Questions tagged [sensor]
The sensor tag has no usage guidance.
86
questions
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38 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 (...
1
vote
1answer
31 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 ...
1
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0answers
29 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 ...
1
vote
0answers
109 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
13 views
Sensitivity required for underwater gravimetric detection
What is the order of magnitude of the sensitivity required for gravimetric detection of underwater moving objects with about neutral buoyancy, perhaps not homogeneous? I reason this includes ...
2
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0answers
26 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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25 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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0answers
11 views
Calculating from sensor data
I have this kind of problem:
The vibration of a milling machine's spindle is measured with an acceleration measurement system consisting of amplifier gain, filter, A/D converter and measurement ...
0
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1answer
31 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 ...
0
votes
1answer
34 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 ...
0
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0answers
30 views
Converting IMU measurements to that of a “virtual” IMU aligned with another frame on the same rigid body
Suppose that on a rigid body/object, we mount an IMU (inertial measurement unit) that measures the angular rate $\omega \in \mathbb{R}^3$ and the acceleration $a \in \mathbb{R}^3$ from the gyroscope ...
1
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1answer
56 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 ...
0
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2answers
65 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 ...
0
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1answer
56 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 ...
0
votes
1answer
31 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 ...
0
votes
1answer
39 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 ...
0
votes
2answers
119 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 ...
2
votes
1answer
51 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 ...
0
votes
1answer
81 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
22 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 ...
1
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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 ...
0
votes
1answer
27 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 ...
2
votes
1answer
60 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 ...
0
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1answer
70 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 ...
0
votes
0answers
74 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 ...
0
votes
1answer
43 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 ...
2
votes
3answers
108 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 ...
0
votes
2answers
1k 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 ...
2
votes
2answers
5k 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 ...
4
votes
2answers
67 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 ...
0
votes
1answer
51 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
votes
1answer
279 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
votes
2answers
474 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 ...
1
vote
1answer
708 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 ...
1
vote
1answer
209 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 ...
1
vote
1answer
268 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
vote
1answer
285 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 ...
0
votes
1answer
243 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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vote
0answers
284 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 ...
2
votes
1answer
2k views
What's the difference between proper acceleration and coordinate acceleration?
I'm not a physics student, but I need to understand these concepts in order to explain what exactly an accelerometer measures and not measures, and why. Please, do not explain to me what an ...
5
votes
1answer
180 views
Cosmic Ray Detection | Florescent Light Bulbs
Main: Can cosmic rays be detected through florescent bulbs?
Can you push an AC current through a florescent lightbulb tube and measure the current draw and voltage spikes to detect cosmic rays? Is ...
2
votes
0answers
221 views
Sensitivity of human eye v.s. photodiode or photomultiplier?
I am working with optical detectors and I would like to explain to friends how small 1 pW of optical power emitted at $\lambda$ = 550 nm is related to the sensibility of the human eye.
My idea is ...
1
vote
2answers
560 views
Ficticious forces influences what an accelerometer exactly measures?
Take two different reference frames. The first one - say $\lbrace{W}\rbrace$ - is inertial and it's fixed to the Earth surface. The second one $\lbrace{B}\rbrace$ is moving and in general is rotating ...
0
votes
2answers
72 views
light point and photosensor
When a laser pointer is pointed at a screen or at a target that spot can be detected because the laser beam falls on the target and bounces back and then is detected by a photosensor.
But, what if it ...
1
vote
2answers
483 views
Does Bayer demosaicing from RGB-filter sensors work *because* the color filters are imprecise?
I have an ongoing friendly dispute with another member over on Photo Stack Exchange about the fundamentals of how RAW works, and I'm hoping you can settle it.
My understanding is that Bayer ...
1
vote
2answers
336 views
How does smartphone VR really work?
I know it doesn't sound like a physics question. But I couldn't find any satisfying answer on tech related forums, so I think that a pinch of scientific rigor is needed.
I've recently tried Google's ...
0
votes
1answer
53 views
Quadrature Modulation
I recently bought two Doppler Effect sensors HB100, but after reading more about the subject, I found out that these sensors can't distinguish if a target is moving towards or away from them.
I ...
2
votes
0answers
967 views
How Enthalpy sensor work - practically? [closed]
There are many links to enthalpy sensors used in industry, but have not found anything on the principle of their work. For example, thermometer mechanism could be a liquid (mercury) expanding ...
0
votes
2answers
76 views
Generate photons from radio waves
Photons can generate electricity via the photoelectric effect, but is it possible to go the other direction? Generate scintillations from radio waves?
The obvious answer would be to attach a light-...
