Questions tagged [measurements]

Measurements, instrumentation, calibration and metrology.

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Help on IR Proximity Sensor Inaccuracy

I want to measure the depth of a burning soil using IR proximity sensor. The sensor will be placed 20cm above the surface of the soil and measures it perpendicularly. Problem #1: I'm quite concerned ...
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27 views

Measuring an irregular cavity

A friend has a compartment in the center console of his car, he has asked me to help resize, reorder and add padding to the compartment. Basically the kind of things I'd need to know are the ...
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1answer
35 views

How to add a Gaussian noise signal with zero-mean in a given data set?

I have a real-time velocity measurement data set in a excel (.xlsx) file. I want to add the Gaussian noise signal with zero mean in this real-time data to create three set of pseudo measurements. ...
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2answers
71 views

How to measure a screw pump spindle?

My boss ordered a screw pump driving spindle from an alternative maker. That spindle, as expected, cannot turn with the two idle spindles inside the housing. Now he is asking for the spindle ...
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1answer
45 views

Inconsistant load cell readings - (static) fiction perhaps?

First off I'm not an engineer so please excuse the simple language I use to explain my question! I have an arrangement whereby I have a steel plate suspended from basically a bridge. The plate is free ...
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2answers
53 views

How to visualise/measure airflow in sauna?

I'd like to visualise/measure the flow of air in sauna to optimise the ventilation. Is there a way to colour the air (non-toxic!!!) so I may watch the flow? Or is there any other accessible technology ...
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38 views

How do you calibrate an inverted U-tube?

Say you make a U-shaped glass tube. If you fill it with water you are able to measure gas pressure by looking at the height difference of the meniscuses. In an inverted one, by turning it upside down ...
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29 views

Why would a magnetic sight glass indicate a wrong water level in a surge tank?

In a pumping station that i work, there is a magnetic sight glass attached to a surge tank which I guess there is something wrong about it because when I isolate the tube, drain it and reopen the air ...
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1answer
83 views

Measuring axial force in trapezoidal screw jack

Does anyone know of a good solution for measuring axial force in trapezoidal screw jack, like this: https://en.zimm.com/product-catalogue/screw-jack-ze-series/ze-r-trapezoidal-screw/ ? Force magnitude ...
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65 views

In Solidworks Hole Toolbox, what is Thread Minor Diameter according to DIN 13-1

Dear StackExchange Community, I recently discovered how to use the Toolbox customization to specify new threads in Solidworks 2021 SP2.0, such as ISO fine metric threads (DIN 13-3- ... -9). However, ...
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1answer
2k views

What unit of weight is that?

Recently I was weighting stuff with my dad and as I was playing with one of the old 2 kg weights I felt with my fingers number "5". After cleaning and upon further inspection it turned out ...
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1answer
20 views

Internal Diameter or External diameter measurement? [closed]

I would like to know if there is a definite way to understand what kind of diameter is indicated on the dwg by just looking at a dwg. I work in a job profile where I need to add inspection points to ...
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1answer
77 views

Tolerances in a pin-hole assembly

Hi guys, can someone explain how to do this question? This question is under Geometric Dimensioning and Tolerances and I am clueless on how to tackle problem like this. EDIT This is the explanation ...
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1answer
29 views

Safely Measuring Voltage from Solar Panels in an Experimental Research Field

I'm installing solar panels (not connected to the grid) in units out in a field for research we're doing that looks like this (this is an outdated image, but I can't find the updated one unfortunately)...
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25 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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0answers
61 views

How to measure time taken to run SCPI commands? [closed]

We all know that every program takes time to run. Normally in Python, the time built-in Python library would be sufficient to measure time-taken to run code. How may I determine how long a SCPI (...
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246 views

How to use Spectroid app to measure low frequency vibrations?

I need to measure how low frequency (vibration) changes when going through different materials. The only possible way I found is by using Spectroid app. However, I have no idea of what settings to set ...
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2answers
172 views

Error propagation in reciprocal of a measurement

I have a measure of a quantity, x, and I know the standard deviation of the measure, STDx. I want to compute the inverse of x, which is y= 1/x, but then what would happen to the standard deviation? ...
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24 views

Is there an instrument that can measure thickness of an object through strain?

So basically, I am doing a project to design a measurement tool for measuring the different layers of the quartz crucible used in the semiconductor industry. Since the crucibles undergo some ...
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2answers
34 views

Describe the magnitude of a force using real-life comparisons instead of numbers

I already asked this on physics.se, I got a suggestion to ask here, but the question became too old to migrate before I decided to do it. I did also receive an answer, and I am grateful for it but ...
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3answers
51 views

How to measure water output over time - any better solutions than tipping bucket gauge?

I'm trying to figure out how to get an automated measurement of a trickle of water over time. (Application is measuring the water output by a dehumidifier; overall output would be a few pints of water ...
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2answers
72 views

How are perfectly square blocks made from scratch?

So I'm looking into how stuff is made from scratch, starting with a surface plate which has been lapped flat using the three plate method. But almost everything I read on the subject on "the ...
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1answer
51 views

Are there any 'clever' mathematical techniques for testing a micrometer?

