Questions tagged [sensor]

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15 views

Does a tuning fork's resonance frequency increase with a repulsive force on it in AFM?

I have a tuning fork sensor with a probe tip that would be used in atomic force microscopy. Am I correct that the quartz tuning fork's resonance frequency increases with a repulsive force on it and ...
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23 views

Subtracting gravity from accelerometer readings using rotation vector [closed]

I have measurements from a Android smartphone accelerometer sensor. The sensor readings are in three dimensions x, y and z and contain also gravity. The unit of measure is m/s^2. In addition to the ...
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26 views

Clarifications on the calibration of a magnetometer?

I've been reading up on magnetometer calibration (sensor fusion in general) recently and got confused about some things. To my understanding, hard iron effects (e.g. inductors and magnets) which are ...
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20 views

How is the synthetic aperture of a radar done?

In the case of SAR (synthetic aperture radar), the Doppler effect is used to simulate an antenna (syntetic) whose resolution is better. What I would like to know is how this is done in detail, what ...
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1answer
23 views

How is measurement uncertainty defined / calculated (of a sensor or measurement)?

Textbooks and online sources often say the industry standard for uncertainty is given at a confidence interval of 95 %. This means out of 100 measurements, 95 would achieve the specified value and ...
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2answers
43 views

Is there any way to differentiate UV light from visible or IR light?

I'm working on a small sensor system that responds to only UV light and I wanted to know that is there any way to differentiate between UV light and the rest of the spectrum like using lens if so then ...
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20 views

Calculating dew point, which air temperature should I use (inside vent or outside)?

I'm trying to make my air quality sensor resistant to dew. This air quality sensor has vent with fan, which doesn't "like" to have dew inside. My idea is to use heater and connect it to this ...
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12 views

Optimum Sensor placement

I have 8 thermocouples on a rectangular object (battery) heat is being produced within the battery and at the tabs where the current is flowing out. I’m planning on using a voronoi diagram to estimate ...
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22 views

Brightness Temperature layered atmosphere

I'm trying to figure out how to apply the radiative transfer model to calculate the brightness temperature Tb in microwave (Rayleigh–Jeans approximation) considering atmosphere and no scattering. If I ...
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1answer
65 views

How exactly does a (capacitive) humidity sensor work?

How exactly does a humidity sensor work? For example, how can it differentiate between a relative humidity of 30 % and 35 %? I know how a capacitance works but for me that principle is way too high ...
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1answer
19 views

What is a piezoelectric sorption detector?

I'd like to know what a piezoelectric sorption detector is. I can hardly find information about, only a small number of research papers which are mostly not accessable for me. Only given from the term ...
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2answers
23 views

Measuring real time water usage with live water pressure monitoring

My home started seeing high water bills recently. My water company doesn't provide live water meter readings. There is a water meter on the street which I can monitor while water is being used but I ...
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1answer
38 views

How does a weather station temperature sensor work? (physics behind)

In an automatic weather station, a temperature-measuring electronic sensor (which is typically 1,5 m in the air above a grassy ground and covered from direct sunlight) is in a certain way coupled to ...
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40 views

Any method to detect extremely weak electromagnetic wave signal? (10^12Hz, level ~10^(-28) Watt per meter^2 per Hz)

Could you please let me know whether there is any method on the Earth to detect some EXTREMELY weak electromagnetic wave signal, if it is a planar wave, if its exact waveform is completely known (...
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1answer
32 views

Measure fluid speed by using a hot plate [closed]

I would like to figure out whether it is possible to measure the speed of a fluid by letting it flow across a hot plate. I was thinking about using the formulas for forced convection. The plate is ...
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0answers
48 views

Accelerometer vs linear acceleration during an impact

I am trying to understand the relation between the accelerometer and linear acceleration during impacts. At work we have an accelerometer and gps onboard sensors installed in a few cars. The ...
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0answers
228 views

Graph analysis of accelerometer data

I used my mobile accelerometer sensor to collect data from a moving bike where I held it in my hand in a way that the smartphone sensor +Y axis is in the direction of the moving bike always. This can ...
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0answers
44 views

What does it mean by (±20%) in sensitivity of a pressure sensor?

