隱約聽著 Mrphs 繼續說道︰這湖心小築裡有六個『學園』 Campus 是為小學堂暑修寒訓之『學習營』而預備。湖心平台上的是『天文 ‧氣象營』，其餘往下數，『科技營』在二十五層，『人文營』位於五十層，『海洋營』居七十五層，『地理營』佔第一百層。其實還有一個『生命館』屬於全體谷民，就設立於入口大廳。這個大廳的格局象個『  』田字，分有東南西北四館。其中東西北三館是『水』的三相 ── 水‧溼‧冰 ── 之展示館。這南館最特別，是『模擬』館，內有百座『計算單位』所構成的 It 網『平行運算器』 。所謂一個『計算單位』是由萬台『碼訊』machine 所集成。可以即時動態計算巨量的『非線性』方程式之『數值分析』，用以演示`『光』、『水』、『氣』交互系統之各種現象變化。傳達『生命』可貴的『科技護生』之旨。也是『學園』教與習『理化模型』使用的主機。……

只覺得腦海內哄鳴作響，想到曾以

《觀水》 ───

宋朝的邵康節號安樂先生，居地叫做『安樂窩』，著有『皇極經世』一書，將歷史紀年『卦象化』說能推知數百千年的現象；傳聞又有『梅花心易』一本，專講『見機』起卦之法，其中用著『京房八宮卦』，論斷之準真真神乎其技！！歷史上『科學』雖與『巫術 』有千絲萬縷的關聯，當細思

子不語：怪、力、亂、神。

季路問事鬼神。子曰：未能事人，焉能事鬼？敢問死？曰：末知生，焉知死？

；然而【易繫辭】裡卻又有

易與天地準，故能彌綸天地之道。仰以觀於天文，俯於察於地理。是故知幽明之故。原始反終，故知死生之說。是故君子所居而安者，易之序也，所樂而玩者，爻之辭也。是故居則觀其象，而玩其辭，動則觀其變而玩其占，是以自天佑之，吉無不利。

這個『死生之說』怎麼說？這是從大自然一年四季的循環，草木的一歲一枯榮，『原始反終』推論而知，絲毫沒有『迷信』的色彩。最後藉著『京房上飛下飛』觀『坎水』之死生之說，以饗讀者︰

京房『心要』︰自初至五不動復，下飛四往伏用飛，上飛下飛復本體，便是十六變卦例。

坎為水	☵ ☵	主卦	十六變還原︰再下飛二爻
水澤節	☵ ☱	一爻變
水雷屯	☵ ☳	二爻變
水火既濟	☵ ☲	三爻變
澤火革	☱ ☲	四爻變
雷火豐	☳ ☲	五爻變
地火明夷	☷ ☲	遊魂卦	不變宗廟，下飛四往
地雷復	☷ ☳	外在卦	下飛三爻
地澤臨	☷ ☱	內在卦	下飛二爻
地水師	☷ ☵	歸魂卦	下飛初爻
坤為地	☷ ☷	絕命卦	上飛二爻
地山謙	☷ ☶	血脈卦	上飛三爻
雷山小過	☳ ☶	肌肉卦	再上飛四爻
澤山咸	☱ ☶	骸骨卦	再上飛五爻
水山蹇	☵ ☶	棺槨卦	再下飛四爻
水地比	☵ ☷	墓庫卦	再下飛三爻

───

 

之『坎水』之死生之說，寓寫

《【Sonic π】電路學之補充《四》無窮小算術‧上》

一系列七上八下的文本，實以為『算術』何時成了學習『科學』的障礙！而今看來或許可以用計算機另闢蹊徑乎？不知有了個人超級電腦，再假以『體驗式』的環境，是否人們就能解決

