A positioning goniometer or goniometric stage is a device that rotates an object precisely about a fixed axis in space. It is similar to a linear stage— however, rather than move linearly relative to its base, the stage platform rotates partially about a fixed axis above the mounting surface of the platform. Download this app from Microsoft Store for Windows 10 Mobile, Windows Phone 8.1. See screenshots, read the latest customer reviews, and compare ratings for Phone sensors.
A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, gōnia, meaning angle, and metron, meaning measure.
The first known description of a goniometer, based on the astrolabe, was by Gemma Frisius in 1538.
Applications[edit]
Surveying[edit]
Prior to the invention of the theodolite, the goniometer was used in surveying. The application of triangulation to geodesy was described in the second (1533) edition of Cosmograficus liber by Petri Appiani as a 16-page appendix by Frisius entitled Libellus de locorum describendorum ratione.[1]
Communications[edit]
The Bellini–Tosi direction finder was a type of radio direction finder that was widely used from World War I to World War II. It used the signals from two crossed antennas, or four individual antennas simulating two crossed ones, to re-create the radio signal in a small area between two loops of wire. The operator could then measure the angle to the target radio source by performing direction finding within this small area. The advantage to the Bellini–Tosi system is that the antennas do not move, allowing them to be built at any required size.
The basic technique remains in use, although the equipment has changed dramatically. Goniometers are widely used for military and civil purposes,[2] e.g. interception of satellite and naval communications on the French warship Dupuy de Lôme uses multiple goniometers.
Crystallography[edit]
In crystallography, goniometers are used for measuring angles between crystal faces. They are also used in X-ray diffraction to rotate the samples. The groundbreaking investigations of physicist Max von Laue and colleagues into the atomic structure of crystals in 1912 involved a goniometer.
Light measurement[edit]
Goniophotometers measure the spatial distribution of light visible to the human eye (often luminous intensity) at specific angular positions, usually covering all spherical angles.
In medicine[edit]
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A goniometer is used to document initial and subsequent range of motion, at the visits for occupational injuries, and by disability evaluators to determine a permanent disability. This is to evaluate progress, and also for medico-legal purposes. It is a tool to evaluate Waddell's signs (findings that may indicate symptom magnification.)
Rehabilitative therapy[edit]
In physical therapy, occupational therapy, and athletic training, a goniometer measures range of motion of limbs and joints of the body. These measurements help accurately track progress in a rehabilitation program. When a patient has decreased range of motion, a therapist assesses the joint before performing an intervention, and continues to use the tool to monitor progress. The therapist can take these range of motion measurements at any joint. They typically require knowledge about the anatomy of the body, particularly bony landmarks. For example, when measuring the knee joint, the therapist places the axis (point of rotation) on the lateral epicondyle of the femur, and lines up the stationary arm with the greater trochanter of the femur. Finally, the therapist lines up the moveable arm of the goniometer with the lateral malleolus of the fibula, and records a measurement using the degree scale on the circular portion of the tool. Reading accuracy is sometimes a problem with goniometers. Issues with the intra-measure (between measures) and inter-tester (between clinicians) reliability may increase as the experience of the examiner decreases. Some studies suggest that these errors can be anywhere between 5 and 10 degrees.[citation needed]
These goniometers come in different forms that some argue increase reliability.[3][4] The universal standard goniometer is a plastic or metal tool with 1 degree increments. The arms usually are not longer than 12-inches so it can be hard to accurately pinpoint the exact landmark for measurement. The telescopic-armed goniometer is more reliable—with a plastic circular axis like a classic goniometer, but with arms that extend to as long as two feet in either direction.
More recently in the twenty-first century, smartphone application developers have created mobile applications that provide the functions of a goniometer. These applications (such as Knee Goniometer and Goniometer Pro) use the accelerometers in phones to calculate joint angles. Recent research supports these applications and their devices as reliable and valid tools with as much accuracy as a universal goniometer.[5][6][7]
Modern rehabilitative therapy motion capture systems perform goniometry at the very least measuring active range of motion.[8] While in some cases accuracy may be inferior to a goniometer, measuring angles with a motion capture system is superior at measuring during dynamic, as opposed to static situations. Furthermore, using a traditional goniometer takes valuable time. In the clinical context, performing manual measurements takes valuable time and may not be practical.
Surface science[edit]
Contact angle goniometer[edit]
In surface science, an instrument called a contact angle goniometer or tensiometer measures the static contact angle, advancing and receding contact angles, and sometimes surface tension. The first contact angle goniometer was designed by Dr. William Zisman of the United States Naval Research Laboratory in Washington, D.C. and manufactured by ramé-hart (now ramé-hart instrument company), New Jersey, USA. The original manual contact angle goniometer used an eyepiece with microscope. Today's contact angle goniometer uses a camera and software to capture and analyze the drop shape, and is better suited for dynamic and advanced studies.