Sensitivity: (±20%) 15.5 pC/psi (225 pC/bar) this the sensitivity rating of a pressure sensor. what does it mean by (±20%).
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26 views

How to measure distance between object and mobile phone using camera? [duplicate]

I am trying to determine the distance between object being photographed and the mobile camera which is capturing the photo. The only device that is used is mobile phone, can we get depth or distance ...
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1answer
40 views

Total output power of a laser

What is the interpretation of and the difference between the total power and total output power of a pulsed laser? How are these parameters measured and which type of detectors are the most ...
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1answer
91 views

Slots in optical incremental encoder

How can I calculate the amount of slots I need in my optical incremental encoder 's code wheel? For example, how many slots there should be, if I want to determine the position of screw which is ...
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1answer
60 views

How LHC sensors work? [closed]

newbie here. I am here because after working with Raspberry Pi sensors and Analog to Digital converters, and computer processors, I wondered how exactly do sensors in large scale physics experiments ...
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2answers
81 views

Would a speed camera register more speed if it moves in the opposite direction than the object it's measuring?

Earlier today, I was talking with my friend about speed cameras measuring different speeds when moving. This is the situation: I am the red car and I'm driving ...
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1answer
66 views

Basics of camera calibration

I tried to find some useful explanation about camera calibration and stereo camera setup in the web but was completely overwhelmed by the hairiness of the content: but seriously though, does it have ...
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1answer
36 views

Why photodiode measures random phase superpositions on continuous-wave (10kHz) white light?

I measured a 10 kHz modulated white light using a photodiode (Thorlabs PDA10A): Unexpectedly, the photodiode output sensitively depends on the orientation and position of the photodiode. For two ...
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1answer
40 views

Unique optical map of a uniform metal object

Given a metal object (let us say a perfect planner uniform surface) that has been exposed to external environment factors such as sun, wind, rain and others for couple of years. This object has been ...
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2answers
217 views

Measuring pressure or weight from an uneven weight distributed surface

I am new here so I hope I'm posting it at the correct place. I am having some troubles with some of my force sensors. My case is like this: I have a body which have a weight. However, the surface is ...
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1answer
67 views

Can a syringe be used as a hanging scale if needed?

FYI: This is not a homework q; I am just curious... You can assume that... the syringe tip cap creates a "perfect" seal, i.e., keeps air from flowing in/out! the syringe is completely depressed ...
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1answer
87 views

Estimate pendulum motion

I have a simple system: a pendulum and two sensors (RADAR which will tell the distance $dx$ and $v_x$ and a Gyroscope, the gyroscope is giving me the information about $\omega$ - angular velocity) as ...
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0answers
25 views

How to Measure Electric-Field Probe Sensitivity?

I am doing some reading on current methods for detecting electric fields. A figure of merit for the systems is, naturally, the minimum strength of field that can be measured, in units of Volts per ...
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0answers
39 views

Why does a cooking thermometer show different temperatures when touching the container of a liquid?

I have a cooking thermometer that looks like a 10-15 cm long metal rod, that can be inserted into the thing you want to measure the temperature of: When inserted into boiling water, I observed that ...
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1answer
29 views

What are the magnitude of voltage fluctuations in field surrounding the human head?

How much would the scale of the electric field caused by neuron activity in the brain vary as it radiated from the scalp? Also what would be the typical noise level over the same space attributable to ...
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1answer
94 views

When the barometer drops, my well level seems to rise - how?