《水的生命！！上》

假使從『十進制』的『無窮小數』 的觀點來看，所有的『有理數』 ，如果不是『有限小數』，就一定是『循環小數』。這是因為 的餘數只能是 ，既然說這個『除法』不是『有限的 』步驟，也就是說其間不能夠『整除』 ── 餘數為零 ──，那麼不超過 次，終究會出現『第一次』相同的『餘數』，此時『接續』的除法自然開始『重複』，所以必然就是『循環小數』的了！或許『循環』也可以看成有『周期性』出現的吧！！反過來說一個『循環小數』也一定能夠表示成『有理數』， 假有我們將 乘上 就可以得到 ，然而 已是『整數』，故可以不必考慮。假設 是那個『循環小數』 的部分，那麼 ，因此 ，於是 。所以從 ，可以得到 這個『有理數』的啊！！

如果我們換用『物理量』 的『量測觀點』來講 ，此處的 是『測量』可能引發的『誤差值』。假使 與 都可以表現為『有理數』，假設 ，此處 是一個『很大』的整數，那麼它的『最小誤差』也得是 ，這是因為『整數』 的『離散性』不得不導致的結論， 的『前一數』和『後一數』只能是 。

一八七四年『坎特爾』 Cantor 證明了『所有代數數』所構成的『集合』，也是『可數的』無限大。這有什麼重要的嗎？如果再次細思『劉維爾定理』

如果『無理數』 是一個 次『多項式』之根的『代數數』，那麼存在一個『實數』 ，對於所有的『有理數』 都有 。

。這是說對一個『代數數』 的『無理數』來講，它與『有理數』 的『距離』也許可以說『更遠』或者講『更近』 。然而假使 的話，，其實這也就是『無窮小』和『無限大』要如何議論『等級』的『問題』的啊！這樣說的話，當『實數』 去掉了『有理數』 ，再去掉了『代數數』 ，這個 的集合怎又可能是『可數的』呢？就算是『不可數』也怕會是『坑坑洞洞』的吧！！因此講那個『處處連續』、『無處可微分』以及『咫尺即天涯』之用實數『極限』的『科赫雪花』，恐怕是講著『分析』或也許說『解析』的『複雜』與『困難』代表的了！終將人們帶進了『撲朔迷離』的境遇的吧！就像是為甚麽又會有『邏輯必然』，但卻是『理解困難』的事情呢？？

───

 

中所講的『理解困難』耶？？！！

※ 杜鵑方才過，秋雷卻不收，徒留『春雷早發』之者！！

因為『 SD 卡相容性的問題』，走進了《 Debian Jessie on Raspberry Pi 2 》的森林，原以為『不能用的』，才拿『測試過的不能用的』來試，竟然……，

…

夫復何必哉？？

 

 

 

 

 

 

 

 

在繼續探討之前，就讓我們編集一下維基百科有關『大氣壓力』的若干詞條，以期對它有一些初步的認識︰

───

氣壓的國際單位制是帕斯卡（或簡稱帕，符號是Pa），泛指是氣體對某一點施加的流體靜力壓強，來源是大氣層中空氣的重力，即為單位面積上的大氣壓力。在一般氣象學中人們用千帕斯卡（KPa）、或使用百帕（hPa）作為單位。測量氣壓的儀器叫氣壓表。其它的常用單位分別是：巴（bar，1bar=100,000 帕）和公分水銀柱（或稱公分汞柱）。在海平面的平均氣壓約為 101.325 千帕斯卡（76 公分水銀柱），這個值也被稱為標準大氣壓。另外，在化學計算中，氣壓的國際單位是「atm」。一個標準大氣壓即是1atm。1個標準大氣壓等於 101325 帕，1.01325 巴，或者 76 公分水銀柱。

氣壓的地區差別是氣象變化的直接原因之一。氣壓是天氣預報的一個重要的變量。

在地球上，其來源是大氣層中空氣的重力，一般正常的空氣壓力 1kg/cm²。在高處之上的大氣層比較薄，那裡的空氣重力比低處要小，因此在高處的氣壓比在低處要低。比如在高山上氣壓比在海平面上要低。

───

Pressure varies smoothly from the Earth’s surface to the top of the mesosphere. Although the pressure changes with the weather, NASA has averaged the conditions for all parts of the earth year-round. As altitude increases, atmospheric pressure decreases. One can calculate the atmospheric pressure at a given altitude.^[6] Temperature and humidity also affect the atmospheric pressure, and it is necessary to know these to compute an accurate figure. The graph at right was developed for a temperature of 15 °C and a relative humidity of 0%.