Surface tension[edit]
Contact angle goniometers (q.v.)can also determine the surface tension for any liquid in gas or the interfacial tension between any two liquids. If the difference in densities between the two fluids is known, the surface tension or interfacial tension can be calculated by the pendant drop method. An advanced instrument often called a goniometer / tensiometer includes software tools that measure surface tension and interfacial tension using the pendant drop, inverted pendant drop, and sessile drop methods, in addition to contact angle. A centrifugal adhesion balance relates the contact angles to the adhesion of the drop to the surface. A gonioreflectometer measures the reflectivity of a surface at a number of angles.
Positioning[edit]
A positioning goniometer or goniometric stage is a device that rotates an object precisely about a fixed axis in space. It is similar to a linear stage— however, rather than move linearly relative to its base, the stage platform rotates partially about a fixed axis above the mounting surface of the platform. Positioning goniometers typically use a worm drive with a partial worm wheel fixed to the underside of the stage platform meshing with a worm in the base. The worm gear may be rotated manually, or by a motor in automated positioning systems.
Knife and blade cutting edge angle measurement[edit]
The included cutting angles of all kinds of sharp edge blades are measured using a laser reflecting goniometer. Developed by the Cutlery and Allied Trades Research Association (CATRA) in the UK, a range of devices can accurately determine the cutting edge profile including a rounding of the tip to ½°. The included angle of a blade is important in controlling its cutting ability and edge strength—i.e., a low angle makes a thin edge optimized for cutting, while a large angle makes a thick edge that is less sharp but very strong.
Doctor blade inspection[edit]
Used doctor blades, from gravure and other printing and coating processes, can be inspected with a goniometer, typically with a built-in light source, to examine the blade edge for wear and correct angles. A difference in angle from that set on the machine may indicate excessive pressure, and a range of angles ('rounding') probably indicates a lack of stiffness, or wear, in the blade holder assembly.
See also[edit]
| Wikisource has the text of the 1911 Encyclopædia Britannica article Goniometer. |
- Protractor – Angle measuring instrument
- Trigonometry – In geometry, study of the relationship between angles and lengths
References[edit]
- ^Brezinski, Claude; Tournès, Dominique (2014). André-Louis Cholesky: Mathematician, Topographer, and Army Officer. Basel: Birkhäuser. ISBN978-3-319-08134-2.
- ^Boucher, Jacqueline (2007-05-03). 'Radio receiver workload accelerates'. Retrieved 2007-09-21.
- ^Milanese, Gordon. 'Reliability and concurrent validity of knee angle measurement: Smart phone app versus universal goniometer used by experienced and novice clinicians'. Manual Therapy. 5: 1–6.
- ^Jones, Sealey (2014). 'Concurrent validity and reliability of the simple goniometer iPhone app compared with the universal goniometer'(PDF). Physiotherapy Theory and Practice. 30 (7): 512–516. doi:10.3109/09593985.2014.900835. hdl:2328/37026. PMID24666408. S2CID28719817.
- ^Ockendon, Matthew (2012). 'Validation of a novel smartphone accelerometer-based knee goniometer'. The Journal of Knee Surgery. 25 (4): 341–345. doi:10.1055/s-0031-1299669. PMID23150162.
- ^Jones, A (2014). 'Concurrent validity and reliability of the simple goniometer iphone app compared with the universal goniometer'(PDF). Physiotherapy Theory and Practice. 30 (7): 512–516. doi:10.3109/09593985.2014.900835. hdl:2328/37026. PMID24666408. S2CID28719817.
- ^Kuegler, P.; Wurzer, P.; Tuca, A.; et al. (2015). 'Goniometer-apps in hand surgery and their applicability in daily clinical practice'. Safety in Health. 1: 11. doi:10.1186/s40886-015-0003-4.
- ^'Markerless Motion Capture. Biomechanical Analysis'. EuMotus.com. Retrieved 2018-01-15.
External links[edit]
Today’s every smartphone is coming with a set of sensors. There are several lists of sensors are equipped with smartphones for getting things done. So what are these smartphone Sensors useful for? This guide will help you to know about every sensor present on your mobile.
Smartphone Sensors Wiki
1. Gyroscope
The gyroscope is an orientation sensor with accurate precision. It simply calculates the angular velocity of the device. The gyroscope in smartphones is used for tracking the rotation of the device. When you play games like N.O.V.A, Modern Combat: Sandstrom you can feel rotation, and the axis. The gyroscope calculates data along with accelerometer and sends the data to the game.
Popular apps like Google Sky Map, Android Photo Sphere camera, and much more apps use the Gyroscope data for accurate results.