I have a deep water well, with a length of 1/4" drip tubing, open at the bottom, taped to the pump 180' down. The other end of the tubing is connected to a gauge pressure sensor in the cabinet of my ...
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1answer
90 views

Phone accelerometer - formula to calculate angular gravity

I am taking readings from the accelerometer of a smartphone and want to account for gravity. My device reports residual gravity as "10g" (device stationary, screen facing up). As the angle of the ...
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0answers
97 views

Need an equation to calculate the list of latitudes and longitudes of an off-nadir sensor with a given half angle

I need a deterministic way to determine a list of latitude and longitudes of an off-nadir pointing sensor for a given half angle. Below is a depiction of the problem. It isn't too hard to calculate ...
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1answer
52 views

Piezoelectric powder solution to measure extremely high pressure

Idea - While reading about piezoelectric materials, I thought about mixing piezoelectric powder with silicon oil to measure extremely high pressures (of up to 4000bar). Experiment - Consider a ...
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3answers
180 views

Why do sensors that emit higher frequency signals give more accurate data?

I am doing a technical presentation about RADAR and LiDAR. I understand that LiDAR is several times more accurate and capable of producing really detailed 3-D maps of their surroundings, while RADARs ...
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2answers
2k views

Calculating Velocity from Acceleration (Accelerometer)

I am using the Accelerometer in an Android Device to track and detect certain motions, using only one axis as the motions are linear along that axis. I am using a simple filter to remove the noise ...
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2answers
7k views

What plastic-like materials allow IR to pass through them? [closed]

What plastic-like materials allow IR to pass through them? Material should be solid and plastic like. Does't care if it is transparent to light or not. IR ray is emitted by Sharp distance center so it ...
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2answers
69 views

Physical processes taking place inside Germanium detectors

Reading about differences between Silicon detectors and Germanium detectors, I decided to learn a bit more about the latter, since I've always used Silicon detectors in all the experiments I worked ...
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1answer
58 views

Keeping sensors at constant temperature

I need to measure the performance of some sensors with a strong temperature dependency. Later on, I will do some calibration for the entire temperature range, but for the moment I just want to do a ...
3
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1answer
301 views

How does the “Electromagnetic Position Tracking” work, exactly?

I've been searching the web for the technology of the "Electromagnetic Position Tracking1," and have found the web to be surprisingly ineffectual! I've just came up with some preliminary and basic ...
3
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2answers
626 views

Inductive sensor - How does it work?

I can't understand how the system sketched here physically works: 4 = permanent magnet, with residual magnetization $B_r$ 6 = ferromagnetic core with a coil around it 7 = ferromagnetic toothed ...
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1answer
829 views

Why can't I use a gyroscope/accelerometer only as a compass?

I am seeing this from the usual smartphone sensors. These sensors (Android here e.g.) take the magnetic field data as input. That is okay, but some phones do not have a magnetic field sensor (they ...
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1answer
245 views

Is surveilluminescence an April fool's joke or is the science legitimate?

This website and in particular this paper, describe how one can 'see' the 'sightfield' of a camera. To quote, [A] linear array of computer-controlled LED lights is held in front of a surveillance ...
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1answer
295 views

How can I calculate the sensitivity of a seismometer?

I would like to know how to find the minimum ground motion a seismometer can measure, specifically if a certain seismometer can measure 1 micron/sec velocity. I have a few specs from the datasheet but ...
1
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1answer
314 views

Is it possible to “override” the Earth magnetic field locally? [closed]

For a mobile application I am developing I would like to know which direction the phone is facing. In the outdoor we can of course use the magneto meter in combination with a gyroscope. However, ...
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0answers
57 views

Is it possible to make an imaging array differential?

As described in this comment on a Slashdot post, exposing an imaging sensor to light accumulates charge in a well (i.e. pixel) on a piece of silicon. The well can only hold so much charge (release so ...
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1answer
295 views

Filter for RGB separation

Looking at Bayer filter of a typical consumer camera, one can easily see that sensitivity of the filter for each color is all over the place. Are there filters similar to Bayer that do a better job at ...
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0answers
326 views

Can I calculate the downhill force with the data of a smartphone sensor?

Apologizes for the long explanation, I couldn't find a shorter one. I'm working on a project and want to calculate the downhill force only with data I can get with the sensors of a smartphone. I ...