 

At low altitudes above the sea level, the pressure decreases by about 1.2 kPa for every 100 meters. For higher altitudes within the troposphere, the following equation (the barometric formula) relates atmospheric pressure p to altitude h

where the constant parameters are as described below:

Parameter	Description	Value
p0	sea level standard atmospheric pressure	101325 Pa
L	temperature lapse rate, = g/cp for dry air	0.0065 K/m
cp	constant pressure specific heat	~ 1007 J/(kg•K)
T0	sea level standard temperature	288.15 K
g	Earth-surface gravitational acceleration	9.80665 m/s2
M	molar mass of dry air	0.0289644 kg/mol
R	universal gas constant	8.31447 J/(mol•K)

───

 

依據『壓力』的物理定義是『單位面積所受的正向力』 ，

維基百科中講︰

Pressure is the amount of force acting per unit area. The symbol of pressure is p or P.^[b][1]

Formula

Mathematically:

where:

is the pressure,

is the normal force,

is the area of the surface on contact.

Pressure is a scalar quantity. It relates the vector surface element (a vector normal to the surface) with the normal force acting on it. The pressure is the scalar proportionality constant that relates the two normal vectors:

The minus sign comes from the fact that the force is considered towards the surface element, while the normal vector points outward.

It is incorrect (although rather usual) to say “the pressure is directed in such or such direction”. The pressure, as a scalar, has no direction. The force given by the previous relationship to the quantity has a direction, but the pressure does not. If we change the orientation of the surface element, the direction of the normal force changes accordingly, but the pressure remains the same.

Pressure is transmitted to solid boundaries or across arbitrary sections of fluid normal to these boundaries or sections at every point. It is a fundamental parameter in thermodynamics, and it is conjugate to volume.

 

聽來如此簡單明白，然而若問五公里外流動不拘的空氣，為何能夠產生『壓力』的呢？有人說從『理想氣體狀態方程式』之推導可以知道

    空氣分子隨機碰撞

 

，產生了那個『壓力』，而且所謂的『力』由『牛頓運動定律』可表達為 ，即有『動量變化』就是發生『作用力』的另一種描述。然而一般那個

理想氣體狀態方程式的推導

；

其中， 為理想氣體的壓強， 為理想氣體的體積， 為氣體物質的量， 為理想氣體的熱力學溫度， 為理想氣體常數。

並不考慮『重力』，同時還有許多『理想假設』。如是在『微觀』上將如何說明『大氣壓力』的呢？首先『壓力』是『純量』沒有『方向性』，這就意味著各方向的『力向量』應當是『均等的』，也可以說大氣分子數量很大，『統計起伏』 Statistical fluctuations 很小。比方說，居兩、三千公里外的『散逸層』，大約每粒方公分只有『一個』氣體分子，在此處談『氣體壓力』又該怎麼講的呢？怕是沒有什麼意思的吧！其次地表『大氣壓力』隨著高度遞減，按『牛頓運動定律』來講，這個方向的『作用力』也是遞減的，它和『重力』方向相同，難道會違背『動能‧位能』的『守恆律』嗎？

要是再考之以『高度之溫度變化』

 

可知大氣現象極其複雜的了。或知為什麼在『氣壓感測器』裡也有『溫度感測器』耶？或可解釋『讀取值』變動的原因嗎？？

單只有『量測數據』，若是缺乏度量之『環境條件』，那個數值的『物理意義 』恐是難明難了的吧！！

 

 

 

 

 

 

 

 

 

 

假使我們閱讀

LPS25H 的『數據表』 Data Sheet ︰

Description

The LPS25H is an ultra compact absolute piezoresistive pressure sensor. It includes a monolithic sensing element and an IC interface
able to take the information from the sensing element and to provide a digital signal to the external world.

