Questions tagged [sensors]
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181
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23 views
Finding force distribution using accelerometer data
The team I'm currently working for is trying to compare bushings with different durometer ratings in the front suspension using single axis(z) accelerometer data during curb impacts. The current ...
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25 views
Detecting goals blocked on a foosball table
I am trying to find a way to detect when a goal is blocked on a foosball/kicker table. I have a HD camera above the table and a laser sensor built into each goal. The lasers can detect when a goal is ...
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36 views
What is the feedback signal used in the speed control of a brushless DC motor?
In a brush-less DC (BLDC) motor the commonly used speed is sensed using the feedback from Hall effect sensors and the back or counter EMF. The linked article on Wikipedia also mentions that 'Other ...
2
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2answers
56 views
Measuring distance to a non perpendicular surface
I am a Mechanical engineering student and i am completely new to arduino and need some advice. i have a project to measure the maximum deflection in a sailplane wing (up to 9 meters)
How do i measure ...
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29 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 ...
0
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2answers
27 views
Are cameras' CCDs just elaborate tiny solar cells?
While watching How It's Made episode on CCDs, this just springed to my mind... I always though of CCDs as of some kind of alien technology. Only now I realized that it's just an array of silica ...
2
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2answers
62 views
How can one make the beam angle smaller on an ultrasonic sensor?
I'm trying to create higher resolution data with a beam angle of 5> degrees (as close as 1 degree as possible). I have been experimenting with creating using an aluminum casing around the sensor ...
0
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1answer
21 views
Passive Infrared Sensors (PIR) spectrum and reflections
I have a common PIR occupancy sensor (Lutron MS-OPS5M-WH). I am trying to get the sensor to cover an irregular-shaped room.
I could expand the field-of-view of the sensor to cover the whole room by ...
1
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1answer
20 views
Sensor compatibility with power source
I have a sensor whose datasheet mentions that it should be connected to 5V Vcc.
A green LED glows on the sensor when it is powered from the source at 5V.
However, even if I power it with 3.3V, still ...
0
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1answer
26 views
Complementary filter in MPU_6050 is giving me the wrong answer when the system is accelerating
So I am using a complementary filter to find the attitude in my quadcopter, doing the following
$$\text{angle} = 0.98\cdot (\text{angle}+\text{dt}\cdot \text{angle_rate})+0.02\cdot \text{...
1
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2answers
67 views
How is the YAW angle calculated by an IMU sensor?
Say a body rotates by 90 degrees, then the yaw angle will be 90 which can be calculated using the data provided by IMU.
Now from that point, the body traverses some distance and is again rotated by 90 ...
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1answer
28 views
Do LiDAR sensors generate point cloud data from a single collection or build them up over multiple collections?
I am currently writing a background section on lidar sensing for part of my dissertation. I have either confused myself or not thought on the topic enough and I am attempting to gain a clearer ...
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30 views
Laser Tape Measures and Range Finders
Is there a technology in Laser Tape Measures which differs from the ones in Laser Range Finders (ToF or Triangulation)?
It seems that Laser Tape Measures are less expensive than any Laser Range Finder ...
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0answers
20 views
How to sanitarily measure vacuum in milk?
I would like to measure the vacuum inside of a tube which will contain air and milk. A vacuum pump attached to the tube will maintain a vacuum of around 15 inHg.
Are there inexpensive sensors I can ...
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0answers
26 views
How does the number of cycles for averaging in a lock-in amplifier relate to low-pass filtering and where do I set it?
Please forgive me if I ask too many questions at once or I am too much of a rookie. I want to understand the working-principle of lock-in amplifiers (LIAs).
I understood the calculation that yields ...
1
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1answer
54 views
Ceramic pressure measurement - piezoelectrical or capacitive?
Context: I'm writing about an old industrial training facility used for a petrochemical process.
In this training facility, there is a 3-phase separator. On that separator is a pressure measurement. ...
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0answers
18 views
Is it possible to set up an ultrasonic range-finding system using a separate transmitter and receiver across 30m distance?
