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General information

iComparator is an application dedicated the everyday use. Consider it as a swiss-army knife. It is not for construction nor exact measurement, use it to get an idea:

  • what is the height of that tower when you visit a city
  • how far away is the mountain over there
  • what angle is this road
  • the sound I hear, what is its frequency

This is where iComparator will help you, just handy and always carried with you.

Settings screen

This is the second tabbar item. Here you select and start the desired tool.
The picker let you choose the tool and the OK sign returns you to the first page and starts the application. On top you find a setting for the auto track timer, see more there.

Light

There are two light modes, front and back. Both are almost the same, except for the input. You can choose to use the front or back camera. The camera is used to measure the light strength of the pointed scene. You can use this to have an idea of the light source or how the illuminated a room is. The displayed value is measured in exposure value (EV) as used in photography and referenced to ISO100. You could use this direct to manually set your camera (better is to use the iZoner app). A increase of 1 unit to the EV means double the intensity of the light source, this is also how our eyes (and cameras) work. By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

Noise/soundpressure

Occasionally you might want to know how noisy it is and want to decrease it. You test with some isolating materials and/or turn equipment off. But is it really more quiet or just an imagination? With this mode you can compare the current sound/noise to a second situation. Just press the lock icon and the comparison begins. Close to computers or in an office a number around 60 to 70 is normal. This figure is not absolute, it depends on the microphone, amplifiers etc. and can only be used as reference. The maximum an iPhone can measure is 120. Note that an increase of 10 (dB) is a doubling of sound pressure. By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

Pitch

This mode is an extension on the previous one, the sound is sampled and stored in memory. After a predefined interval the samples are evaluated with an FFT algoritm. From this calculation, the dominant (strongest) frequency is the result. When you supply a pure tone from e.g. a guitar or piano the frequency of that note is displayed. When you set a signal with more distortion and/or harmonics, the most abundant note is given. The sensitivity slider is used to give a level, above which the measurement begins.
By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

One important note : after starting this mode it might be possible that it looks if the app does not respond any more when you tap the settings tab. Please be patient, the app is still running and calculating.

Angle

The angle mode can be used to find the angle of a roof or to check if a washing machine is horizontal. We choose to select the 2 most comfortable directions, you can place your iPhone on its back on a surface. Lifting either the left or right side, will create a rotation along the Y-axis. Lifting the top or bottom up is a X-axis rotation. Both figures are given in the columns under the symbolic icons. Sometimes is is more convenient to have the display in another mode, roads are not given in degrees but in percentage. Press the % sign and the display changes. Please be aware of two different approaches to this mode, the most used one is used by this app. For every x meter movement in the horizontal direction the vertical displacement is measured. These are divided and multiplied by 100. The horizontal movement is a projection, not the actual travelled path. So 100 meter movement and 100 meter ascend gives an angle of 45 degrees or 100%. The actual travelled path (according Pythagoras) is sqrt (100 * 100 + 100 * 100) = 141 meters. The are systems (not used here!!!) that say 100 meter travelled path and 100 meter ascend is 100%, now this is 90 degrees.

l = travelled path
Δh = ascend
d = horizontal movement
α = angle

By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

Vibration

When an object is vibrating so much that your touching iPhone (take care not to damage it) can detect acceleration, it can be used to do a FFT calculation on the data. The result will be the dominant vibration frequency. Use this mode with great care. Never stick your iPhone direct without any soft isolation to the vibrating object. By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

Acceleration

Your iPhone is capable of detecting accelerations, both positive and negative. In fact it is a sudden change in the gravity field. The acceleration is captured in all 3 axis, holding your iPhone horizontally and looking at the screen :

  • x axis : left - right (in a car, the corners)
  • y axis : front - back (in a car, acceleration and breaking)
  • z axis : up -down (in a car, bumps)

The car example is just for explanatory purposes, don not use it in real life.
Every time the clear button is pressed, the actual orientation of the device is measured (is also an acceleration) and is used as an offset to normalize the measurement. By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