The sensing element consists of a suspended membrane realized inside a single mono-silicon substrate. It is capable to detect the absolute pressure and is manufactured with a dedicated process developed by ST.

The membrane is very small compared to the traditionally built silicon micromachined membranes. Membrane breakage is prevented
by an intrinsic mechanical stopper.

The IC interface is manufactured using a standard CMOS process that allows a high level of integration to design a dedicated circuit which is trimmed to better match the sensing element
characteristics.

The LPS25H is available in a cavity holed LGA package (HCLGA). It is guaranteed to operate over a temperature range extending from -30 °C to +105 °C. The package is holed to allow external pressure to reach the sensing element.

 

，或好奇於『壓阻效應』 Piezoresistive effect

壓阻效應是用來描述材料在受到機械式應力下所產生的電阻變化。不同於壓電效應，壓阻效應只產生阻抗變化，並不會產生電荷。

要如何用來量測『大氣壓力』？也許引用一段圖文將能解惑的耶！

 

8.4.5 Pressure Microsensors

Pressure microsensors were the first type of silicon micromachined sensors to be developed in the late 1950s and early 1960s.  Consequently, the pressure microsensors represent probably the most mature silicon micromechanical device with widespread commercial availability today.  ……

Figure 8.27 Basic types of silicon pressure sensors based on a vertical deflection: (a) piezoresistive (polysilicon) and (b) capacitive (single-crystal silicon)

The two most common methods to fabricate pressure microsensors are bulk and surface micromachining of polysilicon. Silicon diaphragms can be made using either technique as described earlier. Figure 8.27 illustrates the basic principles of a piezoresistive sensor
and a capacitive pressure sensor.

The deflection in the diaphragm can be measured using piezoresistive strain gauges located in the appropriate region of maximum strain, as shown in Figure 8.27(a). The strain gauges are usually made from doped silicon and are designed in pairs with a read-out circuit such as a Wheatstone bridge. The change in strain can be related to the applied pressure ( ) and stored in a lookup table. The precise relationship depends on the relevant piezoresistive coefficient of the diaphragm material.

     (8.32)

A single crystal of silicon is a desirable material to use for the diaphragm because neither creep nor hysteresis occurs. The piezoresistive constant ( ) is typically +138.1 pC/N
and that makes measuring pressure in the range of 0 to 1 MPa relatively straightforward.

Figure 8.27(b) shows the general arrangement of a single-crystal silicon pressure sensor with capacitive pickup. In this case, a capacitive bridge can be formed with two reference capacitors and the output voltage is related to the deflection of the membrane and hence the applied pressure (   ).

     (8.33)

In this case, the accurate positioning of the pickup electrodes is crucial. By controlling the background pressure , it is possible to fabricate the following basic types of pressure sensors:

• An absolute pressure sensor that is referenced to a vacuum ( )

• A gauge-type pressure sensor that is referenced to atmospheric pressure ( )

• A differential or relative type ( is constant).

─── 引自

《 Microsensors, MEMS, and Smart Devices 》

by
Julian W. Gardner
University of Warwick, UK
Vijay K. Varadan
Osama O. Awadelkarim
Pennsylvania State University, USA ───

 

既然是以某種的『機械結構』所構造，即使製作得很小，還是符合『物理力學』之原理。若是缺乏適當的『避震設計』，依舊免不了『振動』與『突波』的影響。所以『數據表』方才特別強調『 High shock survivability 』的乎？下面的實測結果︰

 