I've just inherited a vintage British 25 mm micrometer, and it's precious to me. You can test a spirit level by reversing it, and similarly you can for an engineer's square. We can test a right angle ...
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27 views

Vibration measurement of rotating blade

In a vibration measurement of a rotating blade, I have the following information. The vibration signal is measured using an ICP accelerometer which has the following specification Measurement range: ...
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1answer
21 views

Can you suggest a 0 to 10 Volts mesuring unit with an easy .NET (C#) API? [closed]

I am looking for a voltage input module that measures a voltage input in the range of 0 to 10 Volts (slowly changing during a 5 seconds period). It should be connected to a local Windows computer that ...
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1answer
31 views

Component for measuring push force

I would like to measure the force with which the bolt (dark blue) pushes on the break pad (grey) to stop the wheel (light blue). I am thinking that I could put some component between the bolt and the ...
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1answer
73 views

Fender Telecaster outer body measurements

I appreciate this may not be the best forum to pose this question but... I've been attempting to model a copy of a Fender Telecaster electric guitar in SketchUp. I've been mainly working from a PDF ...
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27 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 ...
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1answer
82 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. ...
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3answers
257 views

Mechanism for controlling the clamping force

I am working on upgrading a research project on wind energy. They are trying to measure the performance of wind blade designs in a small wind tunnel (i.e. their models are relatively small). What they ...
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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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7answers
4k views

How can I measure correctly with a ruler?

When measuring with a ruler divided into mm lines, should I include the lines by themselves or only in between them? I illustrated the problem. (I took an example of measuring of 10 mm with two long ...
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2answers
47 views

Why are 0-10V signals de-facto standard in HVAC applications, when 4-20mA is more common in other applications?

I've been involved in a few projects with HVAC systems, where sensors etc. generally used 0-10 V signals, and looking at catalogues of Buderus and other suppliers this still appears to be the standard....
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1answer
74 views

How do engineers work with extremely small objects?

Please excuse me if my question is not well-worded. My background is pure mathematics and I am not familiar with engineering, but sometimes I feel fascinated by the things engineers have achieved. ...
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2answers
62 views

Accurate method or instrument to measure density of shaving cream foam or whipped cream foam?

I am currently filling a "standard" stainless steel cup of known volume with foam and then I weigh it. Then I calculate density. This method is pretty messy and I have to be careful about how I fill ...
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22 views

Estimating trunk rotation using frontal and sagittal views

I am doing an experiment regarding elbow flexion's effect on peak sprinting velocity and we want to measure trunk rotation and shoulder rotation during our trials. We don't have an overhead camera so ...
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2answers
72 views

Measuring a pattern size on a flat surface

I want to manually measure the dimension of a pattern printed on a flat surface, with an accuracy of about 0.1mm. For simplicity sake, let's say this is a black rectangle, printed on a white ...
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30 views

How to measure and create PVT diagram

We have all seen PVT diagrams. From my understanding one should measure pressure, volume and temperature on or near the outside of the system. Volume: maybe by displacing water initially and then ...
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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
163 views

How to measure the power output of a stirling engine

I'm doing a project for thermodynamics where I have to measure the power (work over time) of a Stirling engine for varying temperature differences. I don't necessarily need an exact answer (as in: ... ...
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1answer
41 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 ...
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1answer
165 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 ...
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33 views

What is dead beat reading?

I was reading about characteristic of a comparator. It states Comparator indicator device should be such that the readings are obtained in least possible time and for this magnification system should ...
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1answer
42 views

Expression of uncertainty measurement

I have a problem with the expression of a measurement result. I have a resistance decade box used as variable resistor in order to balance a Wheatstone Bridge. Let's call this resistance decade box $...
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1answer
18 views

Measuring EM radiation power over surface area

I didn't make it obvious enough below that I was interested mostly in infrared, as the current use case is measuring power radiated from warm objects and from the ground. As pointed out in comment by @...
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1answer
78 views

BJT Output Characteristics Question

Ok, so I am pretty confused at the moment with a question that I have been given to work out by my lecturer and was wondering if I could get some guidance with it. I will attach images of the question ...
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0answers
16 views

how do you calculate viscocity from torque arm load cell measurements?

I have a piece of company developed equipment that uses a pot mounted on a rotating base plate with a 0.15m torque arm and load cell, a mixing paddle is used to stir the mixture while the controller ...
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0answers
53 views

How can I calculate the smallest voltage a given adc can read?

I have a project where I'd need to measure small voltage (0.05 mV) output of a wheatstone bridge with an arduino mini pro. Based on my previous question most probably it can't be done with its ...
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1answer
43 views

what is the range of the measurable relative elasticity with a commonly used strain gauge

I'm looking for a data that what is the typical application range for a common uni directional strain gauge like used in weight scales? I've read about around 200 ppm in a research gate article, can ...
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1answer
67 views

what does 0.1% FS +/- 0.02 mean?

Let's assume a DMM is specified to have accuracy "0.1% FS +/-0.02" when used on the 50 V range. I get that 0.1% FS means the true value will lie somewhere between measured value - 0.05 and measured ...

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