Magnetic

The magnetic field can be measured in 3 directions (in fact is the x-axis a magnetic compass). Besides measuring the earth magnetic field, other objects can be investigated. These object might be laptops, electronic equipment etc. Why could you be interested in these fields? Sometimes you should avoid placing sensitive objects in strong magnetic environments, like coils and cards with magnetic data. By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

Heading

The heading mode is a digital version of a compass, with an advantage. A normal magnetic compass points, as the name implements, to the magnetic north pole. The problem is that this reference point is not a fixed point, it travels around ( around 60 km per year at this moment). A more stable reference point is the earth's axis. For navigation over longer distances it is very important to take in account this differences in values. The heading mode of iComparator shows both values, the magnetic and true north pole. By pressing the lock button (mid down under), you capture the current value. From now on every change is displayed. Until you press the clear button (right down under), all value are compared to the locked one.

GPS

First of all, iComparator is not a navigation device nor it contains any maps. What is the GPS mode? It is just a display for some GPS data. You can see your real speed, location and altitude. The course displayed here differs from the heading mode (see above). The course is calculated from location to location at a short interval, but the must be a displacement. In stationary circumstances GPS can not be used. The last line shows the accuracy in the horizontal and vertical plane. Take care of these figures when you use the other values. So if the altitude is 100 meter and the vertical accuracy is 20 meter, the actual altitude can be between 80 and 100 meter. There is no lock button, as you can lock the satellites :-).

Track

The track mode is an extension on the GPS. When it starts the location is saved. At a new location the travelled path is calculated and displayed (in real time at the segment value). Every time you press on the tape icon, the current segment is added to the total and reset to zero. So if you travel with lots of corners (like jogging in the street), at every corner you add the segment and get the real length. This might not always be convenient, so you can make the app do it automatically every period. Under the settings tab the interval can be set and then switch on with auto get. Take this period not to long to avoid missing corners ( use 60 seconds and run in a circle, your result will be disappointing). Also take this period not too short, travelling just 3 meters with a accuracy of 10 meters will result is a very in-accurate reading. The setting depends on your usage. Pressing the clear button will reset the accumulated total and current segment.

Torch

A simple mode for an emergency light. The camera "flash" is used to illuminate a small area. Do not use this for an extended period, the battery drains fast and your iPhone will heat up quickly.

DTMF

DTMF stands for "Dual Tone Multi-Frequency". It is used to transfer a keypress by a mix of two tones. This is e.g. used by telephones to send a number. Sometimes it is also used by remote controls. For this latter purpose iComparator has it available. When you are not able to send the required tones to your equipment (alarm system) or to a computer guided menu from your holiday location, you can use this mode.

Height

This is one of the most sophisticated modes of this application. First check if you have a GPS fix, shown by a green arrow in the upper right corner. Point the camera to an object that you want to measure (a tree, building or bridge). If the view is not the right size you could press the other view by pressing the magnify glass. To help you pointing, there is a small white or black circle (selectable). This object must be above the iPhone (angle is > 0), now press the mountain icon. Move in a straight line to the object (initial location, new location and object must be on a straight line). Now point the camera again to the object (same part) and read the height and current distance to the object. This height is an approximation and depends on the separation of the two locations, pointing accuracy and GPS accuracy. If the calculated height or distance is less than the GPS accuracy, as triangle will blink in the upper bar. If you want to start with a new measurement, press the clear button and the mountain button re-appears.

Distance

Sometimes you want a good guess of the distance to an object, you want to know how far it is to a mountain or building.
This is where the distance mode of iComparator comes in. It is not very useful for nearby objects or the size of your room (except when you live in a castle). First check if you have a GPS fix, shown by a green arrow in the upper right corner. Point the arrow to an object that you want to measure (a tree, building or bridge). Now press the globe icon. Next move to another place, don't move towards the object (the three points may NOT be on a straight line). Point the arrow to the same object. If the measurement is valid a distance from the current location is displayed. If the calculated distance is less than the GPS accuracy, as triangle will blink in the upper bar. If you want to start with a new measurement, press the clear button and the globe button re-appears.


 

 

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Laatst bijgewerkt: 25 juli 2012