【不施加搖晃振動】

pi@raspberrypi ~  sudo python3
Python 3.2.3 (default, Mar  1 2013, 11:53:50) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import time
>>> from sense_hat import SenseHat
>>> 感測 = SenseHat()
>>> while True:
...     壓力 = 感測.get_pressure()
...     print("Pressure: %s Millibars" % 壓力)
...     time.sleep(3)
... 
Pressure: 1012.3779296875 Millibars
Pressure: 1012.384765625 Millibars
Pressure: 1012.3642578125 Millibars
Pressure: 1012.353515625 Millibars
Pressure: 1012.378173828125 Millibars
Pressure: 1012.34765625 Millibars
Pressure: 1012.355224609375 Millibars
Pressure: 1012.345703125 Millibars
Pressure: 1012.364501953125 Millibars
Pressure: 1012.3623046875 Millibars
Pressure: 1012.36083984375 Millibars
Pressure: 1012.396484375 Millibars
Pressure: 1012.35693359375 Millibars
Pressure: 1012.397216796875 Millibars
Pressure: 1012.357177734375 Millibars
Pressure: 1012.398681640625 Millibars
Pressure: 1012.39697265625 Millibars
Pressure: 1012.390380859375 Millibars
Pressure: 1012.403564453125 Millibars
Pressure: 1012.377685546875 Millibars
Pressure: 1012.358154296875 Millibars
^CTraceback (most recent call last):
  File "<stdin>", line 4, in <module>
KeyboardInterrupt
>>> 

 

或可驗證所說矣。如是我們是否更加明白所謂『機電整合』是何事的呢？清楚知道『學科融匯』是進入未來科技世界之『通行證』的嗎？？或將理解『【Sonic π】…… 』一大系列文本所談之事乎！

 

清‧劉鶚‧《老殘遊記》

《詩經》毛詩序

情發於聲，聲成文謂之音，治世之音安以樂，其政和；亂世之音怨以怒，其政乖；亡國之音哀以思，其民困。故正得失，動天地，感鬼神，莫近於詩。先王以是經夫婦，成孝敬，厚人倫，美教化，移風俗。

風聲雨聲讀書聲雖然都是『聲』，但不知有幾人能詮釋『地籟』之『樂』；或許『誦讀聲』偶然入耳，聽之卻有『弦外之音』。終於『寰宇的振動』一分為三，成為了『自然之聲』、『言語之音』以及『動人之樂』！王小玉說書，字字清晰詞詞明白，音似行雲且聲若流水，一時雷鳴九霄之外，忽而泉湧九地之下，彼音擬樂此聲知音，相追相逐鎔鑄成了『天籟』的聲樂旋律！！

───

 

事實上，那些文本

‧ 【Sonic π】聲波之傳播原理︰振動篇

‧ 【Sonic π】聲波之傳播原理︰原理篇《一》

‧ 【Sonic π】聲波之傳播原理︰共振篇《一》

‧ …

的點點滴滴，不只是進入 MEMS 的『先修課』，更為著在分殊專業的今天，所謂『普通科學 』到底該如何講起又怎樣傳播，作點嘗試努力的吧 ！！

今天是『教師節』，省思現下『教』『學』關係的『實況』，不禁令人十分悵惘無奈的啊！！到底一切的教改使『學子』的『壓力』是增是減的呢？？

 

【為何壓力為零？？】

# sense_hat 原始碼
sense_hat/sense_hat.py 


    def get_pressure(self):
        """
        Returns the pressure in Millibars
        """

        self._init_pressure()  # Ensure pressure sensor is initialised

# 壓力為零是初始值！
        pressure = 0
        data = self._pressure.pressureRead()
# 或代表感測器讀取有誤耶？
        if (data[0]):  # Pressure valid
            pressure = data[1]
        return pressure

    @property
    def pressure(self):
        return self.get_pressure()

 

 

 

 

 

 

 

 

 

 

