Questions tagged [sensor]

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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
36 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
74 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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15 views

how to calculate concentration of a produced vapour from bubbler system?

We are working on metal oxide gas/vapour sensor. To pruduce ammonia vapour we are using bubbler system. we know the volume of the liquid, and flow rate of carrier gas. How to calculate/ measure the ...
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17 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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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
25 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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13 views

Methods for detecting when a semi-permeable enclosure is opened?

I'm looking for a way to detect the approximate volume of a semi-permiable enclosure such as a cardboard box or paper envelope - the objective is to determine when the enclosure is opened. Some of the ...
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1answer
49 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
52 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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42 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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50 views

How to reduce measuring angle of JSN SR04T?

I wanted an waterproof ultrasonic sensor. So I used JSN-SR04T (NB: link to PDF document), imaged below. But the problem is it has huge measuring angle, 75%, which results in measuring obstacles which ...
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1answer
24 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
60 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
755 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
2k 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
66 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
34 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 ...
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1answer
230 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 ...
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2answers
317 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
569 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
146 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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220 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 ...
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1answer
220 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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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
162 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
253 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 ...
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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 ...
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1answer
133 views
+50

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 ...
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159 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 ...
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2answers
475 views

What's an accelerometer exactly measuring?

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 ...
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2answers
67 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 ...
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1answer
355 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 ...
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2answers
322 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 ...
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1answer
52 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 ...
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697 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 ...
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2answers
73 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-...
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0answers
271 views

Building DIY Spectrometer Foreoptics: Slit to Circular FOV

I'm currently in the process of building a spectrometer, loosely following some of the instructions from the OpenLab DIY Spectrometer project, in order to further my understanding of sensor operation. ...
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22 views

Is spectroscopic analysis of flowing air sensitive to the amount of matter or the flux?

I would like to like to go deeper in understanding the analytical and physical behaviour of air quality analysers. AQ analysers are merely based on spectroscopy (absorbance, fluorescence, ...
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3answers
73 views

A logic question on binary variables

I recently purchased some nightlights with sensors. The sensor will make sure the nightlight will only be tuned on in a dark environment. Let's assume the sensor is binary, ON or OFF. Here is the ...
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1answer
703 views

Orientation from acceleration?

I have an object that has a sensor attached on it. This sensor calculates the acceleration in all axis and angular acceleration in all axis(Keep the gravity force in mind). How can I get the Pitch, ...
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1answer
37 views

looking for a technique for conducting experiment [closed]

I have used a servomotor and a controlling circuit to produce oscillatory motion for an experiment that involves flapping of a tiny metal plate (~few mm) inside liquid. I could not be very successful ...
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1answer
1k views

Why should you be careful when you use a Hall effect probe to measure magnetic field?

Question: Why must you be careful with orientation when you use the hall effect probe to measure magnetic field? Background: In a recent Physics 2 lab, we used a magnetic field sensor which ...
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26 views

What are the possible ways of detecting cell phones in some small space? [closed]

I guess i can somehow use the fact that cell phone is a source of electromagnetic waves. Considering the space of about 8m3 volume. What equipment setup can be used in order to count phones in a given ...
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1answer
271 views

How to sensor Jerk=$d^3{\bf r}/dt^3$, or higher derivatives (4th, 5th, 6th order) when applied in the equation of motion of a ballistic missile?

Given a 6th order differential equation of motion as usually used in ballastic missile dynamic models. What kind of sensors are usually used to measure Jerk, (or higher order derivatives in kinematics)...
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1answer
111 views

Bayer filter mosaic [closed]

Hello, How a yellow or any other color that is not rgb light, get throw the Bayer filter since only allows the RGB value to pass ?
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1answer
33 views

3D thermography setup

I want to know if its possible (yet) to sense the temperature throughout a given cylinder using non-invasive techniques? Such as ultrasonic or visual imaging etc. The temperature ranges from 250-450C. ...
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1answer
78 views

Speed Calculater [closed]

I want to make an android calculator which can calculate speed of a vehicle by using mobile sensors(accelerometer or GPS) i am interested to calculate it by using accelerometer instead of GPS is it ...
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13 views

Blocking Window Distance Estimation in sCMOS Sensor setup

I am trying to establish an appropriate distance between a spectrograph output window and a CMOS sensor. The spectrograph creates a focussed image on the CMOS sensor, but I need to block out some of ...
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1answer
475 views

Sitting to Standing Posture Transition Accelerometer Triaxial Data Explanation

I don't have a physics background. (I'm a Computer Science student) I have a waist-worn accelerometer provided by the school which is quite reliable. I've captured data of sitting still to standing ...