I need to set up a system capable of detecting the distance between an object moving further away and an anchor point. This object would be traveling through a slightly curved tunnel (of 1m diameter), ...
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1answer
59 views
Can I use loadcell for vibrating force measurement?
Is it possible to use a load cell to measure a force that is vibrating? The idea is to measure that force that is getting into the load cell in a sweep of frequencies and vibration is NOT a noise. ...
0
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1answer
32 views
Orientation of wire in linear position wire sensors
Talking about a wire potentiometer, I was wondering about the way it could be used after installation. as you know, wire sensors have a roll of wire inside them that come out of a hole, and it sounds ...
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1answer
26 views
Schematic of a resettable thermostat
You can put 2 or 4 or even 6 pcs of this in series to make sure at least one will work or open if it reaches say 55 degree celsius, right? And there is no resistances to consider when its close and in ...
2
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0answers
22 views
allan-variance noise terms of MEMS accelerometer
Specific noise terms are given in datasheets of MEMS sensors.
In example the specification of accelerometer contains information about random walk and in some cases the bias instability.
Both ...
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0answers
29 views
Low accuracy current feedback measurement in motor control
Given a very low accuracy current sensor in a 3 phase inverter (in my case used for motor control) what is the best way to tackle the issue and keep reasonable performance and robustness at the same ...
4
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1answer
47 views
Is there an industry consensus standard for storing sensor data?
I would like to know what standard(s) may exist for formatting log data from sensors that record information such as:
temperature
pressure
humidity
vibration
acceleration vector
magnetic field vector
...
2
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0answers
99 views
What is meant by “accuracy within factor of 2” in sensors?
I've spent quite some time googling the meaning of "factor of (number)" in sensor accuracy but could not find any document explaining the meaning of this expression used to describe sensor accuracy. ...
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2answers
48 views
How do fiber optic sensors detect strains in a structure?
I am working on a project on detecting damage in structures using fiber optic sensors. I read the paper Structural Health Monitoring in Composite Structures by Fiber-Optic Sensors and found out that ...
0
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0answers
64 views
Making a machine to sort out old bolts, washers, nuts etc in workshop
I spend a lot of time in my workshop sorting out and putting back into their boxes bunches of screws, washers, nuts and other assorted niknaks and I want to make a machine to take this chore off my ...
3
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2answers
42 views
H2 Sensor in N2 environment
We develop a test station where we might have H2 leakage.
To prevent explosion we are considering intertisation using N2 gas (primary explosion protection).
However we also want to detect leakage ...
0
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1answer
44 views
Need help with reverse engineering a sensor
I have a pressure/temperature sensor for a vehicle, which I decided to tear apart to see exactly how the sensor works.
This sensor as designed by the manufacturer it is meant to be immersed in oil to ...
1
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1answer
33 views
Design of a hydrogen and corrosion sensor query
I’m designing a hydrogen and corrosion sensor. A thin film changes resistance based on hydrogen concentration. Then the capacitance between two electrodes will change depending on substrate thickness (...
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0answers
25 views
How to design a method to estimate vx=speed in direction of swimming
We have a body that goes underwater (let's say a whale) with magnetometer and accelerometer data. I also have GPS, date, depth, pressure and temperature data.
I want to know if there is any simple way ...
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1answer
40 views
What are the simplest available methods for monitoring pressure and airflow in a 22mm diameter pipe?
In the emergency case that more than one person must share a mechanical ventilator, the medical professionals lose per-patient monitoring of pressure and airflow.
To that end, what are the simplest ...
1
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1answer
78 views
How to reduce oscillations (rapid changes of control signal) when controlling a real system, which occur due to noise in measurement from sensors?
I have a real mechanical system (ball & beam) which I want to control. The system is approximated by the second order transfer function:
$$ T(s) = \frac{b_0}{s^2+a_1s+a_2} $$
and in state-space ...
2
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5answers
121 views
What sensors/methods can be used from the roadside to determine if a truck is loaded or empty - without weighing it?
What sensor, using what physical principle, can penetrate a closed rectangular object like the trailer of a truck and tell if the space is empty or loaded?
Why is this question relevant? One of the ...