什麼是『微機電系統』 MEMS ？在此引用 State University of New  York 之 Mohammad I. Younis 先生所寫

《 MEMS Linear and Nonlinear Statics and Dynamics 》
by
Mohammad I. Younis

書中之一段說法︰

1.1 What Are MEMS and Why They Are Attractive?

The easiest way to introduce MEMS is to refer to the acronym MEMS itself and what it means. MEMS stands for micro-electro-mechanical-systems. Hence, they are devices in the “micro” scale, in which one or more of their dimensions are in the micrometer range. The “electro” part indicates that they use electric power, for example for actuation and detection, or electronics, for instance for amplifying and filtering signals and for controlling purposes. “Mechanical” means these devices rely on some sort of mechanical motion, action, or mechanism. The word “system” refers to the fact that they function, are designed, and are fabricated as integrated systems and not as individual components. In addition to these features, there are some basic aspects of MEMS that are hidden in the acronym. These can be revealed in this more formal definition of MEMS, which is the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through micro-fabrication technology [1].

This concise definition emphasizes important features of MEMS. The first is the fact that most MEMS are basically sensors and actuators. Examples of MEMS sensors are inertia sensors (accelerometers, gyroscopes), pressure sensors, gas and mass sensors, temperature sensors, force sensors, and humidity sensors. Almost for every physical quantity, there is a MEMS sensor that is developed or being developed to measure it. Examples of actuators are micromirrors to deflect lights in flat-screen TVs, RF switches and microrelays, microgrippers, and generic force and displacement actuators, such as thermal bimorph actuators and comb-drive electrostatic actuators. Thus, historically speaking, the early generation of MEMS researchers
has relied on sensors and actuators journals and conferences to disseminate their research on miniature devices before the introduction of specialized MEMS conferences and journals in the early 1990s. Today, several major MEMS meetings and journals still hold the words sensors, actuators, or transducers in their titles.

The second feature is that silicon represents the core material of this technology. Silicon substrates are commonly used as the platform where MEMS components are built and electrically bonded, although recently other materials, such conductive polymers have been utilized [2, 3]. The fabrication of MEMS devices usually starts with single crystal silicon wafers, which come in many standard sizes (4 in, 8 in, and 12 in). Silicon is the preferred material because of its excellent thermal and mechanical properties (small thermal expansion, high melting point, high toughness, and brittleness with no plastic behavior or hysteresis). In addition, silicon has been used
for microelectronics long before the MEMS technology. Hence, many of the well-established processes to fabricate microelectronics from silicon have been adopted directly or modified slightly for MEMS. MEMS made of silicon can be integrated easily with other electronics components, which are also made of silicon, on the same chip. Besides silicon, a number of materials are used to realize MEMS structures, such as silicon-oxide, silicon-nitride, polysilicon, gallium arsenide (GaAs), aluminum, and gold. These are grown or deposited as thin-films over the silicon substrate, which are then etched or processed by micro-fabrication techniques [4].

Another key aspect of MEMS devices is the fact that they are made through the micro-fabrication technology, which enables fabricating numerous numbers of them at the same time (batch fabrication). Many of the micro-fabrication processes, such as material deposition, evaporation, and etching, can be applied on multiple silicon wafers at the same time. Each wafer can produce hundreds of MEMS devices. This means that each fabrication batch can produce thousands of MEMS devices all at once. Of course, reaching this level of production is not trivial; micro-fabrication processes need extensive research and optimization for each step to reach stable and reliable level of production. However, once this critical stage is passed, the payoff is thousands of devices at very low cost. MEMS devices have replaced many expensive devices for fractions of the cost. For instance, the Analog Devices airbag accelerometers in cars, which today costs less than a dollar, has replaced bulkier more expensive accelerometers, which cost more than US$ 50 apiece.

Another important feature of MEMS is the fact that they are systems. This implies that the components of MEMS have to be designed during the design of the whole system. Assembly of individual MEMS components is expensive, cumbersome, and impractical [5]. Also, when designing a microsystem, its fabrication process must be designed too, otherwise the design many not be feasible or cannot be fabricated. Another implication is that system issues, such as packaging, system partitioning into components, stability, and reliability of the products, must be analyzed and taken into consideration during the design and development cycles.