2. Accelerometer
Accelerometer measures and calculates the device acceleration. It calculates the three axis orientation of the device and sends the data to the required apps and games.
For example, in Android, you can use portrait or landscape mode. When you move the smartphone in portrait and landscape modes the phone screen, automatically adjust according to the position with the help of accelerometer. It is one of the most widely used android phone sensors.
3. Proximity Sensor (what is proximity sensor in mobile?)
When you are on the call and place the phone near to the ear the light turns off, ever wondered how it works? A Proximity Sensor in mobile will detect the near object and send the data to your phone. The sensor works by activating a small beam of light which is reflected by our skin and the device turns off the screen display temporarily.
4. Light-Sensor (Ambient light sensor in mobile)
Light Sensor is used in Smartphones for automatic display light adjustment. This sensor calculates the Illuminance of the environment and sends the data to the device. Then the device calculates the required display brightness and applies the effect.
5. Barometer (What is barometer sensor in mobile?)
A barometer is a sensor which we usually find in high-end smartphones. As we know from the school Physics Barometer measures the atmospheric pressure. However, there is no direct use of smartphones; the Barometer in mobile works with GPS sensor about the device sea level measurements for greater GPS accuracy.
6. Heart Rate Monitor
As its name implies this sensor measures the heart rate of the user. It measures the heart rate by placing the user’s finger on the sensor. It calculates the user pulse by minute wise and displays on the screen.
7. Fingerprint Sensor
Fingerprint sensor doesn’t need any introduction. This sensor became most common these days, and it is coming equipped even with a low-end smartphone.
8. Pedometer
Pedometer sensor calculates the number of steps taken by the user. But many smartphones using accelerometer data for the Pedometer data, this data is not accurate as the real Pedometer sensor does. Only a few smartphones are equipped with real Pedometer sensor; Google Nexus 5 is one of them.
9. GPS
Global Positioning System also considers as a sensor. A GPS module will connect to the satellite and gives you an accurate position result.
10. Touch Screen
The touchscreen of a smartphone is also a kind of sensor which responds to human contact. A touchscreen is made of multiple layers of glass and works with the pressure of your finger.
11. Hall Sensor
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If you have used the old devices which used to have flip covers which were functional, like had an option to switch off the screen when you flip them on, then those used to have this kind of Hall Sensor which can sense the magnets, and respond. Even the latest gen phones from Samsung, and Apple comes with Hall Sensors.
12. Digital Compass
This is the rarest sensor we can find on a mobile phone, the main reason of ignoring this one is the combination of other sensors with which the mobile can get its orientation and the magnetic readings of where it is pointing to. This sensor gives the direct position and direction of the device to the apps without any issue. It also doesn’t require calibration which most of the new devices need.
13. Augmented & Virtual Reality
This is a combination of different hardware which includes a couple of different cameras, and a couple of different Lasers which will detect the different depth of the things. These will later help to organize different things via the AR or VR.
14. Infrared Sensor
This sensor is used in the devices to project the infrared dots and then they are scanned with an Infrared Scanner. This scanner is mostly used to encrypt the device with the face data of any person.
15. Pressure Sensor
This particular sensor is found in a limited number of devices, this is used to actually detect the amount of pressure being put on the device on the sides or on the screen which will act as additional inputs to the software for preset functionality.
16. Temperature Sensor
This particular sensor is rarely found on the devices, this is used in order to detect the internal and external temperature of either the device or the surrounding temperature.
17. Iris Scanner
This scanner uses infrared and a couple of cameras to actually scan the pattern found in the iris of the peoples, this is again in a term used to encrypt the device with the eyes of a particular person.
18. Infrared Remote
This device is used to give the singles to different machines which use infrared remote to receive signals and perform a particular function.
19. Air Humidity Sensor
This particular sensor is used to find the humidity level in the air. The sensor is found only around one or two devices.
20. Pulse Oximeter
Pulse Oximeter sensor is used to find the amount of oxygen that is found in your blood. This sensor will not take any blood sample but will identify the oxygen level by the light.
21. Geiger Counter
Geiger Counter is made to detect and measure the number of ionizing radiations in different places. It is found in the really low amount of devices but can be really useful if you live in places near nuclear reactors.
22. NFC
Near Field Communication sensor is used to validate transfer between two devices. This can easily be used to make financial transactions, and can even be used to share photos aand videos.
23. Laser
The laser is used in different devices to actually measure the distance between your mobile phone and the thing behind it. It can even be used to focus your camera more accurately.
24. Air Gesture
Air Gesture has been used in devices such as Samsung Galaxy S4 & Samsung Galaxy S5 where you can easily put your fingers above the display to actually make some features work.