2
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0answers
36 views
What is the gel used for covering the strain gauge in the load cell?
We have one imported strain gauge load cell, which shown open circuit in the input impedance. I removed the protective gel and corrected the wiring. Now the load cell is working. But I want to cover ...
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0answers
23 views
Moisture sensor for Mixers
I'm looking for alternatives to measure the moisture content in a concrete mixer machine. The ones on the market are expensive, like Hidro-Mix for apparent reasons; mixers are a hostile environment ...
2
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1answer
70 views
Kalman filter for sensor fusion — what is the advantage?
Is there any meaning of using Kalman Filter for cases when you do not have good statistical model of the system?
For example, if you have a drone and it has IMU sensor and GPS sensor. You do not have ...
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0answers
17 views
Accurate distance sensor via soft materials
I'm trying to find a sensor that can measure distance between sensor and some sort of detectable material (metal or small wireless chip) size of no more than a penny.
It should be able to measure ...
0
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0answers
18 views
What object characteristics may cause significant distance measurement deviations in Sharp optical sensors?
Not sure if this is the right place to ask this question, but anyways. I'm not very fond of circuits and stuff, but I've got a test question I really need to answer. The question is in the title, ...
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12 views
Will expanding metal disrupt my motion sensor?
I am trying to install a door motion sensor in a environment that will get very hot for our work. So the door could heat up to temperature of 150-200°F. We built the frames and door to handle the ...
2
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1answer
51 views
Can a sensor tell the difference between gravity vs. acceleration?
Are the effects of gravity and acceleration identical to the point that no sensor can tell the difference?
2
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0answers
59 views
How to compare two acceleration sensors side-by-side?
I have a single axis analog capacitive acceleration sensor (from PCB Piezotronics) which is very reliable but expensive. Now I need more axis, unfortunately can not afford buying anymore. So I have ...
0
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1answer
37 views
Typical IMU accelerations and angular velocities for lower limbs
Is there a dataset out there right now that shows the typical acceleration and angular velocity values for sensors attached to the thigh, shank, and feet for standard walking?
Or literature/textbook ...
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0answers
26 views
How to choose order and cut-off frequency for low-pass Butterworth filter?
When using IMU data (accelerations and angular velocities), many papers use a 4th order low-pass butterworth filter with a cutoff frequency of 5 Hz. However, none of them really justify why those ...
0
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1answer
76 views
Why are FBG sensors recalibrated every 10 years?
So, I am working with FBG sensors and I have read that those sensors need to be re-calibrated every 10 years to get accurate measurements. But no where on the internet (AFAIK) is it explained why ...
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0answers
24 views
How do cordless lawn mowers determine lawn density?
Some cordless lawn mowers have a feature that causes the motor to cut off when the mower is rolled over a driveway or over a section of lawn where the grass is very sparse. How does the mower sense ...
3
votes
2answers
5k views
What is the difference between washer and O-ring? what is their advantages over the other?
I am designing a hydrophone, from the piezo buzzer. To hold the circular piezo plate, I have designed a mechanical fixture. I need to use washer/o-ring to make it leak-proof. I am confused about which ...
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1answer
39 views
How can I confirm nL Volume Measurement for Pump and Sensor Calibration
I'm dispensing around 1uL of volume with 1% accuracy. Although I'm confident in my pump, I'd like to be able to routinely confirm that I'm getting the exact volume I'm requesting every time.
How can ...
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0answers
17 views
motion gesture and axis definition
I read something about defining hand gesture, which include mid-air hand gesture (e.g a peace sign with the two fingers moving one after another), touch-based gesture (e.g. on touch screen), and ...
3
votes
1answer
38 views
What's the most practical way to measure angular velocity for small rotations?
I'm looking to measure the angular velocity of an arm as it moves. It seems to be a difficult thing to research, since the term 'angular velocity/frequency' is usually reserved for other areas of ...
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0answers
46 views
How much does loading a load cell in other directions than the direction it was designed for effect the readings?
I am looking into using this TAL230B miniature type load cell to measure forces in x and y direction. The normal sensor loading is displayed in image 1. What is the effect of loading them as in image ...