The fascination in the MEMS technology comes from their distinguished characteristics. MEMS are characterized by low cost, which is a direct consequence of the batch fabrication. They have lightweight and small size, which is desirable for compactness and convenience reasons. In addition, this has opened the gates for new possibilities of implementing MEMS in many places where large devices do not fit, such as engine of cars and inside the human body. Moreover, they consume very low power, which not only does reduce the operational cost but also enables the development of long-life and self-powered devices that can harvest the small amount of energy they need from the environment during their operation [6, 7]. Furthermore, MEMS devices have enabled many superior performances, smart functionalities, and complicated tasks that cannot be achieved in other technologies. Ultra-sensitive mass detectors, high isolation and low-insertion-loss RF switches, lab-on-a-chip bio-sensors, tiny directional microphones for hearing aids (Fig. 1.1), high-temperature pressure sensors for automobile engines (Fig. 1.2), and precise controlled liquid droplets for ink-jet printers are just few examples.

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再輔之以

《 Microsensors, MEMS, and Smart Devices 》

by
Julian W. Gardner
University of Warwick, UK
Vijay K. Varadan
Osama O. Awadelkarim
Pennsylvania State University, USA

書中的『分類圖解』 Classification scheme 和 MEMS 可以量測哪些『物理量』，以及『裝置構造』概要︰

 

8.4 MECHANICAL SENSORS

8.4.1 Overview

Mechanical microsensors are, perhaps, the most important class of microsensor because of both the large variety of different mechanical measurands and their successful application in mass markets, such as the automotive industry. Table 8.4 lists some 50 or so of the numerous possible mechanical measurands and covers not only static and kinematic parameters, such as displacement, velocity, and acceleration, but also physical properties of materials, such as density, hardness, and viscosity.

Figure 8.19 shows a classification scheme for mechanical microsensors together with an example of a device type.

Table 8.4 List of mechanical measurands. Adapted from Gardner (1994)

Figure 8.19 Classification scheme for mechanical microsensors. From Gardner (1994)

The most important classes of mechanical microsensors to date is a subset of only six or so and these constitute the majority of the existing market for micromechanical sensors. Thus, the main measurands of mechanical microsensors are as follows in alphabetical order:

• Acceleration/deceleration
• Displacement
• Flow rate
• Force/torque
• Position/angle
• Pressure/stress

Therefore, we describe in detail here four of the most important types of mechanical microsensors, namely,

• Pressure microsensors (Section 8.4.5)
• Microaccelerometers (Section 8.4.6)
• Microgyroscopes (Section 8.4.7)
• Flow microsensors (Section 8.4.8)

 

在這杜鵑呼嘯即將過境，或仍可借著今日『中秋佳月』之明，略窺 MEMS 之面貌的耶！！

 

 

 

 

 

 

 

 

 

在探討『微機電系統』 MEMS 原理前，先思考

MEMS are made up of components between 1 to 100 micrometres in size (i.e. 0.001 to 0.1 mm), and MEMS devices generally range in size from 20 micrometres to a millimetre (i.e. 0.02 to 1.0 mm). They usually consist of a central unit that processes data (the microprocessor) and several components that interact with the surroundings such as microsensors.^[1] At these size scales, the standard constructs of classical physics are not always useful. Because of the large surface area to volume ratio of MEMS, surface effects such as electrostatics and wetting dominate over volume effects such as inertia or thermal mass.^{[citation needed]}

Microelectromechanical systems chip, sometimes called “

lab on a chip “

 

所說何事。為何『經典物理』通常不合適的呢？或許『尺寸』很小時，必須要考慮『量子效應』。更重要的是主導的『作用力』以及各類『非線性』的來源與一般物理學講的『剛體』、『流體』、『連續體』…等等的巨觀『線性模型』 情況不同，通常需創造適當的『系統模型』。而且『單‧多‧巨』個體涉及的『計算複雜度』和『系統穩定性』實際上大異其趣。此時如果回顧一下

