is a device that rotates on an axis on vibration. When vibration occurs, change in direction can be sensed thus used for sensory purposes. They have various applications in numerous fields that make them a part of everyday life. Among these include racing cars, motor bikes Segway scooters and monorail train. They act as stabilizers in most of these machines to indicate and prevent rolling due to shifts in speed, center of gravity, angular momentum or direction. Aircraft rely heavily on gyroscope on determining the position of a plane. Modern technology like computer hardware for pointing, virtual reality positioning as well as gyroscopic compasses borrow so much from this technology.
MEMS devices have a vast application in our day to day life as it enables the reliability of machinery like gyroscopes, optical and pressure devices, accelerometer and even chemical, biomedical and fluidic applications. They are used for their sole purpose of sensing, controlling and actuating actions to generate effects on the specific micro-scale impact and are dependent on their electronic and mechanical aspects for their reliability. This enables the automation of the functioning of most devices that cannot rely on the estimation of human resource. The sheer accuracy of the device revolutionized the various fields in which the gyroscope finds application.
The historical background of MEMS takes us back in the 19th century where Leon Foucault explored two types of angle measuring mechanical gyroscope that were either based on spinning or vibrating. Spinning gyroscope became dominant at the moment but was not a preference for MEMS this is because of technological limitation in manufacturing precisions and also its low friction bearing. In the market, it did not succeed due to its mechanical system instability and also the need for a sophisticated control system. The vibrating gyroscope was a mystery over the centuries until the early 20th century when Sperry introduced the first vibrating gyroscope which then laid the ground for more innovation of vibrating gyroscope-like tuning fork gyroscope by BEI Technologies in the late 20th century and the development of a silicon MEM CVG in the early 21st century that still reigns in the market today. The theoretical ingenuity of the pioneers was yet to match the mechanical advances of the time. However, with time, the gyroscope has been perfected to be a reliable, not to mention irreplaceable, instrument of measurement and safety. This has seen the gyroscope find application in various fields with proper understanding of the science behind it.
As discussed earlier in the history of MEMS devices, we clearly see that the pioneer scholar in discovering the gyroscope technology was Leon Foucault; later on, Sperry followed then the BEI Technologies and finally the silicon MEMS founder.
Gyroscopes are based on Coriolis Effect or precision principle. The diagrams below show the mechanicals of Coriolis Effect in gyroscopes. Mass m, is supported by two springs and dampers. Assuming; x-axis is the driving direction while y-axis is the sensory direction, when mass m, vibrates uniformly, the displacement along the x-axis will be expressed in the following equation: x (t) = Axcos (Ï‰xt)
"Where Ax is the amplitude, Ï‰x is the driving angular frequency.
Where an angular rate Î©z input rotating around the z-axis, it will cause Coriolis acceleration along y-axis: ay = 2Î©z Ã— dx/dt = â€’2Î©z AxÏ‰x sin (Ï‰xt). The angular rate can be calculated by detecting the y-axis displacement" (Xia, Yu and Kong 2012).
For optimum sensitivity and bandwidth, the sense mode and drive mode should be equal where the amplitude along the y-axis is at its maximum while bandwidth is minimal.
Motivation for the Current Work
The use of MEM devices is growing thus the need to study and understand the current technology that we have and get to know where the future of the technology is headed. Some of the inventions predicted or "under construction" are like the disposable chips blood and tissue samples, optical switching, and remote sensing products. The inventions are making the day to day life easier and not forgetting to give credit to the pioneers who started this technology and also the current innovators. By all means, the current generation should be involved in the revolution by making them aware of the technology present and the benefits in our life so as to nurture an innovative soul to join in the movement. It is important to teach this content in school to make students get familiar with the technological world we are living in that is evolving day by day. Knowledge of the workings of everyday items that blend into the life of the modern human being is scarce, and thus, stemming out this ignorance with the bit-by-bit comprehension of the ignored modern piling up on the modern man will give insight to ways in which the society can improve or redirect its attention.
The driving force to carry out this work is mainly to create awareness of the technology. With all the technology we live on and depend on, it is apparent that the current generation is totally dependent on technology. Thus, there is the necessity to get the knowledge required to keep the technological world grow but not killing the development which will be disastrous. This is commendable for the improvement of the condition of life with new research as well as finding better alternatives to everyday problems.
In my report analysis, I had to research on how the MEMS gyroscope works and get to see the different types in the market and chose the MEMS motion sensor three-axis digital output gyroscope to research on it. My sources were majorly online research and also studying the device. On online searches, I used journals, scholarly articles and websites. The requirements were to make an online order for the device, put it to test, open up the MEMS device to expose the internal device, give a picture of the device and if possible when opened up.
I have given the principles of gyroscope calculations done to determine the extent of vibration displacement along the x-axis and y-axis along the rotating axis of the oscillating objects. It is a necessary basic that is crucial in the understanding of the device parameters.
A split up of the A3G4250D MEMS gyroscope
My choice of device, the A3G4250D MEMS motion sensor three-axis digital output gyroscope, has the following properties directly retrieved from the website (A3G4250D ):
"Wide supply voltage: 2.4 V to 3.6 V, Â±245 dps full scale, I2C/SPI digital output interface, 16-bit rate value data output, 8-bit temperature data output, two digital output lines (interrupt and data ready), integrated low and high-pass filters with user selectable bandwidth, ultra-stable over temperature and time, low-voltage-compatible IOs (1.8 V), embedded power-down and sleep mode, embedded temperature sensor, embedded FIFO, high shock survivability, extended operating temperature range (-40 Â°C to +85 Â°C), ECOPACKÂ® RoHS and "Green" compliant and AEC-Q100 qualification" as per the STMicroelectricals website." (STMicroelectronics)
9906002171700Figure SEQ Figure \* ARABIC 3Figure SEQ Figure \* ARABIC 3176212560960A diagram of A3G4250D MEMS motion sensor three-axis digital output gyroscope
Discussion of Results
As we have seen from above, a MEMS device works on the basis of sensory and drive mode where it acts for safety purposes letâ€™s say for gyroscope whose application is mostly in automotive airbag where, when a high strength impact hits the car, the airbag pops out to safeguard the people at the front seats from injuries by the impact. This mechanism uses the A3G4250D MEMS gyroscope. This and many other forms of application like in the smartphone which makes it detect motion making the screen rotate, also its use in the medical field where it is used in the device that measures blood pressure, also in the industrial field, most appliances and robotics and many other aspects of life that it has a great impact of improvement in our live making work way easier. The theory behind the workings of the device makes it an impeccable addition to the functioning of num...
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