《 W!o 的派生‧十日談之《四》》

當龐加萊 Poincaré 與玻爾茲曼 Boltzmann 等人創用『相空間』phase space 來描述物理上『三體問題』的時候，催生了︰

現今的混沌理論 Chaos theory 描述『非線性』系統在一定參數條件下會發生『分岔』 bifurcation 現象，周期運動與非周期運動可能相互『糾纏』，以至於通往某種非周期又可以有序之運動理論。因此它是一種兼具『定性』與『定量』的分析之思考方法，用以探討動力系統中無法僅用『一時單一』的數據，必須用『連續整體』的數據才能加以解釋或是描述該系統之行為。

如果問大自然『作計算』嗎？假使答『作』，那該如何『作計算』的呢？？比方說，人類要怎麽『模擬』一莫爾 個氣體分子之『運動』的呢！事實上，想深入了解『三體互動』恐怕都需要借助『計算機』的哩！！那麼『自然律』果真能與『理化計算』等同的嗎？？？

所以就算今天已經有了『量子電腦』，那所需之『時間』 time 與『空間』 space ，在『計算』上所用之『資料』和『結構』，依然十分重要！也許有人認為，難到不能夠依賴『統計學』的嗎？只是適用於『晴天』的『統計』，誰曉得能不能用於『雨天』的呢！！

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與

《失之豪釐，差以千里！！《中》》

假使說一個系統 很『靈敏』 sensitive ，是講當系統的『輸入』 有一點『變化』 ，系統之『輸出』 ，產生很大的『改變』 ，也就是說

的『比值』很大。

然而『靈敏度』 Sensitivity 一詞，用於不同的領域、場合，常帶著點不同的意味，遇到此詞時，避免望文生義。如果將『靈敏度』用於『量測儀器』，通常是指儀表對於『輸入變化』的『分辨能力』 ，一般用著某種 之『比值』來表示。

表示要是透鏡和兩個物件之間的夾角少於 ，透鏡的觀察者便無法分辨出有兩個物件。不要以為『分辨能力』愈『大』，就一定是愈『好』，通常顯微鏡的放大倍數『越高』，可能操作上也『越難』 。設使每個人的『視力』都能睹『秋毫之末』，怕世間『美』『醜』的『標準』會變的吧？難想像會發明『幾 K 』的電視的哩！

『量測裝置』 是一個『物理系統』，待量測『自然萬象』 也是一個『物理系統』，彼此『交互作用』 ── 能量和物質轉化與交換 ──，得到『度量』之數據，『測知』現象系統的『狀態』。自考察『現象』之『狀態』上來講，假使從『微觀上』將之當成由『粒子系統』所構成，或許可以用『相空間』之『相圖』來觀察︰

要是『相空間』之『相圖』發生了『相交』？也許是碰到『混沌』的吧！還是遭遇了『相變』。

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或許可為概念的先導乎？也許像感受下述現象所引發的驚訝一樣！

 

pi@raspberrypi ~ $ sudo python3
Python 3.2.3 (default, Mar  1 2013, 11:53:50) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.

>>> from sense_hat import SenseHat

>>> 感測器 = SenseHat()
>>> 溫度 = 感測器.get_temperature()
>>> 壓力 = 感測器.get_pressure()
>>> 濕度 = 感測器.get_humidity()

>>> print(溫度)
30.864919662475586

# 為什麼大氣壓力為零！！
>>> print(壓力)
0

>>> print(濕度)
51.61996078491211

>>> 壓力 = 感測器.get_pressure()
>>> print(壓力)
1014.302978515625

# 當真變化如是的快耶？？
>>> 溫度 = 感測器.get_temperature()
>>> print(溫度)
30.955646514892578

>>> 濕度 = 感測器.get_humidity()
>>> print(濕度)
51.439903259277344

>>>